Association of short-term exposure to ambient PM2.5 with hospital admissions and 30-day readmissions in end-stage renal disease patients: population-based retrospective cohort study
Objectives To examine the effect of short-term exposure to ambient fine particulate matter (PM2.5) on all-cause, cardiovascular and respiratory-related hospital admissions and readmissions among patients receiving outpatient haemodialysis.
Design Retrospective cohort study. Setting Inpatient hospitalisation claims identified from the US Renal Data System in 530 US counties.
Participants All patients receiving in-centre haemodialysis between 2008 and 2014.
Primary and secondary outcome measures Risk of all-cause, cardiovascular and respiratory-related hospital admissions and 30-day all-cause and cause-specific readmission following an all-cause, cardiovascular, and respiratory-related discharges. Readmission risk was evaluated for early (1–7 days postdischarge) and late (8–30 days postdischarge) readmission time periods. Relative risk is expressed per 10 μg/m3 of PM2.5.
Results Same-day ambient PM2.5 was associated with increased hospital admission risk for cardiovascular causes (0.9%, 95% CI 0.2 to 1.7). Greater PM2.5-related associations were observed with 30-day readmission risk. Early-readmission risk was increased by 1.6%–1.8% following all-cause (1.6%, 95% CI 0.6% to 2.6%), cardiovascular (1.8%, 95% CI 0.4% to 3.2%) and respiratory (1.8%, 95% CI 0.4% to 3.2%) discharges; while late-readmission risk increased by 1.2%–1.3% following all-cause and cardiovascular discharges. PM2.5-related associations with readmission risk were greatest for certain cause-specific readmissions ranging 4.0%–6.5% for dysrhythmia and conduction disorder, heart failure, chronic obstructive pulmonary disease, other non-cardiac chest pain or respiratory syndrome and pneumonia. Following all-cause discharges, the cause-specific early-readmission risk was increased by 6.5% (95% CI 3.5% to 9.6%) for pneumonia, 4.8% (95% CI 2.3% to 7.4%) for dysrhythmia and conduction disorder, 3.7% (95% CI 1.4% to 6.0%) for heart failure and 2.7% (95% CI 1.2% to 4.2%) for other non-cardiac chest pain or respiratory syndrome-related causes.
Conclusions Daily ambient PM2.5 was associated with an increased risk of cardiovascular admissions and 30-day readmissions following cardiopulmonary-related discharges in a vulnerable end-stage renal disease population. In the first week following discharge, greater PM2.5-related risk of rehospitalisation was identified for some diagnoses.