Abstract Body (Do not enter title and authors here): Background:
Congenital heart disease (CHD) is the leading cause of birth defect-related deaths among infants in the US. While ambient particulate matter (PM) PM2.5 is a known cardiovascular risk factor, its effect on CHD patients remains unclear. This study examines the link between county-level PM2.5 and 1-year mortality risk following pediatric congenital heart surgery (CHS).
Methods
We conducted a retrospective cohort study using data from the Pediatric Cardiac Care Consortium (PCCC), a large US-based multi-institutional registry of interventions for CHD. We included patients with available identifiers, initial CHS, county information and birth between 1989 and 2003. We obtained sex, birth year, CHD severity, chromosomal abnormality and neighborhood socioeconomic status (nSES). PM2.5 concentrations at 1-km resolution across the US were derived using spatiotemporal ensemble models integrating machine learning algorithms. The data were assigned to county-level scale by geo-information provided by the US Census Bureau. We used Cox proportional hazards regression with shared frailty models to estimate the hazard of death considering state as a random effect.
Results
We included a total of 27,327 patients who were enrolled in PCCC after an initial CHS (47.3% females). Patients exposed to higher PM2.5 quintile were more likely to be born in early birth era (1990-1993) (p<0.01) and at low nSES (p<0.01). After adjusting for sex, birth era, CHD severity, chromosomal abnormality and nSES, the hazard of death in patients exposed to the highest vs lowest PM2.5 quintile was 1.33 (95%CI: 1.02-1.72, p=0.03). In addition, there was a linear dose-response relationship between PM2.5 exposure and 1-year mortality risk (P _{non-linearity}=0.90) with each 1 μg/m³ increase in monthly PM2.5 exposure associated with 2% increase in the 1-year post-discharge hazard of death (aHR: 1.02, 95%CI: 1.00-1.04, p=0.05) (Figure).
Conclusion
Higher PM2.5 levels were independently associated with increased risk of death after pediatric CHS. Improving environmental conditions may mitigate the adverse health effects of particulate matter exposure for patients with CHD.