MAJOR CONGENITAL HEART DEFECTS AMONG INFANTS IN TEXAS: REGIONAL VARIATION IN THE PREVALENCE AND PRENATAL DETECTION RATE AND PREDICTORS OF COST

Linh K. Nguyen, UTHealth School of Public Health

Abstract

Background: A better understanding of the prevalence, prenatal detection rate, and cost of major congenital heart defects (MCHD) is important to improve prenatal detection of MCHD and enhance resource management.

Objectives: To assess temporal and regional variation in the prevalence, prenatal detection rate, and cost of MCHD and to investigate the impact of prenatal detection on cost among Texas Medicaid insured infants.

Methods: We conducted a retrospective cohort study of Medicaid insured infants born in Texas with MCHDs who were followed for one year after birth comprising: Hypoplastic left heart syndrome (HLHS), Tetralogy of Fallot (ToF), “Isolated” Coarctation of the Aorta (CoA), Simple or complete Transposition of the Great Arteries (d-TGA), and balanced Atrioventricular Septal Defect (AVSD). The study used a linked data set of the Texas Medicaid administrative data and the Texas Vital Records during 2010-2014. The geographic unit used to measure variation was the health referral region (HRR). We measured means and variation in the prevalence, prenatal detection rate (PDR) and cost by HRR and type of defect. The t-test and Chi-square tests were used to assess the differences between study groups for continuous variable and binary variables, respectively. The Cochrane-Armitage test was performed to detect a linear trend of prevalence and PDR during 2010-2014. Multilevel generalized linear model regression was conducted to assess variation in prevalence, prenatal detection rate and cost across the regions. Maps showing differences across Texas HRRs were created using ArcGIS Mapping software. We also investigated the impact of prenatal detection on total cost of MCHD using multivariable regression models, controlling for characteristics of infants and mothers.

Results: Our study found a 5-year pooled prevalence of 12.89/10,000 infants and a significantly increasing trend during 2010-2014. Prevalence of HLHS was 2.303, d-TGA – 1.676, CoA – 3.418, ToF – 3.475 and AVSD – 2.026 per 10,000 infants during the study period. The five-year PDR was 36.3%, increased from 29.74% in 2010 to 36.30% in 2014. Overall, PDR was highest for HLHS (59.6%) and lowest for d-TGA (26.35%). Our study found total cost, facility cost and professional cost averaged at $253,774.1 (SD = 292,666.9), $217,769.1 (SD = 266,312.3) and $36,005 (SD = 36,748.8), respectively. Health care expenses were above one million dollars in 2.4% of the babies. Infants with HLHS incurred the highest cost of care ($504,045.9 ± 404,606). Regarding the economic impact of prenatal detection on cost of MCHD, we found that infants whose MCHD was detected prenatally had on average $58,346 more in costs compared with their counterparts. The type of MCHD was a strong predictor of cost. When prenatal detection and type of defect were factored into the variation in cost, the infant’s social and clinical characteristics including sex, gestational age, NICU admission and number of episodes of major cardiac surgery were not associated with increased resource utilization. Prevalence, PDR and total cost of MCHD exhibited considerable variation across Texas regions.

Conclusion: Our study demonstrated an increasing trend in the prevalence and PDR of MCHDs during 2011-2014 and a substantial variation in prevalence, PDR and cost across Texas HRRs. Our study found a higher cost of care during the first year of life in babies with MCHD having prenatal detection and treatment of the condition.