Cardiovascular Disease Risk Prediction in Indigenous AustraliansELIZABETH LM BARR (MPH, PHD)

NATIONAL HEART FOUNDATION POST-DOC FELLOW

MENZIES SCHOOL OF HEALTH RESEARCH

Cardiac Care in the NT Annual Workshop

2017 is proudly supported by:

Overview

▪ Primary prevention of cardiovascular disease (CVD) in Indigenous Australians

▪ Limitations of CVD risk scores in Indigenous Australians

▪ Cardiovascular Risk in IndigenouS People (CRISP) Study

Cardiac Care in the NT Annual Workshop - June 2017

Primary prevention of cardiovascular disease in Indigenous Australians

Cardiovascular disease in Indigenous Australians

Cardiovascular disease (CVD) remains a major public health problem for Indigenous populations globally including Aboriginal and Torres Strait Islander Australians

Cardiac Care in the NT Annual Workshop - June 2017AIHW 2015

Primary prevention of CVD

Cardiac Care in the NT Annual Workshop - June 2017

CVD primary prevention largely focuses on management of well-established risk factors: smoking, high cholesterol, high blood pressure and diabetes

Two potential clinical scenarios for Indigenous Australians

Cardiac Care in the NT Annual Workshop - June 2017

Woman

▪ 35 years

▪ Systolic BP: 135 mmHg

▪ uACR: 25 mg/mmol

▪ Pre-diabetes

▪ Smoker

▪ TC: HDL ratio: 4.0 mmol/l

Man

▪ 43 years

▪ Systolic BP: 155 mmHg

▪ uACR: 20 mg/mmol

▪ Diabetes

▪ Non-smoker

▪ TC: HDL ratio: 6.0 mmol/l

LOW RISK FOR 5 YR CVD ?

Limitations of CVD risk scores in Indigenous Australians

Cardiovascular co-morbidities in Indigenous Australians

AIHW data show a much

greater overlap of diabetes,

kidney disease and CVD for

Indigenous Australians

Cardiac Care in the NT Annual Workshop - June 2017

Proportion of people with CVD, diabetes and chronic kidney disease (AIHW 2015)

Indigenous Australians

Non-Indigenous Australians

Diabetes and albuminuria strongly linked to the development of CVD

Longitudinal studies show strong associations of diabetes and related metabolic factors, and kidney disease with the development of CVD

Cardiac Care in the NT Annual Workshop - June 2017

CVD risk associated with traditional risk factors:DRUID follow-up

Cardiac Care in the NT Annual Workshop - June 2017Barr ELM et al. Diabetic Medicine 2017 (in press)

Low HDL

Cholesterol

Smoking High total

cholesterol

BP Diabetes

Adjusting for age and sex

6.4 (2.4 – 16.5)

CVD risk associated with abnormal glycaemia: DRUID follow-up study

Cardiac Care in the NT Annual Workshop - June 2017Barr ELM et al. Diabetic Medicine 2017 (in press)

Adjusted baseline age and sex

Impaired

fasting

glucose

Impaired

glucose

tolerance

DiabetesNormal

glycaemia

3.3 (0.7 – 16.3)

2.7(0.8 – 8.7)

6.4 (2.4 – 16.5)

CVD risk associated with other risk factors: DRUID follow-up study

Cardiac Care in the NT Annual Workshop - June 2017Barr ELM et al. Diabetic Medicine 2017 (in press)

Poor

diet Obesity

High CRP

Low income

Dyslipidaemia

Microalb

Macroalb

Adjusted baseline age and sex

Population

attributable risk %

for CVD in this

cohort:

- 32% Diabetes

- 21% Albuminuria

Coronary artery disease incidence underestimated in Indigenous Australians

Cardiac Care in the NT Annual Workshop - June 2017

Total cohort Women Men

Wang and Hoy. MJA 2015

Limitations of individual studies

▪ Individual studies have limited generalisability

▪Smaller studies have limited statistical power to assess risk among specific groups (eg. women and men, younger and older people, populations in urban and remote settings)

▪Comparison of study results between studies is limited by different methods and analyses

Cardiac Care in the NT Annual Workshop - June 2017

Can we improve current CVD risk scores for Indigenous Australians?

Cardiac Care in the NT Annual Workshop - June 2017

Cardiovascular Risk in IndigenouS People (CRISP) Study

What is the CRISP study?

▪ Individual-level meta-analysis combines participant study data

▪ Not aggregate meta-analysis which combines summary study results

▪ Create large epidemiological cohort of Indigenous Australians

▪ Many advantages!▪ Improves statistical power

▪ Consistent and standardize analysis

Cardiac Care in the NT Annual Workshop - June 2017

Study cohorts contributing data to CRISP

Northern Territory surveys

▪ Galiwin’ku Healthy Lifestyle Study

▪ Bathurst Island Renal Disease Studies (BIRDS)

▪ Darwin Region Urban Indigenous Diabetes (DRUID) Study

▪ Heart of the Heart Study

Cardiac Care in the NT Annual Workshop - June 2017

Study cohorts contributing data to CRISP

Studies in Western Australia and Queensland

▪ Perth Aboriginal Atherosclerosis Risk Study (PAARS)

▪ Well Persons Health Check (WPHC) study

Cardiac Care in the NT Annual Workshop - June 2017

~ 6,000 PARTICIPANTS

CRISP aims: Enhance the accuracy of absolute CVD risk assessment for Indigenous Australians

▪ To explore the associations of “non-traditional” risk factors

(abdominal obesity, metabolic disorders and albuminuria)

compared to “traditional” risk factors (smoking, cholesterol and

blood pressure) to mortality and CVD in Indigenous Australians

▪ To identify the profiles of individuals who are at high risk of CVD but

currently not identified as being at high risk with existing clinical

risk scores

▪ To analyse the accuracy of CVD risk scores currently recommended

for Indigenous Australians, and where possible, develop an

improved CVD risk score

Cardiac Care in the NT Annual Workshop - June 2017

CRISP study longitudinal follow-up

▪ Obtaining CVD outcomes over the period between baseline testing and current follow-up

▪ CVD outcomes obtained from state-based hospital databases and the National Death Index

Cardiac Care in the NT Annual Workshop - June 2017

FOLLOW-UP PERIOD

Baseline

surveys and

health

examinations

CVD

Hospitalisation

Deaths

2017Cohort 1 1994

Cohort 2 1998

Cohort 3 1998

Cohort 4 2001

Cohort 5 2003

Cohort 6 2008

CRISP study investigator collaboration

InvestigatorsElizabeth Barr Steve Guthridge

Louise Maple-Brown Christine Connors

Alan Cass Wendy Hoy

Joan Cunningham Pamela Bradshaw

Shawn Tatipata Peter Thompson

Julie Brimblecombe Lyn Dimer

Robyn McDermott Alex Brown

Kerin O’Dea Jonathan Shaw

Cardiac Care in the NT Annual Workshop - June 2017

Summary

▪ There is an overwhelming burden of diabetes and

albuminuria in CVD risk for Indigenous Australians

▪ Current CVD risk scores may not adequately

capture future CVD risk in Indigenous Australians

▪ CVD risk equations need to be evaluated using

Australian data to assess the effects of

albuminuria, diabetes and other related factors

on CVD risk in Indigenous Australians

Cardiac Care in the NT Annual Workshop - June 2017

Thank you

PRESENTATION AT THE CARDIAC CARE IN THE NT ANNUAL WORKSHOP

DARWIN, JUNE 2017

FUNDING

NATIONAL HEART FOUNDATION VANGUARD GRANT

NATIONAL HEART FOUNDATION POST-DOCTORAL FELLOWSHIP