A conditional Poisson analysis of fine particulate matter and U.S. Medicare hospitalization, 1999-2010, by individual-level chronic health conditions.
Citation:
Hoffman, S. AND L. Neas. A conditional Poisson analysis of fine particulate matter and U.S. Medicare hospitalization, 1999-2010, by individual-level chronic health conditions. 2017 Conference of the International Society for Environmental Epidemiology, Sydney, New South Wales, AUSTRALIA, September 24 - 28, 2017.
Impact/Purpose:
This is an abstract of recent work extending previous analyses of the effect of fine particulate matter on mortality to hospitalizations. This work makes a modest contribution to our growing understanding of sensitive populations.
Description:
Background/Aim: A previous analysis suggested that U.S. counties with higher county-level prevalence of chronic conditions had stronger associations of mortality with fine particulate matter (PM2.5). This study assesses the modification of the effect of PM2.5 on daily hospitalizations by selected individual-level chronic health conditions. Methods: Admissions to short-term, inpatient hospitals for Medicare enrollees aged 65 and older from 1999-2010 for non-accidental causes were extracted and grouped by chronic health condition (U.S. Centers for Medicare & Medicaid Services). Readmissions within three days of a discharge were considered an extension of the prior hospitalization. We obtained air quality data from the U.S. Environmental Protection Agency and temperature data from the U.S. National Climatic Data Center. Spatially, daily counts were aggregated by Core-Base Statistical Areas (CBSA) based on county of residence at hospitalization. Conditional Poisson regression was used to estimate CBSA-specific associations of hospitalization with PM2.5 at lag 1 conditioning on calendar month and day of week and adjusting for natural splines of current and lagged temperature (individual lags 1-3). These CBSA-specific effect estimates were combined using Bayesian pooling. Results: For 298 CBSAs with sufficient data, a 10 µg/m3 increment in PM2.5 at lag 1 was associated with a 0.30% increased hospitalization (95% Posterior Interval (PI) 0.21, 0.38). Enrollees with chronic health conditions were at slightly higher risk: lung cancer +0.39% (95% PI 0.13, 0.65); chronic heart failure +0.35% (95% PI 0.24, 0.45); and depression +0.34% (95% PI 0.23, 0.45). Conclusions: PM2.5 is associated with increased risk of hospitalization among all Medicare enrollees aged 65 and older. Enrollees with lung cancer, heart disease and depression are slightly more at risk of hospitalization on the day after exposure to higher levels of PM2.5. This abstract does not necessarily represent the views of the US EPA.