Background: Synthetic grafts have generally been found to exhibit lower survival rates and higher complication rates than native arteriovenous fistulae. We investigated whether survival of grafts relative to fistulae was better in facilities with a preference for grafts, hypothesizing that such facilities may place more grafts because grafts produced superior outcomes.
Methods: The study was based on a national U.S. sample of 133 hemodialysis facilities participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective, observational study of dialysis treatment practices and outcomes. Vascular access preferences were ascertained from medical directors, nurse managers, and actual practice within each facility (% graft use among prevalent patients). Logistic regression was used to model the odds ratio (OR) of graft placement (vs. fistula) and Cox regression was used to model time from access creation to initial failure.
Results: Grafts were preferred by 21% of medical directors and 40% of nurse managers. Patients in facilities in which the medical director or nurse manager expressed a preference for grafts were more than twice as likely to have a graft than a fistula (AOR = 2.3, P < 0.01; reference group = facilities that did not prefer grafts), suggesting that facility preferences influence the type of access created. Overall, grafts were more prevalent than fistulae in dialysis facilities, but displayed a higher relative risk of failure (RR 1.33, P < 0.0001). However, the risk of graft versus fistula failure did not vary by expressed preference of the medical director: the relative risk of graft versus fistula failure was 1.39 in facilities in which the medical director preferred grafts and 1.39 in facilities in which the medical director preferred fistulae. Moreover, the relative risk of graft versus fistula failure was 1.57 in facilities that used more than the median percentage of grafts and 1.19 in facilities that used less than the median percentage of grafts.
Conclusions: No evidence was found that graft outcomes are superior in facilities that prefer grafts to fistulae. The observed variation in vascular access practice patterns suggests opportunities for quality improvement if optimal practices can be defined.