Association of ethnicity and survival in peritoneal dialysis: a cohort study of incident patients in Brazil.

ABSTRACT

BACKGROUND: There are no available epidemiologic studies about the impact of ethnicity on outcomes of patients treated with peritoneal dialysis (PD) in South America. This study aims to assess the effect of ethnicity on the mortality of incident PD patients in Brazil. STUDY DESIGN: Prospective observational cohort study of incident patients treated with PD. SETTINGS & PARTICIPANTS: Patients 18 years or older who started PD therapy between December 2004 and October 2007 in 114 Brazilian dialysis centers. PREDICTORS Self-reported ethnicity defined by the Brazilian Institute of Geography and Statistics as black and brown versus white patients and baseline demographic, socioeconomic, clinical, and laboratory data were collected at baseline. OUTCOME: Mortality, using cumulative mortality curves in which kidney transplantation and transfer to hemodialysis therapy were treated as competing end points. Multivariate Cox proportional hazards analysis was used to adjust for gradually more potential explanatory variables, censored for kidney transplantation and transfer to hemodialysis therapy. Analyses were performed for all patients, as well as stratified for elderly (aged ≥65 years) and nonelderly patients. RESULTS: 1,370 patients were white, 516 were brown, and 273 were black. The competing-risk model showed higher mortality in white patients compared with black and brown patients. With white patients as the reference, Cox proportional hazards analysis showed a crude HR for mortality of 0.77 (95% CI, 0.56-1.05) for black and 0.74 (95% CI, 0.59-0.94) for brown patients. After adjusting for potential explanatory factors, HRs were 0.67 (95% CI, 0.48-0.95) and 0.77 (95% CI, 0.43-1.01), respectively. The same results were observed in elderly and nonelderly patients. LIMITATIONS: Ethnicity was self-determined and some misclassification might have occurred. CONCLUSIONS: Black and brown Brazilian incident PD patients have a lower mortality risk compared with white patients.