Association Between Vascular Access Type in Hemodialysis Patients and Subsequent Kidney Transplant Outcomes

Background: Type of vascular access for hemodialysis (arteriovenous fistula vs. arteriovenous graft vs. central venous catheter) is strongly associated with outcomes in patients with end-stage kidney disease undergoing hemodialysis. Whether a similar association exists with outcomes after kidney transplant is unknown. Objectives: To test for an association among types of vascular access used for hemodialysis and outcomes after kidney transplant. Study Design: Retrospective cohort study of hemodialysis patients receiving a first kidney transplant. Setting and Participants: Merged data from the US Renal Data System and the electronic health records of a large dialysis organization (2006–2011). Only patients receiving a kidney transplant after undergoing \u3e30 days of hemodialysis were included. Intervention: Hemodialysis access used during the most recent outpatient hemodialysis session prior to kidney transplant. Outcomes: Patients were followed from kidney transplant for all-cause mortality, kidney allograft loss from any cause, and allograft loss not from death. Measurements: Hazard ratio, HR, and 95% confidence intervals. Results: Among 9291 patients who underwent kidney transplantation between 2006–2011, 65.3% had an arteriovenous fistula and 20.4% had an arteriovenous graft as the primary vascular access type and 14.3% had central venous catheter. Cox proportional hazards regression models adjusted for demographic variables, comorbidities, transplant characteristics, and laboratory parameters found no associations between vascular access type and all-cause mortality (HR=1.13; 95% CI, 0.97-1.33 for arteriovenous graft; HR=1.00; 95% CI, 0.83-1.21 for central venous catheter). Similarly, arteriovenous graft and central venous catheter use were not independently associated with all-cause allograft loss compared with arteriovenous fistula use (HR=1.13; 95% CI, 1.00-1.28 for arteriovenous graft; HR=1.12, 95% CI, 0.96-1.29 for central venous catheter). Central venous catheter use was associated with a 30% higher risk of allograft loss from causes other than death compared to use of an arteriovenous fistula (HR=1.30; 95% CI, 1.06-1.57,). No such association was found for use of arteriovenous grafts (HR: 1.17; 95% CI, 0.98-1.39). Limitations: The study is based on retrospective data analysis and is susceptible to information bias and ascertainment bias related to the nature of data collection. Residual confounding could be present as well due to unmeasured confounders and imperfect variable ascertainment. Conclusions: End-stage renal disease is a public health concern that continues to increase in prevalence accompanied by a growing economic burden. Hemodialysis is the most common form of kidney replacement therapy offered to these patients prior to undergoing kidney transplant. This study identified potential associations of central venous catheter use with allograft loss from all causes other than death when compared to the arteriovenous fistulas. No association was present with the use of arteriovenous graft prior to the transplant with all–cause mortality, allograft loss from all causes as well as allograft loss from all causes other than death, compared to the arteriovenous fistula use. For the clinician, the present study does not provide convincing support for the hypothesis that type of vascular access pre-transplant is a strong determinant of post-transplant outcomes