Particulate Air Pollution and Progression to Kidney Failure With Replacement Therapy: An Advanced CKD Registry-Based Cohort Study in Taiwan.

Rationale & Objective Limited evidence concerns fine particulate matter (with aerodynamic diameter ≤ 2.5μm [PM2.5]) exposure and the risk for kidney failure with replacement therapy (KFRT). This study assessed whether PM2.5 exposure was associated with progression of chronic kidney disease (CKD) to KFRT. Study Design Prospective cohort study. Setting & Participants 6,628 adult patients with CKD were recruited from the Advanced CKD Program in Taiwan between 2003 and 2015. Exposure Satellite-based spatiotemporal models were used to calculate each individual's 1-year PM2.5 exposure before the date of enrollment into the Advanced CKD Program. Outcomes Time to KFRT (defined as initiation of maintenance hemodialysis, peritoneal dialysis, or kidney transplantation) and time to all-cause mortality. Analytical Approach Multivariable proportional hazard regression analyses were used to estimate the association of PM2.5 with KFRT and all-cause mortality. Restricted cubic splines were used to explore dose-response relationships. Results The study population included 6,628 adult patients with CKD who were aged 20 to 90 years. 941 KFRT events and 1,653 deaths occurred during follow-up. The adjusted HR for progression to KFRT was 1.19 (95% CI, 1.08-1.31) per 7.8μg/m3 greater PM2.5, an amount spanning the interquartile range. There was evidence of a dose-response relationship (adjusted HRs of 1.16 [95% CI, 0.90-1.51], 1.19 [95% CI, 0.94-1.52], and 1.42 [95% CI, 1.12-1.80] for low, medium, and high PM2.5 levels). There was no significant association between PM2.5 and all-cause mortality (adjusted HR, 1.01 [95% CI, 0.95-1.08]). Limitations Misclassification of PM2.5 exposure assessment and the potential for residual confounding. Conclusions Our findings suggest that long-term exposure to PM2.5 is associated with increased risk for progression to KFRT in patients with CKD.