bmj open€¦ · for peer review only 1 prevalence and patterns of congenital heart diseases in...

For peer review only

Prevalence and patterns of congenital heart diseases in Africa: a systematic review and meta-analysis protocol

Journal: BMJ Open

Manuscript ID bmjopen-2016-015633

Article Type: Protocol

Date Submitted by the Author: 19-Dec-2016

Complete List of Authors: Tankeu, Aurel; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Bigna, Jean Joel; Centre Pasteur of Cameroon, Epidemiology and Public Health Nansseu, Jobert Richie; Mother and Child Centre, Chantal Biya Foundation, Sickle cell unit Aminde, Leopold; Clinical Research Education, Networking & Consultancy (CRENC), Douala and Nguti District Hospital,

Danwang, Celestin; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Mazou, Temgoua Ngou ; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Noubiap, Jean Jacques; Edea Regional Hospital, Internal Medicine Unit

<b>Primary Subject Heading</b>:

Cardiovascular medicine

Secondary Subject Heading: Epidemiology

Keywords: Congenital heart disease < CARDIOLOGY, Africa, Heart defects, cardiac malformation

For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml

BMJ Open on A

pril 20, 2020 by guest. Protected by copyright.

http://bmjopen.bm

j.com/

BM

J Open: first published as 10.1136/bm

jopen-2016-015633 on 14 February 2017. D

ownloaded from

http://bmjopen.bmj.com/


1

Prevalence and patterns of congenital heart diseases in Africa: a systematic

review and meta-analysis protocol

Aurel T. Tankeu1, Jean Joel R. Bigna

2,3, Jobert Richie N. Nansseu

4,5, Leopold Ndemnge

Aminde6, Celestin Danwang

7, Temgoua Ngou Mazou

1, Jean Jacques N. Noubiap

8*

1. Department of Internal Medicine and Specialties, Faculty of Medicine and Biomedical

Sciences, Yaoundé, Cameroon

2. Department of Epidemiology and Public Health, Centre Pasteur of Cameroon, Yaoundé,

Cameroon

3. Faculty of Medicine, University of Paris Sud XI, Le Kremlin Bicêtre, France

4. Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of

Yaoundé 1, Yaoundé, Cameroon

5. Sickle Cell Disease Unit, Mother and Child Centre of the Chantal Biya Foundation,

Yaoundé, Cameroon

6. Faculty of Medicine & Biomedical Sciences, School of Public Health, The University of

Queensland, Brisbane, Queensland, Australia

7. Department of Surgery and Specialties, Faculty of Medicine and Biomedical Sciences,

University of Yaoundé 1, Yaoundé, Cameroon

8. Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape

Town, South Africa

E-mail addresses: ATT: [email protected]; JJRB: [email protected]; JRNN:

[email protected]; LNA: [email protected]; CD: [email protected];

TNM: [email protected]; JJNN: [email protected]

*Corresponding author: Dr. Jean Jacques N. Noubiap. Department of Medicine, Groote

Schuur Hospital and University of Cape Town, 7295, Cape Town, South Africa.

[email protected]

Page 1 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960

on April 20, 2020 by guest. P

rotected by copyright.http://bm

jopen.bmj.com

/B

MJ O

pen: first published as 10.1136/bmjopen-2016-015633 on 14 F

ebruary 2017. Dow

nloaded from



2

Abstract

Introduction

Congenital heart diseases (CHD) are common causes of cardiovascular morbidity and

mortality among young children and adolescents living in Africa. Accurate epidemiological

data are needed in order to evaluate and improve preventive strategies. This review aims to

determine the prevalence of CHD and their main patterns in Africa.

Methods and analysis

This systematic review and meta-analysis will include cross-sectional, case–control and

cohort studies of populations residing inside African countries, which have reported the

prevalence of CHD; confirmed by an echocardiographic examination, and/or describing

different patterns of these abnormalities in Africa. Relevant abstracts published without

language restriction from January 1st, 1986 to December 31

st 2016 will be searched in

PubMed, Exerpta Medica Database and online African journals as well as references of

included articles and relevant reviews. Two review authors will independently screen, select

studies, extract data and assess the risk of bias in each study. The study-specific estimates will

be pooled through a random-effects meta-analysis model to obtain an overall summary

estimate of the prevalence of CHD across studies. Clinical and statistical heterogeneity will be

assessed, and we will pool studies judged to be clinically homogenous. On the other hand,

statistical heterogeneity will be evaluated by the χ2 test on Cochrane’s Q statistic. Funnel-

plots analysis and Egger’s test will be used to detect publication bias. Results will be

presented by geographic region (central, eastern, northern, southern and western Africa).

Ethics and dissemination

Page 2 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



3

The current study will be based on published data, and thus ethical approval is not required.

This systematic review and meta-analysis is expected to serve as a base which could help

estimating and evaluating the burden of these abnormalities on the African continent. The

final report of this study will be published in a peer-reviewed journal.

Review registration number

PROSPERO CRD42016052880.

Funding

None.

Page 3 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



4

Strengths and limitations of the study

• To the best of our knowledge, this will be the first systematic review on the topic of

Congenital heart diseases (CHD) to summarize available data on African continent.

• We will use powerful meta-analysis techniques to derive accurate estimates.

• A major possible limitation of this study could be the limited data with predominance of

hospital-based studies. Indeed, these studies may not reflect the true prevalence of CHD in

the general population, therefore overestimating these threats.

• Another possible limitation may be heterogeneity of studies done on the topic in Africa.

Page 4 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



5

Introduction

Congenital heart disease or congenital heart defect (CHD) is a problem of heart’s structure

and function present at birth, affecting heart or adjacent great blood vessels present either at

the time of birth or detected later in life.1

2 Worldwide, CHD are the main heart diseases

found in children and constitute one of the major causes of infant mortality, particularly in

developing countries.2 3

They also represent the most common of all congenital malformations

accounting for more than 20% of perinatal deaths.4 5

Their estimate prevalence is eight cases

per 1,000 live births across the globe, representing approximately 1.35 million newborns each

year with CHD but these figures vary worldwide.2 For instance, the incidence of CHD in

different studies varies from about 4/1.000 to 50/1.000 live births and despite advances in

detection and treatment, congenital heart diseases accounts for 3% of all infant deaths and

46% of death from congenital malformations in developed countries such as USA.4-6

In

addition, these abnormalities can be life threatening in early childhood, and children born with

severe forms are at approximately 12 times higher risk of mortality in the first year of life.7

Thus, hundreds of thousands of children die each year from CHD, while millions more remain

in desperate need of treatment in the developing world.8 Since mortality and morbidity from

cardiac disease among children in developing countries are gaining recognition, there is a

need of summarized data on CHD in African continent. Africa is thought to have one of the

highest prevalence of heart diseases in children and young adults, including CHD but main

findings include evidence that the CHD burden is underestimated mainly due to the poor

outcome of African children with CHD.7 From a global point of view, the epidemiology of

these abnormalities is still unknown in Africa with few or even no global data on the topic.

Reducing the prevalence of these diseases is urgent and requires a real inventory of the

premises of the problem that would clarify the issue for more effective prevention strategies

Page 5 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



6

and improved management. In this context, we present the protocol for a systematic review

and meta-analysis to assess the prevalence and patterns of CHD in Africa.

Objective

This systematic review and meta-analysis aims to determine the prevalence and of CHD and

their different patterns in Africa.

Review question

This review of studies published in the past 30 years, from 1st January 1986 to 31

st December

2016, should answer the following questions

1. What is the prevalence of CHD among African populations?

2. What are the different patterns of CHD in Africa?


Criteria for considering studies for the review

Inclusion criteria

We will include:

1. Cross-sectional, case–control or cohort studies of populations residing in African countries

reporting the prevalence of CHD in African countries or enough data to compute these

estimates.

Page 6 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



7

2. Studies describing the different patterns of CHD on the African continent.

Exclusion criteria

We will not consider:

1. Studies on congenital abnormalities involving the heart but not considered as CHD (Long

QT syndrome, congenital but functionless abnormalities of the heart, cardiomyopathies).

2. Studies conducted among populations of African origin residing outside Africa.

3. Studies in subgroups of participants selected on the basis of cardiac murmurs without

echocardiographic confirmation of CHD (e.g. suspected but non-confirmed CHD).

4. Studies including many pathologies in which it will not be possible to extract data

regarding CHD or studies reporting congenital abnormalities affecting many systems at time.

5. Letters, reviews, commentaries and editorials.

6. Studies lacking key data and/or explicit method description.

7. Duplicates: for studies published in more than one paper, the most comprehensive one

reporting the largest sample size will be considered.

8. Studies whose full data will not be accessible even after request from the authors.

Search strategy for identifying relevant studies

The search strategy will be implemented in two stages:

Bibliographic database searches

A. Relevant abstracts published without language restriction on the prevalence, incidence,

main etiologies and clinical features of CHD in Africa will be identified via searching

Page 7 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



8

PubMed, Exerpta Medica Database, and online African journals. The search will be limited to

studies published between January 1st, 1986 and December 31

st, 2016. Both text words and

medical subject heading terms will be used. Key search terms include: ‘congenital heart

defects’ or ‘congenital heart disease’ as well as the name of every known pattern of these

abnormalities. We will also use individual country names for the 54 African countries as

additional key search terms for more abstracts on the subject. Conference proceedings of the

study period will also be identified through databases and checked. The main search strategy

is shown in Table 1.

B. The abstracts of all eligible papers will be reviewed and full articles will be accessed

through PubMed, Exerpta Medica Database, Google Scholar, HINARI or journals’ websites.

Additionally, references of all relevant articles and reviews will be scrutinized for other

potential data sources, and their full texts will be accessed in a similar way. The authors

whose full text papers will not be accessible by the numerous internet-based sources will be

directly contacted to provide them. In case of no feedback from these authors, the

corresponding studies will be excluded.

Searching for others sources

References of all relevant researches and review articles will be scrutinized for additional

potential data sources, and their full texts will be accessed in a similar way. Those authors


directly contacted via email to provide them. In case of no feedback from these authors, the


Selection of studies for inclusion in the review

Page 8 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



9

Assessment of eligible papers will be independently run by two authors using an assessment

guide to ensure that the selection criteria are reliably applied by all the team. They will screen

the titles and abstracts obtained from the searches and retrieve the full texts of potentially

eligible papers by at least one author. Thereafter, they will independently review the full text

of each potentially eligible study, compare their results and resolve any discrepancy by

discussion and consensus. If a decision is not reached, a third review author will be consulted

for arbitration.

Assessment of methodological quality and reporting of data

The Newcastle-Ottawa Scale (NOS) for assessing the quality of non-randomized studies in

meta-analyses will be used to assess the methodological quality and risk of bias for each study

(see online supplementary appendix S1).9 Risk of bias and quality scores will be presented in

a table.

Data extraction and management

A data extraction sheet will be used to collect information about the author, the country, the

year of publication, the study design, the sample size population, the mean/median age of the

population, the age range, the sex ratio, the prevalence of CHD as well as main patterns when

available. Where prevalence or information for calculating them (eg. sample size, number of

outcomes) are lacking, we will directly contact the corresponding author to request the

information. In case of multinational studies, we will separate the results to show the

prevalence and etiologies within individual countries. Where it will not be possible to

disaggregate the data by country, the study will be presented as one and the countries in which

the study was done will be shown.

Data synthesis and analysis

Page 9 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



10

Data will be analyzed using Stata software version 13 (Stata Corp V.13, Texas, USA). A

meta-analysis will be conducted for data obtained from studies in which CHD has the same

etiologies, Standard errors (SEs) for the study-specific estimates will first be determined from

the point estimate and the appropriate denominators, assuming a binominal distribution. Then,

the study-specific estimates will be pooled through a random-effects meta-analysis model to

obtain an overall summary estimate of the prevalence across studies, after stabilizing the

variance of individual studies using the Freeman-Tukey double arc-sine transformation (to

keep the effect of studies with extremely small or extremely large estimates).10

Heterogeneity

will be evaluated by the χ² test on Cochrane’s Q statistic11

which is quantified by I² values,

assuming that I² values of 25%, 50% and 75% represent low, medium and high heterogeneity

respectively.12

Where substantial heterogeneity will be detected, a subgroup analysis will be

performed to detect its possible sources using the following grouping variables: type of CHD,

consequences on cardiac hemodynamic, study setting (hospital vs community-based), age of

diagnosis, geographical area (central, eastern, northern, southern and western Africa), and

study quality. Difference between groups will be detected if p value < 0.05. Inter-rater

agreement for study inclusion will be assessed using Cohen’s κappa coefficient.13

Funnel

plots analysis and Egger’s test14

will be done to detect publication bias. Publication bias will

be confirmed if p value on Egger’s test < 0.10. Results will be presented by geographic region

(central, eastern, northern, southern and western Africa).

Presentation and reporting of results

The study selection process will be summarized using a flow diagram. Reasons for studies’

exclusion will be described. The report will follow the PRISMA (Preferred Reporting Items

for systematic review and Meta-analysis) Guidelines {Citation}. Tables and forest plots will

Page 10 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



11

serve to summarize quantitative data where appropriate. We will examine prevalence and

etiologies by region, setting (hospital or community) and time period depending on the data

available. We plan to report on quality scores and risk of bias for each eligible study. This

may be tabulated and accompanied by narrative summaries.

Conclusion

CHD represent the second major cause of CVD morbidity and mortality among young

Africans. Their management is limited in Africa in an inadequate socio-economic

environment with insufficient technical platform and human resources. Moreover, the global

burden of these conditions is unknown on the continent. Therefore, it becomes urgent to

provide summarized recent and reliable data in order to help estimating the prevalence as well

as etiologies in Africa in other to highlight the importance of these abnormalities and the need

to reinforce of effective preventives strategies based on systematic screening of cardiac

abnormalities in the perinatal period. We hope that this review will help sensitizing health

care providers on the problem represented by CHD in Africa, assist and support the

implementation of new policies, practices and researches by providing insights into the

current situation and the true impact of CHD on African continent as well as shortcomings

that can guide future research around this topic.

Protocol and registration

The protocol for this review has been published in the PROSPERO International Prospective

Register of systematic reviews (http://www.crd.york.ac.uk/PROSPERO), registration number:

PROSPERO CRD42016052880

Page 11 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



12

Authors’ Contributions

ATT and JJNN conceived and designed the protocol. ATT drafted the manuscript. JJRB,

JRNN, LNA, CD, TNM and JJNN critically revised the manuscript for methodological and

intellectual content. JJNN is the guarantor of the review. All authors approved the final

version of this manuscript.

Competing interests

None.

Funding

This research received no specific grant from any funding agency in the public, commercial or

not-for-profit sectors.

Data sharing statement

No additional data are available.

References

1. Tantchou Tchoumi JC, Butera G, Giamberti A, et al. Occurrence and pattern of

congenital heart diseases in a rural area of sub-Saharan Africa. Cardiovasc J Afr.

2011;22(2):63–6.

2. Chelo D, Nguefack F, Menanga AP, et al. Spectrum of heart diseases in children: an

echocardiographic study of 1,666 subjects in a pediatric hospital, Yaounde, Cameroon.

Cardiovasc Diagn Ther. 2016;6(1):10–9.

3. Kouame BD, N’guetta-Brou IA, Kouame GSY, et al. Epidemiology of congenital

abnormalities in West Africa: Results of a descriptive study in teaching hospitals in

Abidjan: Cote d’Ivoire. Afr J Paediatr Surg. 2015;12(1):51–5.

Page 12 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



13

4. Sadowski SL. Congenital cardiac disease in the newborn infant: past, present, and future.

Crit Care Nurs Clin North Am. 2009;21(1):37–48.

5. Hoffman JIE, Kaplan S. The incidence of congenital heart disease. J Am Coll Cardiol.

2002;39(12):1890–900.

6. Chinawa JM, Eze JC, Obi I, et al. Synopsis of congenital cardiac disease among children

attending University of Nigeria Teaching Hospital Ituku Ozalla, Enugu. BMC Res

Notes. 2013;6:475.

7. Otaigbe BE, Tabansi PN. Congenital heart disease in the Niger Delta region of Nigeria:

a four-year prospective echocardiographic analysis. Cardiovasc J Afr. 2014;25(6):265–8.

8. Massoure PL, Roche NC, Lamblin G, et al. Cardiovascular disease in children in

Djibouti: a single-centre study. Pan Afr Med J. 2013;14:141.

9. Turner L, Boutron I, Hróbjartsson A, et al. The evolution of assessing bias in Cochrane

systematic reviews of interventions: celebrating methodological contributions of the

Cochrane Collaboration. Syst Rev. 2013;2:79.

10. Miller JJ. The Inverse of the Freeman – Tukey Double Arcsine Transformation. Am

Stat. 1978;32(4):138–138.

11. Cochran GW. The Combination of Estimates from Different Experiments. Biometrics

1954;10(1):101-29.

12. Huedo-Medina TB, Sánchez-Meca J, Marín-Martínez F, Botella J. Assessing

heterogeneity in meta-analysis: Q statistic or I2 index? Psychol Methods.

2006;11(2):193–206.

13. McHugh ML. Interrater reliability: the kappa statistic. Biochem Medica. 2012

15;22(3):276–82.

14. Egger M, Davey Smith G, Schneider M, et al. Bias in meta-analysis detected by a

simple, graphical test. Bmj 1997;315(7109):629-34.

Page 13 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



14

Table 1: Search strategy for PubMed

Search Search terms

#1 congenital heart OR heart defects OR heart murmur OR fallot OR ventricular

defect OR atrial defect OR septal defect OR great vessels transposition OR

foramen ovale OR single ventricle OR persistent ductus arteriosus OR dorv

OR avsd OR ASD OR VSD OR BAV OR d-tga OR aorta coarctation OR

hypoplastic heart OR total anomalous pulmonary venous connection OR

truncus arteriosus OR ebstein s abnormality OR tricuspid atresia OR cyanotic

heart OR non cyanotic heart OR mitral stenosis[tw] OR mitral

incompetence[tw] OR tricuspid incompetence[MeSH terms] OR tricuspid

stenosis[tw] OR pulmonary stenosis[tw] OR pulmonary incompetence[tw]

OR aortic incompetence[tw] OR aortic stenosis[MeSH terms] OR heart

murmur[tw] OR Atrial septal defect[tw] OR Ventricular septal defect[tw] OR

Pulmonary atresia[tw] OR Aortic atresia[tw] OR echocardiography

abnormalities[tw] OR Fallot tetralogy[tw] OR aorta coarctation[tw] OR

cyanotic cardiac abnormalities[tw] OR atrioventricular septal defects[tw] OR

biscupid aortic valve[tw] OR double outlet right ventricle[tw] OR patent

ductus arteriosus[tw] OR single ventricle[tw] OR great arteries

transposition[tw] OR hypoplastic heart[tw] OR tricuspid atresia[tw] OR

Ebstein abnormality[tw] OR truncus arteriosus[tw] OR total anomalous

pulmonary venous connection[tw]

#2 (Africa* OR Algeria OR Angola OR Benin OR Botswana OR "Burkina Faso"

OR Burundi OR Cameroon OR "Canary Islands" OR "Cape Verde" OR

"Central African Republic" OR Chad OR Comoros OR Congo OR

Page 14 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



15

"Democratic Republic of Congo" OR Djibouti OR Egypt OR "Equatorial

Guinea" OR Eritrea OR Ethiopia OR Gabon OR Gambia OR Ghana OR

Guinea OR "Guinea Bissau" OR "Ivory Coast" OR "Cote d'Ivoire" OR

Jamahiriya OR Kenya OR Lesotho OR Liberia OR Libya OR Madagascar

OR Malawi OR Mali OR Mauritania OR Mauritius OR Mayotte OR Morocco

OR Mozambique OR Namibia OR Niger OR Nigeria OR Principe OR

Reunion OR Rwanda OR "Sao Tome" OR Senegal OR Seychelles OR "Sierra

Leone" OR Somalia OR "South Africa" OR “South Sudan” OR "St Helena"

OR Sudan OR Swaziland OR Tanzania OR Togo OR Tunisia OR Uganda OR

"Western Sahara" OR Zaire OR Zambia OR Zimbabwe OR "Central Africa"

OR "Central African" OR "West Africa" OR "West African" OR "Western

Africa" OR "Western African" OR "East Africa" OR "East African" OR

"Eastern Africa" OR "Eastern African" OR "North Africa" OR "North

African" OR "Northern Africa" OR "Northern African" OR "South African"

OR "Southern Africa" OR "Southern African" OR "sub Saharan Africa" OR

"sub Saharan African" OR "subSaharan Africa" OR "subSaharan African")

NOT ("guinea pig" OR "guinea pigs" OR "aspergillus niger")

#3 #1 AND #2

#4 # 3 Limits: : 1986/01/01 to 2016/12/31

Page 15 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



NEWCASTLE - OTTAWA QUALITY ASSESSMENT SCALE

CASE CONTROL STUDIES

Note: A study can be awarded a maximum of one star for each numbered item within the Selection and

Exposure categories. A maximum of two stars can be given for Comparability.

Selection

1) Is the case definition adequate?

a) yes, with independent validation ��

b) yes, eg record linkage or based on self reports

c) no description

2) Representativeness of the cases

a) consecutive or obviously representative series of cases ��

b) potential for selection biases or not stated

3) Selection of Controls

a) community controls ��

b) hospital controls

c) no description

4) Definition of Controls

a) no history of disease (endpoint) ��

b) no description of source

Comparability

1) Comparability of cases and controls on the basis of the design or analysis

a) study controls for _______________ (Select the most important factor.) ��

b) study controls for any additional factor �� (This criteria could be modified to indicate specific

control for a second important factor.)

Exposure

1) Ascertainment of exposure

a) secure record (eg surgical records) ��

b) structured interview where blind to case/control status ��

c) interview not blinded to case/control status

d) written self report or medical record only

e) no description

2) Same method of ascertainment for cases and controls

a) yes ��

b) no

3) Non-Response rate

a) same rate for both groups ��

b) non respondents described

c) rate different and no designation

Page 16 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from




COHORT STUDIES


Outcome categories. A maximum of two stars can be given for Comparability

Selection

1) Representativeness of the exposed cohort

a) truly representative of the average _______________ (describe) in the community ��

b) somewhat representative of the average ______________ in the community ��

c) selected group of users eg nurses, volunteers

d) no description of the derivation of the cohort

2) Selection of the non exposed cohort

a) drawn from the same community as the exposed cohort ��

b) drawn from a different source

c) no description of the derivation of the non exposed cohort


a) secure record (eg surgical records) ��

b) structured interview ��

c) written self report

d) no description

4) Demonstration that outcome of interest was not present at start of study

a) yes ��

b) no

Comparability

1) Comparability of cohorts on the basis of the design or analysis

a) study controls for _____________ (select the most important factor) ��

b) study controls for any additional factor �� (This criteria could be modified to indicate specific


Outcome

1) Assessment of outcome

a) independent blind assessment ��

b) record linkage ��

c) self report

d) no description

2) Was follow-up long enough for outcomes to occur

a) yes (select an adequate follow up period for outcome of interest) ��

b) no

3) Adequacy of follow up of cohorts

a) complete follow up - all subjects accounted for ��

b) subjects lost to follow up unlikely to introduce bias - small number lost - > ____ % (select an

adequate %) follow up, or description provided of those lost) ��

c) follow up rate < ____% (select an adequate %) and no description of those lost

d) no statement

Page 17 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from




(adapted for cross-sectional studies)

Selection: (Maximum 3 stars)

1) Representativeness of the sample:

a) Truly representative of the average in the target population. * (all subjects or random sampling)

b) Somewhat representative of the average in the target population. * (non-random sampling)

c) Selected group of users.

d) No description of the sampling strategy.

2) Sample size:

a) Justified and satisfactory. *

b) Not justified.

3) Non-respondents:

a) Comparability between respondents and non-respondents’ characteristics is established, and

the response rate is satisfactory. *

b) The response rate is unsatisfactory, or the comparability between respondents and non-

respondents is unsatisfactory.

c) No description of the response rate or the characteristics of the responders and the non-

responders.

Control of confounders: (Maximum 2 stars)

1) The subjects in different outcome groups are comparable, based on the study design or analysis.

Confounding factors are controlled.

a) The study controls for the most important factor (select one). *

b) The study control for any additional factor. *

Outcome: (Maximum 4 stars)

1) Assessment of the outcome:

a) Independent blind assessment. **

b) Record linkage. *

c) Self report.

d) No description.

2) Statistical test:

a) The statistical test used to analyze the data is clearly described and appropriate, and the

measurement of the association is presented, including confidence intervals and the probability level (p

value). *

b) The statistical test is not appropriate, not described or incomplete.

3) Ascertainment of the outcome measurement:

a) Validated measurement tool.*

b) Non-validated measurement tool, but the tool is available or described.

c) No description of the measurement tool.

Page 18 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



PRISMA-P (Preferred Reporting Items for Systematic review and Meta-Analysis Protocols) 2015 checklist: recommended items to

address in a systematic review protocol

Section and topic Item

No

Checklist item Page #

ADMINISTRATIVE INFORMATION

Title:

Identification 1a Identify the report as a protocol of a systematic review 1

Update 1b If the protocol is for an update of a previous systematic review, identify as such -

Registration 2 If registered, provide the name of the registry (such as PROSPERO) and registration number 3

Authors:

Contact 3a Provide name, institutional affiliation, e-mail address of all protocol authors; provide physical mailing address of corresponding author 1

Contributions 3b Describe contributions of protocol authors and identify the guarantor of the review 12

Amendments 4 If the protocol represents an amendment of a previously completed or published protocol, identify as such and list changes; otherwise, state

plan for documenting important protocol amendments

-

Support:

Sources 5a Indicate sources of financial or other support for the review 12

Sponsor 5b Provide name for the review funder and/or sponsor 12

Role of sponsor

or funder

5c Describe roles of funder(s), sponsor(s), and/or institution(s), if any, in developing the protocol 12

INTRODUCTION

Rationale 6 Describe the rationale for the review in the context of what is already known 5-6

Objectives 7 Provide an explicit statement of the question(s) the review will address with reference to participants, interventions, comparators, and outcomes

(PICO)

6

METHODS

Eligibility criteria 8 Specify the study characteristics (such as PICO, study design, setting, time frame) and report characteristics (such as years considered,

language, publication status) to be used as criteria for eligibility for the review

6-7

Information sources 9 Describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other grey literature

sources) with planned dates of coverage

7-8

Search strategy 10 Present draft of search strategy to be used for at least one electronic database, including planned limits, such that it could be repeated 7-8,

Table 1

Study records:

Page 19 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960

on April 20, 2020 by guest. Protected by copyright. http://bmjopen.bmj.com/ BMJ Open: first published as 10.1136/bmjopen-2016-015633 on 14 February 2017. Downloaded from



Data

management

11a Describe the mechanism(s) that will be used to manage records and data throughout the review 8-9

Selection

process

11b State the process that will be used for selecting studies (such as two independent reviewers) through each phase of the review (that is,

screening, eligibility and inclusion in meta-analysis)

8-9

Data collection

process

11c Describe planned method of extracting data from reports (such as piloting forms, done independently, in duplicate), any processes for obtaining

and confirming data from investigators

9

Data items 12 List and define all variables for which data will be sought (such as PICO items, funding sources), any pre-planned data assumptions and

simplifications

9

Outcomes and

prioritization

13 List and define all outcomes for which data will be sought, including prioritization of main and additional outcomes, with rationale 9

Risk of bias in

individual studies

14 Describe anticipated methods for assessing risk of bias of individual studies, including whether this will be done at the outcome or study level,

or both; state how this information will be used in data synthesis

9

Data synthesis 15a Describe criteria under which study data will be quantitatively synthesised 10

15b If data are appropriate for quantitative synthesis, describe planned summary measures, methods of handling data and methods of combining

data from studies, including any planned exploration of consistency (such as I2, Kendall’s τ)

10

15c Describe any proposed additional analyses (such as sensitivity or subgroup analyses, meta-regression) 10

15d If quantitative synthesis is not appropriate, describe the type of summary planned 10

Meta-bias(es) 16 Specify any planned assessment of meta-bias(es) (such as publication bias across studies, selective reporting within studies) 10-11

Confidence in

cumulative evidence

17 Describe how the strength of the body of evidence will be assessed (such as GRADE) 10

Page 20 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960

on April 20, 2020 by guest. Protected by copyright. http://bmjopen.bmj.com/ BMJ Open: first published as 10.1136/bmjopen-2016-015633 on 14 February 2017. Downloaded from



Prevalence and patterns of congenital heart diseases in Africa: a systematic review and meta-analysis protocol

Journal: BMJ Open

Manuscript ID bmjopen-2016-015633.R1

Article Type: Protocol

Date Submitted by the Author: 18-Jan-2017

Complete List of Authors: Tankeu, Aurel; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Bigna, Jean Joel; Centre Pasteur of Cameroon, Epidemiology and Public Health Nansseu, Jobert Richie; Mother and Child Centre, Chantal Biya Foundation, Sickle cell unit Aminde, Leopold; Clinical Research Education, Networking & Consultancy (CRENC), Douala and Nguti District Hospital,

Danwang, Celestin; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Mazou, Temgoua Ngou ; Faculty of Medecine and Biomedical Sciences, Internal medicine and specialities Noubiap, Jean Jacques; Edea Regional Hospital, Internal Medicine Unit

<b>Primary Subject Heading</b>:

Cardiovascular medicine

Secondary Subject Heading: Epidemiology

Keywords: Congenital heart disease < CARDIOLOGY, Africa, Heart defects, cardiac malformation


BMJ Open on A

pril 20, 2020 by guest. Protected by copyright.

http://bmjopen.bm

j.com/

BM

J Open: first published as 10.1136/bm

jopen-2016-015633 on 14 February 2017. D

ownloaded from



1

Prevalence and patterns of congenital heart diseases in Africa: a systematic

review and meta-analysis protocol

Aurel T. Tankeu1, Jean Joel R. Bigna

2,3, Jobert Richie N. Nansseu

4,5, Leopold Ndemnge

Aminde6, Celestin Danwang

7, Temgoua Ngou Mazou

1, Jean Jacques N. Noubiap

8*

1. Department of Internal Medicine and Specialties, Faculty of Medicine and Biomedical

Sciences, Yaoundé, Cameroon

2. Department of Epidemiology and Public Health, Centre Pasteur of Cameroon, Yaoundé,

Cameroon

3. Faculty of Medicine, University of Paris Sud XI, Le Kremlin Bicêtre, France

4. Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of

Yaoundé 1, Yaoundé, Cameroon

5. Sickle Cell Disease Unit, Mother and Child Centre of the Chantal Biya Foundation,

Yaoundé, Cameroon

6. Faculty of Medicine & Biomedical Sciences, School of Public Health, The University of

Queensland, Brisbane, Queensland, Australia

7. Department of Surgery and Specialties, Faculty of Medicine and Biomedical Sciences,

University of Yaoundé 1, Yaoundé, Cameroon

8. Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape

Town, South Africa

E-mail addresses: ATT: [email protected]; JJRB: [email protected]; JRNN:

[email protected]; LNA: [email protected]; CD: [email protected];

TNM: [email protected]; JJNN: [email protected]

*Corresponding author: Dr. Jean Jacques N. Noubiap. Department of Medicine, Groote

Schuur Hospital and University of Cape Town, 7295, Cape Town, South Africa.

[email protected]

Page 1 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



2

Abstract

Introduction

Congenital heart diseases (CHD) are common causes of cardiovascular morbidity and

mortality among young children and adolescents living in Africa. Accurate epidemiological

data are needed in order to evaluate and improve preventive strategies. This review aims to

determine the prevalence of CHD and their main patterns in Africa.


This systematic review and meta-analysis will include cross-sectional, case–control and

cohort studies of populations residing inside African countries, which have reported the

prevalence of CHD; confirmed by an echocardiographic examination, and/or describing

different patterns of these abnormalities in Africa. Relevant abstracts published without

language restriction from January 1st, 1986 to December 31

st 2016 will be searched in

PubMed, Exerpta Medica Database and online African journals as well as references of

included articles and relevant reviews. Two review authors will independently screen, select

studies, extract data and assess the risk of bias in each study. The study-specific estimates will

be pooled through a random-effects meta-analysis model to obtain an overall summary

estimate of the prevalence of CHD across studies. Clinical and statistical heterogeneity will be

assessed, and we will pool studies judged to be clinically homogenous. On the other hand,

statistical heterogeneity will be evaluated by the χ2 test on Cochrane’s Q statistic. Funnel-

plots analysis and Egger’s test will be used to detect publication bias. Results will be

presented by geographic region (central, eastern, northern, southern and western Africa).

Ethics and dissemination

Page 2 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



3

The current study will be based on published data, and thus ethical approval is not required.

This systematic review and meta-analysis is expected to serve as a base which could help

estimating and evaluating the burden of these abnormalities on the African continent. The

final report of this study will be published in a peer-reviewed journal.

Review registration number

PROSPERO CRD42016052880.

Funding

None.

Page 3 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



4

Strengths and limitations of the study

• To the best of our knowledge, this will be the first systematic review on the topic of

Congenital heart diseases (CHD) to summarize available data on African continent.

• We will use powerful meta-analysis techniques to derive accurate estimates.

• A major possible limitation of this study could be the limited data with predominance of

hospital-based studies. Indeed, these studies may not reflect the true prevalence of CHD in

the general population, therefore overestimating these estimates.

• Another possible limitation may be heterogeneity of studies done on the topic in Africa.

Page 4 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



5

Introduction

Congenital heart disease or congenital heart defect (CHD) is a problem of the heart’s structure

and function present at birth, affecting heart or adjacent great blood vessels detected either at

the time of birth or detected later in life.1

2 Worldwide, CHD are the main heart diseases

found in children and constitute one of the major causes of infant mortality, particularly in

developing countries.2 3

They also represent the most common of all congenital malformations

accounting for more than 20% of perinatal deaths.4 5

Their estimate prevalence is eight cases

per 1,000 live births across the globe, representing approximately 1.35 million newborns each

year with CHD but these figures vary worldwide.2 For instance, the incidence of CHD in

different studies varies from about 4/1.000 to 50/1.000 live births and despite advances in

detection and treatment, congenital heart diseases accounts for 3% of all infant deaths and

46% of death from congenital malformations in developed countries such as USA.4-6

In

addition, these abnormalities can be life threatening in early childhood, and children born with

severe forms are at approximately 12 times higher risk of mortality in the first year of life.7

Thus, hundreds of thousands of children die each year from CHD, while millions more remain

in desperate need of treatment in the developing world.8 Since mortality and morbidity from

cardiac disease among children in developing countries are gaining recognition, there is a

need of summarized data on CHD in African continent. Africa is thought to have one of the

highest prevalence of heart diseases in children and young adults, including CHD but main

findings include evidence that the CHD burden is underestimated mainly due to the poor

outcome of African children with CHD.7 From a global point of view, the epidemiology of

these abnormalities is still unknown in Africa with few data on the topic. Reducing the

prevalence of these diseases is urgent and requires a real inventory of the premises of the

problem that would clarify the issue for more effective prevention strategies and improved

Page 5 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



6

management. In this context, we present the protocol for a systematic review and meta-

analysis to assess the prevalence and patterns of CHD in Africa.

Objective

This systematic review and meta-analysis aims to determine the prevalence of CHD and their

different patterns in Africa.

Review question

This review of studies published in the past 30 years, from 1st January 1986 to 31

st December

2016, should answer the following questions

1. What is the prevalence of CHD among African populations?

2. What are the different patterns of CHD in Africa?


Criteria for considering studies for the review

Inclusion criteria

We will include:

1. Cross-sectional, case–control or cohort studies of populations residing in African countries

reporting the prevalence of CHD in African countries or enough data to compute these

estimates, regardless of stillbirth.

Page 6 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



7

2. Studies describing the different patterns of CHD on the African continent.

Exclusion criteria

We will not consider:

1. Studies on congenital abnormalities involving the heart but not considered as CHD (Long

QT syndrome, congenital but functionless abnormalities of the heart, cardiomyopathies).

2. Studies conducted among populations of African origin residing outside Africa.

3. Studies in subgroups of participants selected on the basis of cardiac murmurs without

echocardiographic confirmation of CHD (e.g. suspected but non-confirmed CHD).

4. Studies including many pathologies in which it will not be possible to extract data

regarding CHD or studies reporting congenital abnormalities affecting many systems at time.

5. Letters, reviews, commentaries and editorials.

6. Studies lacking key data and/or explicit method description.

7. Duplicates: for studies published in more than one paper, the most comprehensive one

reporting the largest sample size will be considered.

8. Studies whose full data will not be accessible even after request from the authors.

Search strategy for identifying relevant studies

The search strategy will be implemented in two stages:

Bibliographic database searches

A. Relevant abstracts published without language restriction on the prevalence, incidence,

main etiologies and clinical features of CHD in Africa will be identified via searching

Page 7 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



8

PubMed, Exerpta Medica Database, and online African journals. The search will be limited to

studies published between January 1st, 1986 and December 31

st, 2016. Both text words and

medical subject heading terms will be used. Key search terms include: ‘congenital heart

defects’ or ‘congenital heart disease’ as well as the name of every known pattern of these

abnormalities. We will also use individual country names for the 54 African countries as

additional key search terms for more abstracts on the subject. Conference proceedings and

studies from grey literature of the study period will also be identified through databases and

checked. The main search strategy is shown in Table 1.

B. The abstracts of all eligible papers will be reviewed and full articles will be accessed

through PubMed, Exerpta Medica Database, Google Scholar, HINARI or journals’ websites.

Additionally, references of all relevant articles and reviews will be scrutinized for other

potential data sources, and their full texts will be accessed in a similar way. The authors


directly contacted to provide them. In case of no feedback from these authors, the


Searching for others sources

References of all relevant researches and review articles will be scrutinized for additional

potential data sources, and their full texts will be accessed in a similar way. Those authors


directly contacted via email to provide them. In case of no feedback from these authors, the


Selection of studies for inclusion in the review

Page 8 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



9

Assessment of eligible papers will be independently run by two authors using an assessment

guide to ensure that the selection criteria are reliably applied by all the team. They will screen

the titles and abstracts obtained from the searches and retrieve the full texts of potentially

eligible papers by at least one author. Thereafter, they will independently review the full text

of each potentially eligible study, compare their results and resolve any discrepancy by

discussion and consensus. If a decision is not reached, a third review author will be consulted

for arbitration.

Assessment of methodological quality and reporting of data

The Newcastle-Ottawa Scale (NOS) for assessing the quality of non-randomized studies in

meta-analyses will be used to assess the methodological quality and risk of bias for each study

(see online supplementary appendix S1).9 Risk of bias and quality scores will be presented in

a table.

Data extraction and management

A data extraction sheet will be used to collect information about the author, the country, the

year of publication, the study design, the sample size population, the mean/median age of the

population, the age range, the sex ratio, the prevalence of CHD as well as main patterns when

available. Where prevalence or information for calculating them (eg. sample size, number of

outcomes) are lacking, we will directly contact the corresponding author to request the

information. In case of multinational studies, we will separate the results to show the

prevalence and etiologies within individual countries. Where it will not be possible to

disaggregate the data by country, the study will be presented as one and the countries in which

the study was done will be shown.

Data synthesis and analysis

Page 9 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



10

Data will be analyzed using Stata software version 13 (Stata Corp V.13, Texas, USA). A

meta-analysis will be conducted for data obtained from studies in which CHD has the same

etiologies, Standard errors (SEs) for the study-specific estimates will first be determined from

the point estimate and the appropriate denominators, assuming a binominal distribution. Then,

the study-specific estimates will be pooled through a random-effects meta-analysis model to

obtain an overall summary estimate of the prevalence across studies, after stabilizing the

variance of individual studies using the Freeman-Tukey double arc-sine transformation (to

keep the effect of studies with extremely small or extremely large estimates).10

Heterogeneity

will be evaluated by the χ² test on Cochrane’s Q statistic11

which is quantified by I² values,

assuming that I² values of 25%, 50% and 75% represent low, medium and high heterogeneity

respectively.12

Where substantial heterogeneity will be detected, a subgroup analysis will be

performed to detect its possible sources using the following grouping variables: type of CHD,

consequences on cardiac hemodynamic, study setting (hospital vs community-based), age of

diagnosis, geographical area (central, eastern, northern, southern and western Africa), and

study quality. Difference between groups will be detected if p value < 0.05. Inter-rater

agreement for study inclusion will be assessed using Cohen’s κappa coefficient.13

Funnel

plots analysis and Egger’s test14

will be done to detect publication bias. Publication bias will

be confirmed if p value on Egger’s test < 0.10. Results will be presented by geographic region

(central, eastern, northern, southern and western Africa).

Presentation and reporting of results

The study selection process will be summarized using a flow diagram. Reasons for studies’

exclusion will be described. The report will follow the PRISMA (Preferred Reporting Items

for systematic review and Meta-analysis) Guidelines.15

Tables and forest plots will serve to

Page 10 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



11

summarize quantitative data where appropriate. We will examine prevalence and etiologies by

region, setting (hospital or community) and time period depending on the data available. We

plan to report on quality scores and risk of bias for each eligible study. This may be tabulated

and accompanied by narrative summaries.

Conclusion

CHD represent the second major cause of CVD morbidity and mortality among young

Africans. Their management is limited in Africa in an inadequate socio-economic

environment with insufficient technical platform and human resources. Moreover, the global

burden of these conditions is unknown on the continent. Therefore, it becomes urgent to

provide summarized recent and reliable data in order to help estimating the prevalence as well

as etiologies in Africa in other to highlight the importance of these abnormalities and the need

to reinforce of effective preventives strategies based on systematic screening of cardiac

abnormalities in the perinatal period. We hope that this review will help sensitizing health

care providers on the problem represented by CHD in Africa, assist and support the

implementation of new policies, practices and researches by providing insights into the

current situation and the true impact of CHD on African continent as well as shortcomings

that can guide future research around this topic.

Protocol and registration

The protocol for this review has been published in the PROSPERO International Prospective

Register of systematic reviews (http://www.crd.york.ac.uk/PROSPERO), registration number:

PROSPERO CRD42016052880

Page 11 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



12

Authors’ Contributions

ATT and JJNN conceived and designed the protocol. ATT drafted the manuscript. JJRB,

JRNN, LNA, CD, TNM and JJNN critically revised the manuscript for methodological and

intellectual content. JJNN is the guarantor of the review. All authors approved the final

version of this manuscript.

Competing interests

None.

Funding

This research received no specific grant from any funding agency in the public, commercial or

not-for-profit sectors.

Data sharing statement

No additional data are available.

References

1. Tantchou Tchoumi JC, Butera G, Giamberti A, et al. Occurrence and pattern of

congenital heart diseases in a rural area of sub-Saharan Africa. Cardiovasc J Afr.

2011;22(2):63–6.

2. Chelo D, Nguefack F, Menanga AP, et al. Spectrum of heart diseases in children: an

echocardiographic study of 1,666 subjects in a pediatric hospital, Yaounde, Cameroon.

Cardiovasc Diagn Ther. 2016;6(1):10–9.

3. Kouame BD, N’guetta-Brou IA, Kouame GSY, et al. Epidemiology of congenital

abnormalities in West Africa: Results of a descriptive study in teaching hospitals in

Abidjan: Cote d’Ivoire. Afr J Paediatr Surg. 2015;12(1):51–5.

Page 12 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



13

4. Sadowski SL. Congenital cardiac disease in the newborn infant: past, present, and future.

Crit Care Nurs Clin North Am. 2009;21(1):37–48.

5. Hoffman JIE, Kaplan S. The incidence of congenital heart disease. J Am Coll Cardiol.

2002;39(12):1890–900.

6. Chinawa JM, Eze JC, Obi I, et al. Synopsis of congenital cardiac disease among children

attending University of Nigeria Teaching Hospital Ituku Ozalla, Enugu. BMC Res

Notes. 2013;6:475.

7. Otaigbe BE, Tabansi PN. Congenital heart disease in the Niger Delta region of Nigeria:

a four-year prospective echocardiographic analysis. Cardiovasc J Afr. 2014;25(6):265–8.

8. Massoure PL, Roche NC, Lamblin G, et al. Cardiovascular disease in children in

Djibouti: a single-centre study. Pan Afr Med J. 2013;14:141.

9. Turner L, Boutron I, Hróbjartsson A, et al. The evolution of assessing bias in Cochrane

systematic reviews of interventions: celebrating methodological contributions of the

Cochrane Collaboration. Syst Rev. 2013;2:79.

10. Miller JJ. The Inverse of the Freeman – Tukey Double Arcsine Transformation. Am

Stat. 1978;32(4):138–138.

11. Cochran GW. The Combination of Estimates from Different Experiments. Biometrics

1954;10(1):101-29.

12. Huedo-Medina TB, Sánchez-Meca J, Marín-Martínez F, Botella J. Assessing

heterogeneity in meta-analysis: Q statistic or I2 index? Psychol Methods.

2006;11(2):193–206.

13. McHugh ML. Interrater reliability: the kappa statistic. Biochem Medica. 2012

15;22(3):276–82.

14. Egger M, Davey Smith G, Schneider M, et al. Bias in meta-analysis detected by a

simple, graphical test. Bmj 1997;315(7109):629-34.

15. Moher D, Liberati A, Tetzlaff J, et al. Preferred reporting items for systematic reviews and

meta-analyses: the PRISMA statement. Journal of clinical epidemiology

2009;62(10):1006-12.

Page 13 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



14

Table 1: Search strategy for PubMed

Search Search terms

#1 congenital heart OR heart defects OR heart murmur OR fallot OR ventricular

defect OR atrial defect OR septal defect OR great vessels transposition OR

foramen ovale OR single ventricle OR persistent ductus arteriosus OR dorv

OR avsd OR ASD OR VSD OR BAV OR d-tga OR aorta coarctation OR

hypoplastic heart OR total anomalous pulmonary venous connection OR

truncus arteriosus OR ebstein s abnormality OR tricuspid atresia OR cyanotic

heart OR non cyanotic heart OR mitral stenosis[tw] OR mitral

incompetence[tw] OR tricuspid incompetence[MeSH terms] OR tricuspid

stenosis[tw] OR pulmonary stenosis[tw] OR pulmonary incompetence[tw]

OR aortic incompetence[tw] OR aortic stenosis[MeSH terms] OR heart

murmur[tw] OR Atrial septal defect[tw] OR Ventricular septal defect[tw] OR

Pulmonary atresia[tw] OR Aortic atresia[tw] OR echocardiography

abnormalities[tw] OR Fallot tetralogy[tw] OR aorta coarctation[tw] OR

cyanotic cardiac abnormalities[tw] OR atrioventricular septal defects[tw] OR

biscupid aortic valve[tw] OR double outlet right ventricle[tw] OR patent

ductus arteriosus[tw] OR single ventricle[tw] OR great arteries

transposition[tw] OR hypoplastic heart[tw] OR tricuspid atresia[tw] OR

Ebstein abnormality[tw] OR truncus arteriosus[tw] OR total anomalous

pulmonary venous connection[tw]

#2 (Africa* OR Algeria OR Angola OR Benin OR Botswana OR "Burkina Faso"

OR Burundi OR Cameroon OR "Canary Islands" OR "Cape Verde" OR

"Central African Republic" OR Chad OR Comoros OR Congo OR

Page 14 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



15

"Democratic Republic of Congo" OR Djibouti OR Egypt OR "Equatorial

Guinea" OR Eritrea OR Ethiopia OR Gabon OR Gambia OR Ghana OR

Guinea OR "Guinea Bissau" OR "Ivory Coast" OR "Cote d'Ivoire" OR

Jamahiriya OR Kenya OR Lesotho OR Liberia OR Libya OR Madagascar

OR Malawi OR Mali OR Mauritania OR Mauritius OR Mayotte OR Morocco

OR Mozambique OR Namibia OR Niger OR Nigeria OR Principe OR

Reunion OR Rwanda OR "Sao Tome" OR Senegal OR Seychelles OR "Sierra

Leone" OR Somalia OR "South Africa" OR “South Sudan” OR "St Helena"

OR Sudan OR Swaziland OR Tanzania OR Togo OR Tunisia OR Uganda OR

"Western Sahara" OR Zaire OR Zambia OR Zimbabwe OR "Central Africa"

OR "Central African" OR "West Africa" OR "West African" OR "Western

Africa" OR "Western African" OR "East Africa" OR "East African" OR

"Eastern Africa" OR "Eastern African" OR "North Africa" OR "North

African" OR "Northern Africa" OR "Northern African" OR "South African"

OR "Southern Africa" OR "Southern African" OR "sub Saharan Africa" OR

"sub Saharan African" OR "subSaharan Africa" OR "subSaharan African")

NOT ("guinea pig" OR "guinea pigs" OR "aspergillus niger")

#3 #1 AND #2

#4 # 3 Limits: : 1986/01/01 to 2016/12/31

Page 15 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from




CASE CONTROL STUDIES


Exposure categories. A maximum of two stars can be given for Comparability.

Selection

1) Is the case definition adequate?

a) yes, with independent validation

b) yes, eg record linkage or based on self reports

c) no description

2) Representativeness of the cases

a) consecutive or obviously representative series of cases

b) potential for selection biases or not stated

3) Selection of Controls

a) community controls

b) hospital controls

c) no description

4) Definition of Controls

a) no history of disease (endpoint)

b) no description of source

Comparability

1) Comparability of cases and controls on the basis of the design or analysis

a) study controls for _______________ (Select the most important factor.)

b) study controls for any additional factor (This criteria could be modified to indicate specific


Exposure


a) secure record (eg surgical records)

b) structured interview where blind to case/control status

c) interview not blinded to case/control status

d) written self report or medical record only

e) no description

2) Same method of ascertainment for cases and controls

a) yes

b) no

3) Non-Response rate

a) same rate for both groups

b) non respondents described

c) rate different and no designation

Page 16 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from




COHORT STUDIES


Outcome categories. A maximum of two stars can be given for Comparability

Selection

1) Representativeness of the exposed cohort

a) truly representative of the average _______________ (describe) in the community

b) somewhat representative of the average ______________ in the community

c) selected group of users eg nurses, volunteers

d) no description of the derivation of the cohort

2) Selection of the non exposed cohort

a) drawn from the same community as the exposed cohort

b) drawn from a different source

c) no description of the derivation of the non exposed cohort


a) secure record (eg surgical records)

b) structured interview

c) written self report

d) no description

4) Demonstration that outcome of interest was not present at start of study

a) yes

b) no

Comparability

1) Comparability of cohorts on the basis of the design or analysis

a) study controls for _____________ (select the most important factor)

b) study controls for any additional factor (This criteria could be modified to indicate specific


Outcome

1) Assessment of outcome

a) independent blind assessment

b) record linkage

c) self report

d) no description

2) Was follow-up long enough for outcomes to occur

a) yes (select an adequate follow up period for outcome of interest)

b) no

3) Adequacy of follow up of cohorts

a) complete follow up - all subjects accounted for

b) subjects lost to follow up unlikely to introduce bias - small number lost - > ____ % (select an

adequate %) follow up, or description provided of those lost)

c) follow up rate < ____% (select an adequate %) and no description of those lost

d) no statement

Page 17 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from




(adapted for cross-sectional studies)

Selection: (Maximum 3 stars)

1) Representativeness of the sample:

a) Truly representative of the average in the target population. * (all subjects or random sampling)

b) Somewhat representative of the average in the target population. * (non-random sampling)

c) Selected group of users.

d) No description of the sampling strategy.

2) Sample size:

a) Justified and satisfactory. *

b) Not justified.

3) Non-respondents:

a) Comparability between respondents and non-respondents’ characteristics is established, and

the response rate is satisfactory. *

b) The response rate is unsatisfactory, or the comparability between respondents and non-

respondents is unsatisfactory.

c) No description of the response rate or the characteristics of the responders and the non-

responders.

Control of confounders: (Maximum 2 stars)

1) The subjects in different outcome groups are comparable, based on the study design or analysis.

Confounding factors are controlled.

a) The study controls for the most important factor (select one). *

b) The study control for any additional factor. *

Outcome: (Maximum 4 stars)

1) Assessment of the outcome:

a) Independent blind assessment. **

b) Record linkage. *

c) Self report.

d) No description.

2) Statistical test:

a) The statistical test used to analyze the data is clearly described and appropriate, and the

measurement of the association is presented, including confidence intervals and the probability level (p

value). *

b) The statistical test is not appropriate, not described or incomplete.

3) Ascertainment of the outcome measurement:

a) Validated measurement tool.*

b) Non-validated measurement tool, but the tool is available or described.

c) No description of the measurement tool.

Page 18 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



PRISMA-P (Preferred Reporting Items for Systematic review and Meta-Analysis Protocols) 2015 checklist: recommended items to

address in a systematic review protocol

Section and topic Item

No

Checklist item Page #

ADMINISTRATIVE INFORMATION

Title:

Identification 1a Identify the report as a protocol of a systematic review 1

Update 1b If the protocol is for an update of a previous systematic review, identify as such -

Registration 2 If registered, provide the name of the registry (such as PROSPERO) and registration number 3

Authors:

Contact 3a Provide name, institutional affiliation, e-mail address of all protocol authors; provide physical mailing address of corresponding author 1

Contributions 3b Describe contributions of protocol authors and identify the guarantor of the review 12

Amendments 4 If the protocol represents an amendment of a previously completed or published protocol, identify as such and list changes; otherwise, state

plan for documenting important protocol amendments

-

Support:

Sources 5a Indicate sources of financial or other support for the review 12

Sponsor 5b Provide name for the review funder and/or sponsor 12

Role of sponsor

or funder

5c Describe roles of funder(s), sponsor(s), and/or institution(s), if any, in developing the protocol 12

INTRODUCTION

Rationale 6 Describe the rationale for the review in the context of what is already known 5-6

Objectives 7 Provide an explicit statement of the question(s) the review will address with reference to participants, interventions, comparators, and outcomes

(PICO)

6

METHODS

Eligibility criteria 8 Specify the study characteristics (such as PICO, study design, setting, time frame) and report characteristics (such as years considered,

language, publication status) to be used as criteria for eligibility for the review

6-7

Information sources 9 Describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other grey literature

sources) with planned dates of coverage

7-8

Search strategy 10 Present draft of search strategy to be used for at least one electronic database, including planned limits, such that it could be repeated 7-8,

Table 1

Study records:

Page 19 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from



Data

management

11a Describe the mechanism(s) that will be used to manage records and data throughout the review 8-9

Selection

process

11b State the process that will be used for selecting studies (such as two independent reviewers) through each phase of the review (that is,

screening, eligibility and inclusion in meta-analysis)

8-9

Data collection

process

11c Describe planned method of extracting data from reports (such as piloting forms, done independently, in duplicate), any processes for obtaining

and confirming data from investigators

9

Data items 12 List and define all variables for which data will be sought (such as PICO items, funding sources), any pre-planned data assumptions and

simplifications

9

Outcomes and

prioritization

13 List and define all outcomes for which data will be sought, including prioritization of main and additional outcomes, with rationale 9

Risk of bias in

individual studies

14 Describe anticipated methods for assessing risk of bias of individual studies, including whether this will be done at the outcome or study level,

or both; state how this information will be used in data synthesis

9

Data synthesis 15a Describe criteria under which study data will be quantitatively synthesised 10

15b If data are appropriate for quantitative synthesis, describe planned summary measures, methods of handling data and methods of combining

data from studies, including any planned exploration of consistency (such as I2, Kendall’s τ)

10

15c Describe any proposed additional analyses (such as sensitivity or subgroup analyses, meta-regression) 10

15d If quantitative synthesis is not appropriate, describe the type of summary planned 10

Meta-bias(es) 16 Specify any planned assessment of meta-bias(es) (such as publication bias across studies, selective reporting within studies) 10-11

Confidence in

cumulative evidence

17 Describe how the strength of the body of evidence will be assessed (such as GRADE) 10

Page 20 of 20


BMJ Open

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960



jopen.bmj.com

/B

MJ O


ebruary 2017. Dow

nloaded from


bmj open€¦ · for peer review only 1 prevalence and patterns of congenital heart diseases in...

Documents