Trends and regional disparities in hypoplastic left heart syndrome prevalence and mortality in the USA: a nationwide study

Hypoplastic left heart syndrome (HLHS) is a critical congenital heart that requires complex surgical and medical management. Despite recent clinical advances, population-level data on infant mortality trends related to HLHS remain limited. This study examines temporal patterns in HLHS-related infant mortality rates (HLHS-IMR), timing of death, interstate variation, and demographic disparities, along with updated prevalence estimates. We analyzed U.S national data from 2007 to 2021 using CDC-WONDER linked births/deaths database. HLHS-related infant mortality rates (HLHS-IMR), identified using ICD-10 code Q23.4, were calculated per 100,000 live births. Bivariate analyses estimated relative risks (RR) by sex, race, gestational age (GA), and state. We used Joinpoint regression to estimate annual percent changes (APC) and average annual percent change (AAPC). We assessed recent state-level prevalence data from the National Birth Defects Prevention Network (NBDPN) for two 5-year periods: 2012–2016 and 2016–2020. Among 59,117,761 live births, 3566 (0.006%) HLHS-related infant deaths were recorded. HLHS-IMR declined by 43% (7.4 to 4.2 per 100,000), with an AAPC of − 3.2% (95% CI, − 5.1, − 1.6; p < .01). Mortality declined more steeply after 2016 (APC − 6.5%; 95% CI, − 21.0, − 3.2). Most deaths (57%) occurred in the neonatal period. Black infants had higher mortality risk (RR 1.15; 95% CI, 1.05, 1.26), while Asian infants had lower risk (RR 0.61; 95% CI, 0.51, 0.73). Recent HLHS prevalence was approximately 1 in 3653 live births. Conclusion: National HLHS-IMR has declined significantly, likely reflecting improvements in early diagnosis and critical clinical care. However, persistent racial and geographic disparities exist, warranting further investigation.