Health-related quality of life and associated outcomes among hemodialysis patients of different ethnicities in the United States: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Abstract

Background: In the United States, an association between mortality risk and ethnicity has been observed among hemodialysis patients. This study was developed to assess whether health-related quality of life (HRQOL) scores also vary among patients of different ethnic backgrounds. Associations between HRQOL and adverse dialysis outcomes (ie, death and hospitalization) also were assessed for all patients and by ethnicity.

Methods: Data are from the Dialysis Outcomes and Practice Patterns Study for 6,151 hemodialysis patients treated in 148 US dialysis facilities who filled out the Kidney Disease Quality of Life Short Form. We determined scores for three components of HRQOL: Physical Component Summary (PCS), Mental Component Summary (MCS), and Kidney Disease Component Summary (KDCS). Patients were classified by ethnicity as Hispanic and five non-Hispanic categories: white, African American, Asian, Native American, and other. Multiple linear regression models were used to estimate differences in HRQOL scores among ethnic groups, using whites as the referent category. Cox regression models were used for associations between HRQOL and outcomes. Regression models were adjusted for sociodemographic variables, delivered dialysis dose (equilibrated Kt/V), body mass index, years on dialysis therapy, and several laboratory/comorbidity variables.

Results: Compared with whites, African Americans showed higher HRQOL scores for all three components (MCS, PCS, and KDCS). Asians had higher adjusted PCS scores than whites, but did not differ for MCS or KDCS scores. Compared with whites, Hispanic patients had significantly higher PCS scores and lower MCS and KDCS scores. Native Americans showed significantly lower adjusted MCS scores than whites. The three major components of HRQOL were significantly associated with death and hospitalization for the entire pooled population, independent of ethnicity.

Conclusion: The data indicate important differences in HRQOL among patients of different ethnic groups in the United States. Furthermore, HRQOL scores predict death and hospitalization among these patients.