Assessment of a policy to reduce placement of prosthetic hemodialysis access

Abstract

The aim of this study was to evaluate the determinants of access patency and revision, including the effects of reducing the placement of prosthetic hemodialysis access. A retrospective cohort study of all hemodialysis accesses placed at the Veteran's Administration Puget Sound Health Care System between 1992 and 1999 was conducted. A policy was instituted in 1996 that maximized the use of autogenous hemodialysis access. The impacts of the policy change, demographics, and comorbid factors on access type and patency, were examined. Primary and secondary patency rates were examined using the Kaplan--Meier method, and factors associated with failure and revision were examined using Cox proportional hazard models and Poisson regression. During the study, 104 accesses (61 prosthetic grafts and 43 autogenous fistulas) were placed prior to 1996, and 118 (31 prosthetic grafts and 87 autogenous fistulas) were placed after 1996. There was a significant increase in autogenous fistulas placed after 1996 (87 out of 118) compared with before 1996 (43 out of 104, P < 0.001). At one year, autogenous fistulas demonstrated superior primary patency (56 vs. 36%, P = 0.001) and secondary patency (72 vs. 58%, P = 0.003) compared with prosthetic grafts. After adjustment for age, race, side of access placement, and history of prior access placement, patients with a prosthetic graft were estimated to experience a 78% increase in the risk of primary access failure when compared with similar patients having an autogenous access [adjusted relative risk (aRR) = 1.78, 95% CI 1.21--2.62, P = 0.003)]. Similarly, the adjusted relative risk of secondary access failure for comparing prosthetic grafts with autogenous fistulas was estimated to be 2.21 (95% CI 1.38--3.54, P = 0.001). The adjusted risk of access revision was 2.89-fold higher for prosthetic grafts than for autogenous fistulas (95% CI 1.88--4.44, P < 0.001). Autogenous conduits demonstrated superior performance when compared with prosthetic grafts in terms of primary and secondary patency and number of revisions. A policy emphasizing the preferential placement of autogenous fistulas over prosthetic grafts may result in improved patency and a reduction in the number of procedures required to maintain dialysis access patency.