Variation Over Time in Medical Conditions and Health Service Utilization ofChildren with Down Syndrome

Kelly Thomas, BSc (OT) (Hons), Jenny Bourke, MPH, Sonya Girdler, PhD, Ami Bebbington, BSc (Hons), Peter Jacoby, MSc,

and Helen Leonard, MBChB, MPH

Objectives To compare the prevalence of parent reported medical conditions and rates of health service utiliza-tion in school-aged children with Down syndrome in Western Australia in 1997 and 2004.Study designWe compared two cross-sectional surveys completed by parents of children with Down syndromeidentified from population-based sources in 1997 (n = 210) and 2004 (n = 208). Surveys collected information onfamily demographics, medical conditions, health issues, and service utilization. The analysis described medicalconditions in 2004 and compared frequencies in both years. Regression analyses compared medical conditionsand health utilisation in the two cohorts.Results In 2004, children with Down syndrome had greater odds of having a bowel condition (OR, 1.69; 95%, 1.16to 2.45; P = .01), were less likely to have a current problem due to their cardiac condition (OR, 0.32; 95% CI, 0.15 to0.68, P = .003), and demonstrated an overall reduction in episodic illnesses and infections. The use of GP services(incidence rate ratio [IRR] = 0.91; 95% CI, 0.83 to 1.00, P = .05) and combined medical specialist visits (IRR = 0.92;95% CI, 0.84 to 1.01; P = .09) were reduced in 2004, as were overnight hospital admissions (IRR = 0.60; 95% CI,0.37 to 0.96; P = .03) and length of stay (IRR = 0.33; 95% CI, 0.24 to 0.44; P < .001).Conclusions The health status of children with Down syndrome has varied over time with reductions in currentcardiac problems, episodic illnesses, and health service use. Research is now needed to investigate the impact ofthese changes on the overall health and quality of life of children and families living with Down syndrome. (J Pediatr2011;158:194-200).

See editorial, p 178 and relatedarticle, p 319

Children with Down syndrome are predisposed to an array of medical comorbidities that may present as ongoing healthissues and increase their risk of recurrent episodic illness and infections.1-7 It is likely that improvements in the medicalmanagement of these conditions has led to the reported increased rates of infant and child survival.8 These medical

improvements include surgical advances and management of congenital heart defects,9 improved accessibility to antibioticsand vaccinations, and changes in community and health professionals’ attitudes toward the treatment provided to peoplewith Down syndrome.10 With this progress in health management, it would be expected that further improvements in thehealth of children with Down syndrome might be seen over time.

Although data are limited, there is a growing body of research which suggests that children with Down syndrome have higherrates of health care utilization than their peers.7,11-13 However, to our knowledge, no literature has examined changes in thisservice utilisation over time and in particular the impact of changes in models of service delivery such as the demedicalization ofcare of children with intellectual disabilities.14

Although the benefits of improved medical management have been described in terms of survival,9,15 little research has as-sessed the change in pattern of comorbidities, or general health and frequency of illnesses in children with Down syndrome overtime. With the improvements of medical care andmore effective treatments early in life, it might be expected that children withDown syndrome would have fewer episodic illnesses and ongoing problems associated with their medical conditions. Further-

From the Department of Occupational Therapy (K.T.,S.G.), School of Exercise, Biomedical, and HealthSciences, Edith Cowan University, West Perth, Western

more, we predicted that with these reductions in illnesses, coupled with thechanges in models of service delivery, a decline in health service utilization mightbe seen. We used population-based data on children with Down syndrome inWestern Australia obtained at two different points to test these hypotheses.

Australia; and Telethon Institute for Child HealthResearch (K.T., J.B., A.B., P.J., H.L.) Centre for ChildHealth Research, The University of Western Australia,West Perth, Western Australia

Supported by the National Institutes of Health (grant5R01HD043100-05). The authors declare no conflicts ofinterest.

0022-3476/$ - see front matter. Copyright ª 2011 Mosby Inc.

All rights reserved. 10.1016/j.jpeds.2010.08.045

GP General practitioner

IRR Incidence rate ratio

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Methods

Using the same population data source (formerly DisabilityServices Commission and now the Intellectual Disability Ex-ploring Answers [IDEA] database16) as the sampling frame,questionnaires have been administered to Western Austra-lian families of children with Down syndrome in 1997 and2004 (Figure).17,18 In 1997, the study was restricted toschool-aged children and included birth years 1980 to 1991but in 2004 was extended to include birth years 1980 to2004. Response fractions for the two waves were 79.5% (210/264)17 and 73% (363/500),18 respectively. This analysisrestricted data to subjects who were school-aged in 2004, thatis, birth years 1987 to 2000 (n = 208), to ensure a comparableage sample to the 1997 cohort. Ethical approval for bothwaves of the study was granted by the Ethics Committee ofPrincess Margaret Hospital for Children and approval to linkthe two data sets was obtained from the Disability ServicesCommission.

The 1997 and 2004 questionnaires included similar ques-tions on family demographic characteristics, medical condi-tions, and health-related conditions experienced by theirchild. Questions relating to medical conditions asked if thechild with Down syndrome had ever had a certain medicalcondition, and, if so, was the condition considered a currentproblem or one requiring ongoing medical treatment. In ad-

Figure. Ascertainment of study cases.

dition, the questionnaires gathered information on healthservice utilization including type and frequency of healthcare professional visits over the previous 12 months.Prevalences of conditions in 1997 and 2004 were compared

using logistic regression, and poisson regression was used tocompare rates of episodic illnesses and medical service use.To account for overlap of children within the 1997 and2004 cohorts, regression analyses were conducted withina generalised estimating equation framework.19,20

Results

The characteristics of the 1997 cohort have previously beendescribed in detail.17 The mean age of the 2004 study subjectswas 11.7 years (range, 5.02 to 17.98); there were 90 femalesand 118 males.

Medical Conditions in the 2004 CohortSpecific medical conditions in school-aged children withDown syndrome in the 1997 cohort have been previously de-scribed.17 Less than half the children had cardiac and bowelconditions. More than half had ear conditions and morethan three quarters had eye conditions. The medical condi-tions in the 2004 cohort are shown in Table I for allchildren and by age group and sex. Almost half of childrenwere reported to have cardiac conditions, with the most

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Table I. Specific medical conditions in children with Down syndrome in 2004 by age group and sex

ConditionChildren reported to have thecondition n (%) of whole cohort

n (%) Children in each agegroup to have condition:

n (%) of Males and femalesto have condition

5 to 9 10 to 13 14 to 17 Male Female

Cardiac: any 95 (45.7) 38 (50.7) 29 (46) 28 (40) 51 (43.2) 44 (48.9)Ventricular septal defect 33 (15.9) 14 (18.7) 10 (15.9) 9 (12.9) 20 (16.9) 13 (14.4)Atrial septal defect 25 (12.0) 12 (16) 5 (7.9) 8 (11.4) 15 (12.7) 10 (11.1)Aventricular septal defect 16 (7.7) 6 (8) 5 (7.9) 5 (7.1) 8 (6.8) 8 (8.9)‘‘Hole in the heart’’ 11 (5.3) 5 (6.7) 4 (6.3) 2 (2.9) 5 (4.2) 6 (6.7)Patent ductus arteriosus 8 (3.9) 3 (4) 3 (4.8) 2 (2.9) 4 (3.4) 4 (4.4)Tetralogy of Fallot 2 (1.0) 1 (1.3) 0 (0) 1 (1.4) 1 (0.8) 1 (1.1)

Bowel: any 66 (31.7) 28 (37.3) 18 (28.6) 20 (28.6) 38 (32.2) 28 (31.1)Constipation 41 (19.7) 17 (22.7) 12 (19) 12 (17.1) 23 (19.5) 18 (20)Duodenal atresia 9 (4.3) 4 (5.3) 2 (3.2) 3 (4.3) 6 (5.1) 3 (3.3)Celiac disease 0 (0.0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0)Hirschsprung disease 0 (0.0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0)

Ear or hearing: any 123 (59.1) 45 (60) 38 (60.3) 40 (57.1) 79 (66.9) 44 (48.9)Glue ear 86 (41.3) 29 (38.7) 27 (42.9) 28 (40) 55 (46.6) 29 (32.2)Perforated ear drum 18 (8.7) 7 (9.3) 7 (11.1) 4 (5.7) 12 (10.2) 6 (6.7)Hearing loss 36 (17.3) 16 (21.3) 11 (17.5) 9 (12.9) 24 (20.3) 12 (13.3)

Eye or visual: any 140 (67.3) 47 (62.7) 39 (61.9) 54 (77.1) 75 (63.6) 65 (72.2)Short-sightedness 52 (25.0) 16 (21.3) 16 (25.4) 20 (28.6) 30 (25.4) 22 (24.4)Long-sightedness 45 (21.6) 15 (20) 16 (25.4) 14 (20) 25 (21.2) 20 (22.2)Strabismus 46 (22.1) 19 (25.3) 11 (17.5) 16 (22.9) 23 (19.5) 23 (25.6)Astigmatism 18 (8.6) 5 (6.7) 7 (11.1) 6 (8.6) 10 (8.5) 8 (8.9)Nystagmus 9 (4.3) 3 (4) 0 (0) 6 (8.6) 3 (2.5) 6 (6.7)Cataracts 6 (2.9) 3 (4) 1 (1.6) 2 (2.9) 1 (0.8) 5 (5.6)

Thyroid disease: any 27 (13.0) 7 (9.3) 10 (15.9) 10 (14.3) 13 (11) 14 (15.6)Hypothyroidism 22 (10.6) 5 (6.7) 8 (12.7) 10 (14.3) 10 (8.5) 13 (14.4)Hyperthyroidism 3 (1.4) 0 (0) 2 (3.2) 1 (1.4) 3 (2.5) 0 (0)

Musculoskeletal 74 (35.6) 21 (28) 24 (38.1) 29 (41.4) 36 (30.5) 38 (42.2)Atlantoaxial instability 9 (4.33) 2 (2.7) 4 (6.3) 3 (4.3) 6 (5.1) 3 (3.3)Flat feet 47 (22.6) 13 (17.3) 14 (22.2) 20 (28.6) 19 (16.1) 28 (31.1)Scoliosis 5 (2.4) 0 (0) 2 (3.2) 3 (4.3) 2 (1.7) 3 (3.3)Perthes disease 3 (1.44) 0 (0) 2 (3.2) 1 (1.4) 2 (1.7) 1 (1.1)

Respiratory 126 (60.0) 44 (58.7) 43 (68.3) 39 (55.7) 71 (60.2) 55 (61.1)Sleep apnea 39 (19.8) 16 (21.3) 17 (27) 6 (8.6) 21 (17.8) 18 (20)Asthma 42 (20.2) 16 (21.3) 16 (25.4) 10 (14.3) 25 (21.2) 17 (18.9)

Table III. Comparison of reporting of medicalcondition and associated current problem (orrequirement for treatment) in children with Downsyndrome in 2004 compared with 1997

Condition OR 95% CI P value

Medical condition: everCardiac 1.24 0.93 to1.66 .14Bowel 1.69 1.14 to 2.51 .01Ear 1.13 0.80 to 1.62 .48Eye 0.71 0.48 to 1.05 .06Thyroid 0.91 0.56 to 1.49 .71

Current problem associatedwith medical condition

Cardiac 0.32 0.15 to 0.68 .003Bowel 1.47 0.85 to 2.54 .17Ear 1.15 0.78 to 1.68 .48Eye 0.82 0.96 to 1.16 .79Thyroid 1.30 0.28 to 2.32 .10

*Adjusted for age and sex.

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common cardiac conditions being ventricular and atrialseptal defects. Bowel conditions were reported to be presentin just under one third of children. Duodenal atresia wasthe most commonly reported congenital bowel disorderoccurring in 9 (4.3%) cases. Approximately one in eightchildren had a thyroid condition. Sensory defects werealso reported with 17% of children with hearing loss and67% with visual impairments or other eye conditions. Earconditions and hearing impairment were more common inboys, but no statistically significant differences were apparentacross age groups or sex for cardiac, bowel, thyroid, or eyeconditions. Seventy-four (35.6%) children were reported tohave ever had a musculoskeletal condition. ‘‘Flat feet’’ wasreported most frequently and was more common amonggirls (c2 = 6.6, P = .01). Respiratory conditions werereported in two thirds of children. Sleep apnea was reportedin approximately 20%, as was asthma. No association wasfound between respiratory conditions and sex; however, sleepapnea was more prevalent in the 10- to 19-year-old agegroup (c2 = 7.89, P = .02).

Medical Conditions in 2004 Compared with 1997The frequencies of children ever having a medical conditionand having ongoing problems or requiring ongoing treat-

196

ment for their medical condition in 1997 and 2004 are shownin Tables II (available at www.jpeds.com) and III, whichoutline the likelihood of having a medical condition orongoing problems after adjusting for age and sex comparedwith 1997. School-aged children with Down syndrome in

Thomas et al

February 2011 ORIGINAL ARTICLES

2004 had greater odds (OR, 1.69; 95%, 1.14 to 2.51; P = .01)of having any bowel condition than children in 1997, evenafter adjusting for age and sex. Increased odds were seenfor duodenal atresia (OR, 1.17; 95% CI, 0.60 to 2.28; P =.64) as well as constipation (OR, 1.20; 95% CI, 0.77 to 1.86;P = .43). For the 2004 cohort, there was a reduced odds ofreporting of eye conditions (OR, 0.71; 95% CI, 0.48 to1.05; P = .06) but an increased odds for long-sightedness(OR, 1.65; 95% CI, 1.06 to 2.58; P = .03). Children in 2004had approximately 70% less likelihood of having a currentproblem due to their cardiac condition (OR, 0.32; 95% CI,0.15 to 0.68; P = .003, after adjustment for age and sexeffects). An overall reduction in the incidence rates ofepisodic illnesses and infections among children withDown syndrome was found in 2004 compared with 1997(Table IV). The greatest reductions were seen for episodesof tonsillitis incidence rate ratio (IRR) (0.56; 95% CI, 0.38to 0.83; P < .001, not adjusted) and ear infections (IRR,0.77; 95% CI, 0.62 to 0.95; P = .01, not adjusted). Whenthe change in frequency of episodic illnesses was stratifiedaccording to the presence of congenital heart disease, bothof these conditions were significantly reduced in both,except that ear infections were only significantly reduced inthose without a heart condition.

Health Service UtilizationThe rates of health service utilization in 2004 and 1997 arecompared in Table IV. The rate of general practitioner(GP) visits (IRR, 0.91; 95% CI, 0.83 to 1.00; P = .05)

Table IV. Episodic illnesses and utilization of medical and speheart disease

Children with acardiac defect

Episodic illnesses IRR 95% CI P value

Cold or flu 0.90 0.74 to 1.09 .27Tonsillitis 0.25 0.13 to 0.48 .00Pneumonia 0.20 0.06 to 0.69 .01Bronchitis 0.67 0.36 to 1.23 .19Ear infection 1.00 0.73 to 1.36 .99

General practitionerand specialist visitsGeneral practitioner visits 0.33 0.24 to 0.44 <.001Pediatrician 1.56 0.99 to 2.47 .06Cardiologist - - -ENT specialist 1.12 0.81 to 1.54 .501Disability specialist 0.78 0.49 to 1.26 .31Eye specialist 0.71 0.49 to 1.01 .06Audiologist 0.93 0.60 to 1.43 .7Podiatrist - - -Dentist 1.07 0.83 to 1.37 .63All specialist services

combined (excluding GP visits)0.96 0.85 to 1.09 .53

HospitalizationsDay admissions 1.54 0.88 to 2.69 .133Overnight admissions 0.54 0.30 to 0.99 .046Nights in hospital per admission 0.39 0.29 to 0.54 <.001

Variation Over Time in Medical Conditions and Health Service Ut

decreased in 2004. There was also a reduction in use ofdisability specialist services (IRR, 0.67; 95% CI, 0.47 to0.95; P = .026) and podiatry (IRR, 0.67; 95% CI, 0.50 to0.91; P = .01). Adjustment for age and sex effects was notnecessary as there was no issue of confounding or effectmodification with these variables. Overnight hospitaladmissions (IRR, 0.60; 95% CI, 0.24 to 0.44; P = .03) andthe total nights spent in hospital (IRR, 0.33; 95% CI, 0.24to 0.44; P # .001) both showed markedly decreasedincidence rates in 2004 compared with 1997. The latterparalleled but exceeded the reduction seen for these 2 yearsin the general population of Western Australian school-aged children (IRR, 0.88; 95% CI, 0.86 to 0.90, P < .001)for whom hospitalization rates were accessed usingdata from the Hospital Morbidity Data System.21

Hospitalization for respiratory conditions was associatedwith the greatest reduction in 2004 (IRR, 0.28; 95% CI, 0.09to 0.90; P < .001), with the average nights in hospitaldecreasing from approximately 5 in 1997 to 1.6 nights in2004. When health service utilization was stratified accordingto the presence of a cardiac defect, GP services still decreasedin those who had had a cardiac defect but actually increasedin those who had never had one, although still decreasedoverall. However total nights in hospital still decreased forboth groups. The frequency of surgical interventions wasreported in 1997 and 2004. The odds of having cardiac (OR,1.08; 95% CI, 0.88 to 1.32; P = .46), ENT (OR, 1.03; 95% CI,0.75 to 1.42; P = .84), bowel (OR, 1.71; 95% CI, 0.83 to 3.52;P = .14), and eye surgery (OR, 0.92; 95% CI, 0.58 to 1.46;P = .73) were comparable across years.

cialized services in 2004 compared with 1997 by congenital

Children without acardiac defect All children

IRR 95% CI P value IRR 95% CI P value

1.03 0.87 to 1.21 .72 0.92 0.81 to 1.04 .190.49 0.29 to 0.81 .005 0.56 0.38 to 0.83 <.0010.06 0.01 to 0.48 .01 0.90 0.31 to 2.57 .840.37 0.26 to 0.52 .00 0.80 0.52 to 1.23 .320.72 0.55 to 0.96 .02 0.77 0.62 to 0.95 .01

1.18 1.04 to 1.33 .01 0.91 0.83 to 1.00 .050.94 0.64 to 1.39 .76 0.96 0.72 to 1.28 .77- - - - - -

0.84 0.61 to 1.14 .26 1.12 0.89 to 1.42 .340.52 0.30 to 0.90 .02 0.67 0.47 to 0.95 .030.83 0.61 to 1.13 .24 0.97 0.76 to 1.22 .770.7 0.50 to 0.98 .04 0.80 0.61 to 1.04 .090.63 0.42 to 0.95 .03 0.67 0.50 to 0.91 .011.17 0.95 to 1.44 .14 1.13 0.96 to 1.33 .140.95 0.84 to 1.08 .45 0.92 0.84 to 1.01 .09

0.95 0.57 to 1.61 .856 1.20 0.81 to 1.76 .370.61 0.28 to 1.32 .211 0.60 0.37 to 0.96 .030.23 0.12 to 0.43 <.001 0.33 0.24 to 0.44 <.001

ilization of Children with Down Syndrome 197

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Discussion

We aimed to compare the prevalences of medical conditionsand rates of episodic illness in children with Down syndromein 1997 and 2004 to identify any variation in health statusover time. In addition, the study investigated whether therewere any changes in health care utilization that might haverelated to improved health status or changes in availabilityof services. We found a significant reduction in ongoing car-diac conditions, and bowel and thyroid conditions were re-ported to be associated with increased ongoing problems inthe later cohort. Moreover, the overall reduction in episodicillnesses in 2004 suggested an improvement in health and re-duction in illnesses in children with Down syndrome overtime. Health service utilization was somewhat consistentwith these results, showing a reduction in GP appointmentsfor those with congenital heart disease, and a significant re-duction in nights in hospital both for those with and thosewithout a heart condition.

Importantly, this study found a 70% reduction in reportedcurrent cardiac problems in 2004 compared with 1997. It istherefore likely that this later cohort may have benefited con-siderably from recent improvements in early surgery and thushad less ongoing cardiac comorbidity than the earlier cohort.Several studies highlight the changing survival profile of chil-dren with Down syndrome8,9,15 and attribute increased sur-vival mainly to advances in cardiac surgery and theimproved medical management of these conditions. It wasonly in the mid-eighties that surgical correction became anoption for infants with complex heart disease in WesternAustralia (personal communication, Dr Luigi D’Orsogna,July 7, 2010). However, until the Cardiac Surgery Unit wasopened at Princess Margaret Hospital in 2000, transfer byair to Melbourne, Victoria (3400 km away), was necessaryfor all but simple repairs. Thus, many of the older childrenin our earlier cohort may not have had the benefit of earlycardiac surgery. Routine echocardiography in the neonatalperiod has only been standard practice for the past decade.Therefore it is also possible that there may have been a delayin identifying cardiac disease for some children in the earliercohort. Our study suggests that for children with Down syn-drome, these changes in clinical practice have resulted notonly in improved survival but also improved health and bet-ter quality of life.

In keeping with their improved cardiac status, childrenwere also reported to have an overall reduction in episodic ill-nesses and infections and hospitalizations for respiratory in-fections in 2004 compared with 1997. This is plausible giventhe increased respiratory morbidity associated with congen-ital heart disease.22,23 Improved health could also be attrib-uted to greater access to, and effectiveness of, antibiotictreatments and vaccinations within the health care sys-tem.10,24,25 The reduction in episodic illnesses may also be re-flected in the use of GP services for those with a heartcondition, where there was also a significant reduction in2004. Our study would over all support the thesis that the

198

health of children with Down syndrome has improved in re-cent years and is unique in its use of population data to dem-onstrate this.Higher rates of ongoing problems or the requirement for

continued treatment for thyroid and bowel conditions werereported in 2004. Greater awareness and the possible recog-nition and identification of thyroid disease26 in later yearsmay also account for some of the increase in thyroid condi-tions requiring ongoing treatment. The ongoing bowel prob-lems may be associated with continued treatment forconstipation. In the 1997 data collection, celiac disease wasonly reported by two families (prevalence, 1%)17 and in the2004 data collection by none. As previously noted, in the ab-sence of active screening programs, such as those undertakenin clinical centres in the United States, where prevalence from3.2% to 10.3% have been reported,27-29 celiac disease couldbe underrecognized in Western Australia.Musculoskeletal and respiratory conditions were also in-

vestigated in 2004. However, as no such data were availablefor the 1997 cohort, comparisons could not be made. Muscu-loskeletal conditions, most frequently ‘‘flat feet,’’ were re-ported in over a third of children. Temporarily correctablewith orthotics, worn by over half of the affected children inour study (data not shown), flat feet is considered the mostcommonly occurring musculoskeletal condition in childrenwith Down syndrome.30 Although only a minor musculo-skeletal impairment, early identification and correctionshould be provided to children with Down syndrome to pre-vent subsequent biomechanical and postural problems.31

However, a reduction in podiatry services was also reportedin 2004, indicating that children with Down syndrome mayno longer be receiving the level of specialist services theyrequire. Atlantoaxial instability was diagnosed in 4.3% ofchildren by cervical spine radiography. These results arecomparably lower than previous studies.32,33 Radiographyis still recommended in those who are symptomatic, butguidelines published in 2001 also still recommended screen-ing during the preschool period.34 However, radiographs ofthe cervical spine in individuals with Down syndrome are dif-ficult to interpret, and controversy still remains in regard tothe screening and diagnosis of atlantoaxial instability.35 Sleepapnea was reported to occur in 20% of children with Downsyndrome in the 2004 cohort. These prevalences were lowerthan other studies.36,37 However, it is also possible that par-ents are underestimating the prevalence of sleep apnea andassuming that irregular breathing during sleep is normalfor children with Down syndrome.37

The use of both GP and, to a lesser extent, combined spe-cialist services, was decreased in 2004 compared with the ear-lier cohort. The latter may be partly a consequence of thephasing out of free specialist disability medical services inWestern Australia since 2002,38 which has presumably re-sulted in less access to such services by families of childrenwith Down syndrome. This is a concern when there hasnot necessarily been any decrease in the prevalence of theconditions that specialists such as audiologists and podia-trists are specifically targeting. For example, regular

Thomas et al

February 2011 ORIGINAL ARTICLES

screening and subsequent management of hearing impair-ments is important in facilitating chances of academic prog-ress and socialisation for children with Down syndrome.39

Therefore, a fall in the use, and probably a reduction inthe availability of audiologist and podiatry services overtime, may be a cause for concern for this population inWestern Australia.

With regard to the reduction in GP services, segregation bythe presence of a heart defect showed that this effect was lim-ited to those with a heart defect, and there was actually an in-crease in use in those without a heart defect. Thus, thisreduction could be seen as a positive indicator of the benefitsof more optimal management of congenital heart disease. Al-though the trends in hospitalizations mirror that of the gen-eral population of school-aged children, the decrease inovernight hospital admissions in children with Down syn-drome was greater, again possibly reflecting an improvementin health for children with Down syndrome. Specialist ser-vices, if provided outside the public system, may be affectedby socioeconomic factors and thus not necessarily be reflec-tive of medical need. Although specialist services within thepublic system have been phased out in relation to disability,there has been no parallel reduction in access to general prac-tice and in-patient hospital care. Given these conditions andthe nature of the Australian health care system, we thoughtthat it was a reasonable assumption to consider overnighthospital admissions and general practitioner appointmentsrather than specialist appointments as a barometer of healthstatus.

In interpreting the findings of this study, it is important toacknowledge that varied responses, given by parents in thequestionnaire due to the differing terminology they mayhave used, could have led to possible encoding errors. To in-crease the power to detect differences between 1997 and 2004event rates, we elected to include data about those childrenwhose families participated in both studies. Moreover, byperforming the regression analyses within a generalized esti-mating equations framework, we were able to prevent anysubsequent loss of data independence due to within-personcorrelations for children with repeated observations. Al-though there is some research describing health service utili-zation by children with Down syndrome,7,12,13 our study isthus unique in providing an insight into the changes in healthservice use over time, which until now have also been unex-plored.

The information provided in this study has important im-plications for parents, health care professionals, and educa-tion providers. A clear understanding of the comorbiditiesexperienced by children with Down syndrome and theknowledge that a reduction in ongoing cardiac problemsand improved health has occurred over time will assist par-ents in making informed decisions regarding future plansor possible terminations of pregnancy. This information isalso valuable to health care professionals, aiming to minimizedisability and facilitate development, functioning, and opti-mal quality of life for children with Down syndrome. Finally,this research contributes to the knowledge of medical service

Variation Over Time in Medical Conditions and Health Service Ut

utilization by this population and may assist in the planningand provision of disability services. n

The authors gratefully acknowledge the participation of families in theDown Syndrome NOW study and thank them for their ongoing contri-butions to the study. We also thank the Down Syndrome WA and staffat the Disability Services Commission for their ongoing assistance inthe study and Dr Luigi D’Orsogna for his insights into the changingclinical practice at Princess Margaret Hospital.

Submitted for publication May 4, 2010; last revision received Jul 16, 2010;

accepted Aug 25, 2010.

Reprint requests: Dr Helen Leonard, MBChB, MPH, Telethon Institute for Child

Health Research, PO Box 855, West Perth 6872, Western Australia. E-mail:

hleonard@ichr.uwa.edu.au

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Thomas et al

Table II. Distribution of reporting of medical conditionand associated current problem (or requirement fortreatment) in children with Down syndrome 1997 and2004

Conditionn (%) of childrenin 1997 cohort

n (%) of childrenin 2004 cohort

Medical condition: everCardiac 85 (40) 95 (45.7)Bowel 45 (21) 66 (31.7)Ear 121 (57) 123 (59.1)Eye 156 (75) 140 (67.3)Thyroid 29 (14) 26 (12.5)

Current problem associatedwith medical conditionCardiac 21 (25) 9 (4.3)Bowel 20 (44) 28 (13.5)Ear 68 (54) 71 (34.1)Eye 125 (81) 117 (56.2)Thyroid 18 (51) 24 (11.5)

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Variation Over Time in Medical Conditions and Health Service Utilization of Children with Down Syndrome 200.e1