Income disparities, segregation may account for survival differences in U.S. hemodialysis patients

Complex socioeconomic and residential factors may account for differences in survival between Black and White kidney failure patients, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The findings could help researchers design interventions to prolong patients' lives.

Among kidney failure patients on dialysis in the United States, Blacks tend to live longer than Whites with higher income. To investigate why, Paul Kimmel, MD (National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health) and his colleagues examined links between income inequality and residence with Black and White kidney failure patients' survival.

For their study, the researchers merged US Renal Data System information on kidney failure patients starting dialysis from 2000 through 2008 with Census Bureau Black and White race-specific average household income. The analysis included 589,036 patients. Average household income for Black and White patients was $26,742 and $41,922, respectively.

Among the major findings:
•Residence in areas with higher average household income was linked with improved survival.
•In White patients, income inequality was associated with mortality.
•In Black patients exclusively, residence in highly segregated areas was associated with increased mortality.

The findings revealed that while Black kidney failure patients with lower incomes have longer survival than Whites, Blacks experience greater mortality as residential segregation increases. The results indicate that Black kidney failure patients on dialysis are particularly susceptible to both gradients in income and residential segregation.

"Unknown factors such as socioeconomic issues and neighborhood characteristics may affect differential survival for Black kidney failure patients," said Dr. Kimmel. "Lower access to inexpensive, nutritional foods and quality dialysis physicians and facilities, as well as living environments which are unsafe or predispose to physical inactivity could play roles and need to be evaluated." He noted that interventions directed at neighborhoods with a high proportion of Black residents might improve dialysis patient outcomes.