Impact of Body Mass Index on Outcomes of Autogenous Fistulas for Hemodialysis Access.

Abstract Introduction The prevalence of obesity is increasing in the US. The treatment of end stage renal disease via hemodialysis spans the spectrum of body mass index (BMI). This study examines the impact of body mass index (BMI) on outcomes of autogenous fistulas for hemodialysis access in a large population based cohort of patients. Methods A retrospective study of all patients in the prospectively maintained United States Renal Database System who initiated hemodialysis between 2007-2014 was performed. Chi-square, T-tests, Kaplan-Meier, log-rank tests, multivariable logistic and Cox regression analyses were employed to evaluate access maturation, interventions, patency, and mortality. Results There were 300778 patients studied. Of these, 9394 (3.1%) were underweight, 87351 (29.1%) were normal weight, 86101 (28.6%) were overweight, 57047 (19%) were obese class I, 31077 (10.3%) were obese class II and 29808 (9.9%) were obese class III. There was no significant difference in maturation for patients who were underweight (adjusted hazard ratio (aHR): 0.97; 95%CI: 0.89-1.06, P=0.48), overweight (aHR: 1.01; 95%CI: 0.97-1.05, P=0.66), obese class I (aHR: 1.05; 95%CI: 0.99-1.09, P=0.22) or obese class II (aHR: 1.01; 95%CI: 0.94-1.05, P=0.98 relative to normal weight. However, there was a 6% decrease in maturation for obese class III patients (aHR: 0.94; 95%CI: 0.89-0.99, P=0.02) compared to normal weight patients. Primary (aHR: 0.93; 95%CI: 0.91-0.96, P Conclusions In this population-based cohort of hemodialysis dependent patients, obesity was associated with decrease in fistula maturation. Extremes of BMI were associated with lower patency, but higher BMI was associated with better patient survival. Obese patients nearing ESRD might require earlier referral for AVF placement in order to allow for maturation and AVF use at incident hemodialysis.