Mortality benefits of different hemodialysis access types are age dependent

Objective Risk of death in dialysis patients is lowest with arteriovenous fistulas (AVFs), followed by arteriovenous grafts (AVGs) and then intravenous hemodialysis catheters (HCs). Our aim was to analyze the effects of age at hemodialysis initiation on mortality across different access types. Methods All patients ≥18 years in the United States Renal Data System between the years 2006 and 2010 were analyzed. Spline modeling and risk-adjusted Cox proportional hazard models were used to analyze the effect of age on mortality for first dialysis access with AVF vs AVG vs HC. Results The study analyzed 507,791 patients (63.4 ± 0.02 years; 56.5% male; 40.9% mortality; follow-up, 1.57 ± 1.36 years). Increasing age was a significant predictor of overall mortality (adjusted hazard ratio [aHR], 1.03; P < .001). Compared with patients with HCs (n = 418,932), overall risk-adjusted mortality was lowest in patients with AVFs (n = 71,316; aHR, 0.63; P < .001) followed by AVGs (n = 17,543; aHR, 0.83; P < .001). AVF was superior to both HC and AVG for all age groups ( P < .001). However, there was a significant change in the relative efficacy of AVG at ages 48 years and 89 years based on spline modeling; there were no significant differences comparing adjusted mortality with AVG vs HC for patients aged 18 to 48 years or for patients >89 years, but AVG was superior to HC for patients 49 to 89 years of age (aHR, 0.811; P < .001). The mortality benefit of AVF was consistently superior to that of AVG and HC for patients of all ages (all, P < .001). Conclusions AVF is superior to AVG and HC regardless of the patient's age, including in octogenarians. In contrast, the mortality benefit of AVG over HC may not apply to younger (18-48 years) or older (>89 years) age groups. All patients 18 to 48 years should receive AVF for dialysis access whenever possible.