Access to Care and the Incidence of End-Stage Renal Disease Due to Diabetes

OBJECTIVE: Low socioeconomic status (SES) is associated with an increased risk of end-stage renal disease (ESRD) due to diabetes. Because ESRD is a preventable complication of diabetes, the association with SES may be related to limited access to treatment. RESEARCH DESIGN AND METHODS: In this population-based ecological study, I examined the association between the incidence of ESRD attributed to diabetes and the proportion of hospitalizations with no insurance, Medicaid, or managed care insurance; residence in a primary care provider shortage area or rural area; and rate of hospitalizations for hyperglycemic complications, by ZIP code in California in 2001–2004. RESULTS: The incidence of ESRD attributed to diabetes was higher in ZIP codes with higher proportions of hospitalizations with no insurance (r = 0.45; P < 0.0001) or Medicaid (r = 0.69; P < 0.0001) and in ZIP codes with higher rates of hospitalizations for hyperglycemic complications (r = 0.27; P < 0.0001). The incidence was lower in ZIP codes with higher proportions of hospitalizations with managed care insurance (r = −0.37; P < 0.0001) and was lower in primary care provider shortage areas and rural locations. In contrast, there were only weak associations between measures of access to care and the incidence of ESRD attributed to polycystic kidney disease, a condition that is not treatable. CONCLUSIONS: The incidence of ESRD attributed to diabetes is strongly associated with area-based measures of access to care, suggesting that access to treatment partly mediates the association between SES and the incidence of ESRD.