Exposure to particulate matter with a diameter of 2.5 microns (PM2.5) has been linked to chronic kidney disease, hospitalization, poor transplantation outcomes, and early death. Recent research finds that these air pollutants increase the risk for both fatal and nonfatal cardiovascular events in patients receiving hemodialysis. 

Using 2011-2016 data from the US Renal Data System, investigators identified 314,079 patients receiving in-center hemodialysis (51% aged 65 years or older). They calculated PM2.5 exposure using the zip code of the dialysis clinic attended by each patient. The median annual PM2.5 exposure was 8.7 µg/m3.

Each 1 µg/m3 increment in annual PM2.5 exposure was significantly associated with a 2% increased risk for cardiovascular events and a 2% increased risk for death from cardiovascular causes, Ana G. Rappold, PhD, of the US Environmental Protection Agency in Research Triangle Park, North Carolina, and colleagues reported in the American Journal of Kidney Diseases. A cardiovascular event included any emergency department visit or hospitalization for a cerebrovascular event, ischemic heart disease, hypertension, heart failure, cardiac arrest, or related events. Results were similar in sensitivity analyses excluding hypertension.


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The investigators found particularly strong associations between PM2.5 exposure and cardiovascular events and mortality  among older patients, Asians, and those with chronic obstructive pulmonary disease (COPD).

“Our findings add to the emerging evidence regarding the association between PM2.5 exposure and outcomes among [hemodialysis] patients and are consistent with previous results in this population,” the authors wrote.

A 2021 study published in the American Journal of Nephrology also found that older patients on dialysis who lived in areas with high PM2.5 had higher mortality risk. Each 10 μg/m3 increase in PM2.5 above the regulatory standard of 12 μg/m3 was significantly associated with a 38% increased risk of cardiovascular mortality. In 2020, investigators published findings in the Journal of the American Society of Nephrology showing that wildfires increase PM2.5 exposure and mortality risks in the hemodialysis population.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Xi Y, Richardson DB, Kshirsagar AV, et al. Association between long-term ambient PM2.5 exposure and cardiovascular outcomes among US hemodialysis patients. Am J Kidney Dis. Published online June 8, 2022. doi:10.1053/j.ajkd.2022.04.008

Feng Y, Jones MR, Chu NM, Segev DL, McAdams-DeMarco M. Ambient air pollution and mortality among older patients initiating maintenance dialysis. Am J Nephrol. 2021; 52: 217-227. doi:10.1159/000514233