Objective: To investigate the contribution of body mass index (BMI) to mortality over 11 years of follow-up in a prevalent sample of dialysis patients aged 60+.
Design: Multivariate Cox proportional hazards regression analysis.
Setting: Multicenter stratified random sample of black and white older chronic dialysis patients in a southeastern state.
Subjects: 316 patients on hemodialysis (HD) and peritoneal dialysis (PD).
Main outcome measure: Continued survival from baseline interview in 1988 to June 1999.
Results: Adjusting for age, primary diagnosis of diabetes, cardiovascular comorbidity, HD/PD therapy, and patient-reported functional impairment, the interaction of baseline BMI with race and gender was associated with older patients' risk of mortality. Black females, black males, and white males with higher BMI had a reduced risk of mortality, while no protective effect of higher BMI was found for white females. Patients with cardiovascular comorbidity and greater functional impairment at baseline had increased mortality risk. BMI was not significantly correlated with serum albumin or functional impairment.
Conclusion: BMI, a simple anthropometric measure that provides a marker of nutritional status, interacts with race and gender to predict long-term survival in older dialysis patients. The association of survival with dialysis adequacy, nutritional indicators, and cardiovascular status in black and white dialysis patients is an important area of study.