Source-Apportioned Particulate Air Pollution and 30-day Readmissions Among Heart Failure Patients

Abstract

BACKGROUND AND AIM: Fine particulate air pollution (PM2.5) exposure is associated with increased risk of hospital readmissions. This study aims to determine if this association differs according to the attributable source of the PM2.5. METHODS: We used zero-inflated poisson mixed-effects models to associate source-apportioned PM2.5 with the number of 30-day readmissions after HF diagnosis. The study cohort included patients diagnosed with HF who had a hospital visit at a University of North Carolina Healthcare System facility between July 5, 2004, and December 31, 2010. The exposure was the annual average source-apportioned PM2.5 at the date of HF diagnosis. Patient zip code was included as a random effect and models were adjusted for year of diagnosis, sex, race, age, smoking status and 2010 census block group measures of urbanicity, percent receiving public assistance, median income, and median house value. PM2.5 was apportioned into the sources using a Chemical Mass Balance Gas Constrained-Iteration model. Results are presented as the percent change in number of expected readmissions per interquartile range increase in source-apportioned PM2.5 and the associated 95% confidence interval (CI). RESULTS: We observed associations with 30-day readmissions for gasoline (16.89%; 95% CI = 4.82-30.36), diesel (9.87%; 95% CI = 1.72-18.69), and secondary organic carbon (SOC; 20.44%; 95% CI = 8.29-33.95) PM2.5. Associations were greater for study participants in a census block group with an income below the median value. Associations were also greater for Black HF patients compared to white HF patients. CONCLUSIONS: Associations between 30-day readmissions and PM2.5 appear greatest for traffic and SOC-related sources which may be due to a combination of differential toxicity as well as the distribution of these sources amongst HF patients. This abstract does not necessarily represent the views or policies of the US Environmental Protection Agency. KEYWORDS: Heart failure, hospital utilization, particulate matter, air pollution