Associations between hemodialysis access type and clinical outcomes: a systematic review

Abstract

Clinical practice guidelines recommend an arteriovenous fistula as the preferred vascular access for hemodialysis, but quantitative associations between vascular access type and various clinical outcomes remain controversial. We performed a systematic review of cohort studies to evaluate the associations between type of vascular access (arteriovenous fistula, arteriovenous graft, and central venous catheter) and risk for death, infection, and major cardiovascular events. We searched MEDLINE, EMBASE, and article reference lists and extracted data describing study design, participants, vascular access type, clinical outcomes, and risk for bias. We identified 3965 citations, of which 67 (62 cohort studies comprising 586,337 participants) met our inclusion criteria. In a random effects meta-analysis, compared with persons with fistulas, those individuals using catheters had higher risks for all-cause mortality (risk ratio=1.53, 95% CI=1.41-1.67), fatal infections (2.12, 1.79-2.52), and cardiovascular events (1.38, 1.24-1.54). Similarly, compared with persons with grafts, those individuals using catheters had higher risks for mortality (1.38, 1.25-1.52), fatal infections (1.49, 1.15-1.93), and cardiovascular events (1.26, 1.11-1.43). Compared with persons with fistulas, those individuals with grafts had increased all-cause mortality (1.18, 1.09-1.27) and fatal infection (1.36, 1.17-1.58), but we did not detect a difference in the risk for cardiovascular events (1.07, 0.95-1.21). The risk for bias, especially selection bias, was high. In conclusion, persons using catheters for hemodialysis seem to have the highest risks for death, infections, and cardiovascular events compared with other vascular access types, and patients with usable fistulas have the lowest risk.

Figure 1.

Flow diagram of the identification process for eligible studies. Hospitalizations were from any cause.

Figure 2.

Risk of bias in the included articles. Two items were considered for each quality domain to define the risk of bias of the included articles (n=67) as described in Supplemental Table 4; numbers indicate the numbers of articles.

Figure 3.

Primary outcome: risk of all-cause mortality for the use of central venous catheters versus fistulas or grafts and the use of arteriovenous grafts versus fistulas in people on hemodialysis; studies are ordered by weight. We pooled the estimates reported by Polkinghorne et al. for the comparison of catheters versus fistulas (three estimates) and catheters versus grafts (three estimates) according to the time spent on hemodialysis when patients were registered; we also pooled the estimates reported by Foley et al. for the comparison of catheters versus fistulas and catheters versus grafts (each with three estimates) according to whether the patient has a catheter only, a catheter with a maturing fistula, or a graft.