Background: Previous studies of body mass index (BMI) and enrollment on the renal transplant waiting list have not analyzed a national population of chronic dialysis patients.
Methods: 161,265 patients in the United States Renal Data System (USRDS) initiated on end-stage renal disease (ESRD) therapy between 1 April 1995 and 30 June 1997 who had data sufficient to calculate BMI were analyzed in an historical cohort study. Cox Regression analysis was used to model the association of BMI and rates of listing for renal transplantation, censored for death and receipt of renal transplant, and adjusted for demographics, comorbidities in the Medical Evidence Form (2728) and in comparison with patient survival.
Results: In univariate analysis, only patients with BMI <21.3 kg/m(2) had a statistically significant lower rate of listing compared to patients with BMI 24.5-28.6 kg/m(2) (6.1 vs. 7.5/100 person years). In Cox Regression analysis, patients with BMI <21.3 kg/m(2) had a 18% lower adjusted rate of listing and a 38% lower rate of survival, and patients with BMI >=24.5-28.7 had an 11% higher adjusted rate of listing and no significant difference in adjusted survival compared with patients with BMI>=28.7 kg/m(2). Caucasian females were disproportionately affected by high BMI.
Conclusions: Among ESRD patients, lower BMI was independently associated with reduced adjusted rates of listing. High BMI affected rates of listing disproportionately in caucasian females.