Neighborhood Factors, Air Pollution, and Mortality Among Kidney Failure Patients: Exploring Differences by Race and...

Fine particulate matter (PM_2.5) is associated with increased mortality and disproportionately affects minoritized patients with kidney failure, particularly Black patients. Among patients with kidney failure, we tested whether neighborhood characteristics (racial and ethnic segregation, socioeconomic deprivation, and built environment) modified the association between PM_2.5 exposure and mortality, overall and by race and ethnicity.

Cohort study (2003-2019).

National registry for patients with kidney failure.

Annualized PM_2.5 concentrations (high, > 9 μg/m³), segregation scores (Theil's H method), deprivation scores (American Community Survey), and built environment factors (medically underserved areas [MUA] and urbanicity) by patients' residential ZIP code at dialysis initiation.

All-cause mortality.

We used multivariable Cox regression with shared state-level frailty to quantify whether neighborhood factors modify the association between PM_2.5 and mortality, overall and stratified by race and ethnicity.

High PM_2.5 (vs low) was differentially associated with mortality among patients with kidney failure residing in neighborhoods characterized by high segregation (adjusted hazard ratio [aHR], 1.17; 95% confidence interval [CI], 1.15-1.19; P _{interaction high vs low} < 0.001), high deprivation (aHR, 1.17; 95% CI, 1.15-1.19; P _{interaction high vs low} < 0.001), MUA (aHR, 1.15; 95% CI, 1.13-1.16; P _interaction = 0.005), and high-density urban (HDU) areas (aHR, 1.14; 95% CI, 1.12-1.15; P _interaction < 0.001). These differential associations were most prominent among Black patients ([high segregation: aHR, 1.25; 95% CI, 1.21-1.29; P _{interaction high vs low} = 0.006], [high deprivation: aHR, 1.26; 95% CI, 1.22-1.30; P _{interaction high vs low} < 0.001], [MUA: aHR, 1.22; 95% CI, 1.19-1.26; P _interaction = 0.02], [HDU areas: aHR, 1.23; 95% CI, 1.20-1.26; P _interaction < 0.001]).

Outdoor PM_2.5 may not reflect individual-level exposures.

High levels of PM_2.5 were associated with increased mortality risk among patients with kidney failure residing in neighborhoods characterized by high segregation, high deprivation, MUAs, and HDU areas, particularly among Black patients. Nephrologists should consider closer monitoring of patients, particularly those from minoritized groups who reside in these high-risk neighborhoods, to help mitigate the adverse effects of PM_2.5 and reduce related mortality.