Community Racial Composition and Hospitalization Among Patients Receiving In-Center Hemodialysis

Rationale & objective: Community racial composition has been shown to be associated with mortality in patients receiving maintenenance dialysis. It is unclear whether living in communities with predominantly Black residents is also associated with risk for hospitalization among patients receiving hemodialysis.

Study design: Retrospective analysis of prospectively collected data from a cohort of patients receiving hemodialysis.

Setting & participants: 4,567 patients treated in 154 dialysis facilities located in 127 unique zip codes and enrolled in US Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 5 (2010-2015).

Exposure: Tertile of percentage of Black residents within zip code of patients' dialysis facility, defined through a link to the American Community Survey.

Outcome: Rate of hospitalizations during the study period.

Analytic approach: Associations of patient-, facility-, and community-level variables with community's percentage of Black residents were assessed using analysis of variance, Kruskal-Wallis, or χ²/Fisher exact tests. Negative binomial regression was used to estimate the incidence rate ratio for hospitalizations between these communities, with and without adjustment for potential confounding variables.

Results: Mean age of study patients was 62.7 years. 53% were White, 27% were Black, and 45% were women. Median and threshold percentages of Black residents in zip codes in which dialysis facilities were located were 34.2% and≥14.4% for tertile 3 and 1.0% and≤1.8% for tertile 1, respectively. Compared with those in tertile 1 facilities, patients in tertile 3 facilities were more likely to be younger, be Black, live in urban communities with lower socioeconomic status, have a catheter as vascular access, and have fewer comorbid conditions. Patients dialyzing in communities with the highest tertile of Black residents experienced a higher adjusted rate of hospitalization (adjusted incidence rate ratio, 1.32; 95% CI, 1.12-1.56) compared with those treated in communities within the lowest tertile.

Limitations: Potential residual confounding.

Conclusions: The risk for hospitalization for patients receiving maintenance dialysis is higher among those treated in communities with a higher percentage of Black residents after adjustment for dialysis care, patient demographics, and comorbid conditions. Understanding the cause of this association should be a priority of future investigation.