Differences in Mortality Among Mexican-American, Puerto Rican, and Cuban-American Dialysis Patients in the United States

Background: The Hispanic ethnic group is heterogeneous, with distinct genetic, cultural, and socioeconomic characteristics, but most prior studies of patients with end-stage renal disease focus on the overall Hispanic ethnic group without further granularity. We examined survival differences among Mexican-American, Puerto Rican, and Cuban-American dialysis patients in the United States. Study Design: Prospective observational study. Setting & Participants: Data from individuals randomly selected for the End-Stage Renal Disease Clinical Performance Measures Project (2001 to 2005) were examined. Mexican-American (n = 2,742), Puerto Rican (n - 838), Cuban-American (n = 145), and Hispanic-other dialysis patients (n = 942) were compared with each other and with non-Hispanic (n = 33,076) dialysis patients in the United States. Predictors: Patient characteristics of interest included ethnicity/race, comorbidities, and specific available laboratory values. Outcomes: The major outcome of interest was mortality. Results: In the fully adjusted multivariable model, 2-year mortality risk was significantly lower for the Mexican-American and Hispanic-other groups compared with non-Hispanics (adjusted hazard ratio, 0.79; 95% confidence interval, 0.73 to 0.85; adjusted hazard ratio, 0.81; 95% confidence interval, 0.71 to 0.92, respectively). Differences in 2-year mortality rates within the Hispanic ethnic groups were statistically significant (P = 0.004) and ranged from 21% lower mortality in Mexican Americans to 3% higher mortality in Puerto Ricans compared with non-Hispanics. Limitations: Include those inherent to an observational study, potential ethnic group misclassification, and small sample sizes for some Hispanic subgroups. Conclusion: Mexican-American and Hispanic-other dialysis patients have a survival advantage compared with non-Hispanics. Furthermore, Mexican Americans, Cuban Americans, and Hispanic others had a survival advantage compared with their Puerto Rican counterparts. Future research should continue to examine subgroups within Hispanic ethnicity to understand underlying reasons for observed differences that may be masked by examining the Hispanic ethnic group as only a single entity. Am J Kidney Dis 53:647-657. (C) 2009 by the National Kidney Foundation, Inc.