RESUMEN
This study assessed the hypothesis that the clinic site of service socioeconomic status (SES) represents an unmeasured confounder for clinical outcome comparisons between dialysis clinics and provider types, using data from the federal pay-for-performance program for end-stage renal disease. A total of 6506 dialysis facilities were categorized by clinic SES status (rurality and poverty status). Clinics were then grouped by provider type (chain size and tax status). Lastly, performance penalties were determined by each of these classifications. Findings were that 7.4% of dialysis clinics could be classified as being in rural locations, and 20.6% could be classified as being in high-poverty locations. Large dialysis organizations served more rural (65%) and high-poverty areas (metropolitan, 69%; micropolitan, 75%; rural, 75%) compared to other providers (medium, small, hospital/university). For-profit providers accounted for a majority of dialysis clinics in rural areas (78%) and high poverty areas (metropolitan, 84%; micropolitan, 85%; rural, 90%). This study found that dialysis clinic performance penalties did vary by SES, with poorer outcomes observed for clinic locations with lower SES. This finding, along with the nonrandom distribution of provider types by SES status, suggests that clinic and provider location SES may need to be considered when comparing providers.