Association of Heart Failure and Pulmonary Hypertension Among Individuals with Congenital Heart Defects With or Without Coexisting Down Syndrome Open Access

Kapera, Olivia (Spring 2021)

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Background: Congenital heart defects (CHD) are the most common congenital defect in the U.S., accounting for 1% of annual births. CHD complications include pulmonary hypertension (P-HTN) and heart failure (HF). Individuals with CHD are also more likely to have Down syndrome (DS). Despite medical advancements, P-HTN and HF present particular challenges among those affected by CHD, and this association has not been well examined by presence or absence of co-occurring DS. The proposed study investigates if individuals with CHD with or without coexisting DS are at increased risk for P-HTN and/or HF. 

Methods: This a retrospective secondary data analysis of 22,499 CHD patients aged 1-64 years identified using ICD-9-CM codes from healthcare encounters that occurred between 1/1/2008-12/31/2013 from 11 clinical and/or administrative data sources. Multivariate logistic regression was used to assess adjusted relative risks (aRR) and 95% confidence intervals (CIs) of P-HTN without HF, and HF-without P-HTN, among patients with CHD grouped by DS status.

Results: Overall, 9.3% of individuals with CHD had DS in our analytic study sample. Among all CHD cases, 4.7% had P-HTN without HF, 21.2% had HF without P-HTN, and 0.6% had both P-HTN and HF. Among individuals with CHD and DS, 7.6% had P-HTN without HF, 9.9% had HF without P-HTN, and 5.7% had both P-HTN and HF. Our regression analysis showed a 23% lower risk of P-HTN without HF among those with CHD and DS compared to patients with CHD without DF (aRR=0.77; 95% CI: 0.59-1.00). On the contrary, we found a significantly increased risk of HF without P-HTN in patients with CHD and DS compared to those with CHD without DS (aRR=1.51; 95% CI: 1.04-2.18). We were unable to analyze the group with both P-HTN and HF due to small number of affected individuals.

Conclusions: We found that co-occurring DS among individuals with CHD can impact the development of P-HTN and HF overtime. Comorbidities, like cyanosis and atrial arrythmia, and sleep apnea may affect risk of P-HTN and HF for patients with CHD and co-occurring DS, and should be further explored. Future studies should aim at improved assessment of clinical variables and potential confounders.

Table of Contents



Congenital Heart Defects

Types of CHD and Classification

Prevalence of CHD

Health Complications in CHD

CHD and Pulmonary Hypertension

CHD and Sleep Apnea

Other Known Factors Associated with CHD

Down Syndrome (DS)

Sleep Apnea and DS

CHD and DS


Study Design

Data Sources

Study Population

Outcome Variables

Exposure Variable


CHD Anatomic Complexity





Geographic Distribution

Health Insurance

Sleep Apnea Status

Socioeconomic (SES) Proxies


Statistical Analysis

IRB and Ethical Considerations






Table 1.  Descriptive Characteristics of Patients with Congenital Heart Defects, 2008-2013 (N=22499)

Table 2.  Bivariate Analyses: Distribution of Covariate Percentages of Pulmonary Hypertension and/or Heart Failure for Patients with Congenital Heart Defects and Co-occurring Down Syndrome

Table 3. Unadjusted Analysis: Risk of Pulmonary Hypertension without Heart Failure, Heart Failure without Pulmonary Hypertension, and Both Pulmonary Hypertension and Heart Failure with Covariates for Patients with Congenital Heart Defects and Co-occurring Down Syndrome

Table 4. Adjusted Analysis: Risk of Pulmonary Hypertension without Heart Failure for Select Covariates for Patients with Congenital Heart Defects and Co-occurring Down Syndrome

Table 5. Adjusted Analysis: Risk of Heart Failure without Pulmonary Hypertension for Select Covariates for Patients with Congenital Heart Defects and Co-occurring Down Syndrome


Figure 1.  Analytic Dataset Construction


Appendix A.  ICD-9-CM Codes for Pulmonary Hypertension (P-HTN) (3 codes)

Appendix B.  ICD-9-CM Codes for Heart Failure (16 codes)

Appendix C: ICD-9-CM Codes for Down Syndrome (4 codes)

Appendix D.  ICD-9-CM Codes for Anatomic Complexity of Congenital Heart Defects

Appendix E: ICD-9-CM Codes for Sleep Apnea (5 codes)

Appendix F: ICD-9-CM Codes for Comorbidity Classification

Diabetes Mellitus (DM) Classification (64 codes)

Hyperlipidemia (5 codes)

Endocarditis (19 codes)

Atrial Arrhythmia (4 codes)

Cyanosis (2 codes)

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