Hemodialysis Vascular Access and Risk of Major Bleeding, Thrombosis, and Cardiovascular Events: A Cohort Study.

Rationale & Objective: The risks of major bleeding, thrombosis, and cardiovascular events are elevated in patients receiving maintenance hemodialysis (HD). Our objective was to compare the risk of these outcomes in HD according to the permanent vascular access type. Study Design: Observational cohort study. Setting & Participants: Using data from the United States Renal Data System (2010-2015), we included patients with kidney failure who were greater than 18 years, had Medicare as the primary payer, were not using an oral anticoagulant, and were newly using an arteriovenous (AV) access for HD. Exposure: AV graft (AVG) or AV fistula (AVF). Outcomes: Major bleeding, venous thromboembolism, ischemic stroke, myocardial infarction, cardiovascular death, and critical limb ischemia. Analytical Approach: Comparing 17,763 AVG and 60,329 AVF users, we estimated the 3-year incidence rates and incidence rate ratios (IRRs) of each outcome using Poisson regression. IRRs were adjusted for sociodemographic and clinical covariates. Results: The use of an AVG, compared with that of an AVF, was associated with an increased risk of venous thromboembolism (10.8 vs 5.3 events per 100 person-years; adjusted IRR, 1.74; 95% CI, 1.63-1.85) but not with the risk of major bleeding (IRR, 1.04; 95% CI, 0.93-1.17). The use of an AVG was also potentially associated with a slightly increased risk of cardiovascular death (IRR, 1.09; 95% CI, 1.01-1.16). Limitations: This analysis focused on patients with a functioning AV access; adverse events that may occur during access maturation should also be considered when selecting a vascular access. Conclusions: The use of an AVG, relative to an AVF, in HD is associated with an increased risk of venous thromboembolism. Given recent guidelines emphasizing selection of the "right access" for the "right patient," the results of this study should potentially be considered as one additional factor when selecting the optimal access for HD.