Prospective Analysis of Arteriovenous Fistula Performance in the Context of Competing Risks.

Abstract

Background: Many patients with newly created arteriovenous fistulas (AVF) may die before the AVF is needed for hemodialysis. However, formal competing risks frameworks are rarely used to report AVF patency, which may lead to biased estimates. We sought to identify the proportion of newly created AVF experiencing primary non-function and to describe long-term patency using a competing risk framework.

Methods: We did a prospective observational study in 257 adults with newly created AVF in Alberta, Canada. The primary outcome was primary non-function. Secondary outcomes included loss of primary-patency, loss of assisted primary-patency, and loss of secondary functional-patency. Results were presented using icon-array plots to form the basis for future decision aids.

Results: Participants were 63.0% male with mean age 62.3 years and median follow-up of 18.5 months (range 0.02-180 months). Of 257 participants, 50 could not be assessed for function or primary non-function, usually due to death. Of the remaining 207, 102 (49.3%) had primary non-function, and function was ultimately established for 142 (68.6%). Thus, only 142 of the 257 participants (55.3%) ultimately used the AVF for hemodialysis. High rates of competing risks led to biased results from Kaplan-Meier analyses of lost patency. When accounting for competing risks, loss of primary-patency among AVF with established function was 36.6%, 65.5% and 66.2%, at 1y, 3y and 5y respectively.

Conclusions: Only 55% of fistulas were ultimately used for hemodialysis when accounting for competing risks and primary non-function. These results and the icon-array plots may inform discussions surrounding vascular access options for patients.