Supplementary Material for: Association of U.S. Dialysis Facility Neighborhood Characteristics with Facility-Level Kidney Transplantation

Background: Improving access to optimal healthcare may depend on the attributes of neighborhoods where patients receive healthcare services. We investigated whether the characteristics of dialysis facility neighborhoods - where most patients with end-stage renal disease are treated - were associated with facility-level kidney transplantation. Methods: We examined the association between census tract (neighborhood)-level sociodemographic factors and facility-level kidney transplantation rate in 3,983 U.S. dialysis facilities where kidney transplantation rates were high. Number of kidney transplants and total person-years contributed at the facility level in 2007-2010 were obtained from the Dialysis Facility Report and linked to the census tract data on sociodemographic characteristics from the American Community Survey 2006-2010 by dialysis facility location. We used multivariable Poisson models with generalized estimating equations to estimate the link between the neighborhood characteristics and transplant incidence. Results: Dialysis facilities in the United States were located in neighborhoods with substantially greater proportions of black and poor residents, relative to the national average. Most facility neighborhood characteristics were associated with transplant, with incidence rate ratios (95% CI) for standardized increments (in percentage) of neighborhood exposures of: living in poverty, 0.88 (0.84-0.92), black race, 0.83 (0.78-0.89); high school graduates, 1.22 (1.17-1.26); and unemployed, 0.90 (0.85-0.95). Conclusion: Dialysis facility neighborhood characteristics may be modestly associated with facility rates of kidney transplantation. The success of dialysis facility interventions to improve access to kidney transplantation may partially depend on reducing neighborhood-level barriers.