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 <= 2.5 mu m [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 7.8 mu g/m(3) 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.