Temporal Risk Profile for Infectious and Noninfectious Complications of Hemodialysis Access

Vascular access complications are a major cause of morbidity in patients undergoing hemodialysis, and determining how the risks of different complications vary over the life of an access may benefit the design of prevention strategies. We used data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) to assess the temporal profiles of risks for infectious and noninfectious complications of fistulas, grafts, and tunneled catheters in incident hemodialysis patients. We used longitudinal data to model time from access placement or successful treatment of a previous complication to subsequent complication and considered multiple accesses per patient and repeated access complications using baseline and time-varying covariates to obtain adjusted estimates. Of the 7769 incident patients identified, 7140 received at least one permanent access. During a median follow-up of 14 months (interquartile range, 7–22 months), 10,452 noninfectious and 1131 infectious events (including 551 hospitalizations for sepsis) occurred in 112,085 patient-months. The hazards for both complication types declined over time in all access types: They were 5–10 times greater in the first 3–6 months than in later periods after access placement or a remedial access-related procedure. The hazards declined more quickly with fistulas than with grafts and catheters (P<0.001; Weibull regression). These data indicate that risks for noninfectious and infectious complications of the hemodialysis access decline over time with all access types and suggest that prevention strategies should target the first 6 months after access placement or a remedial access-related procedure.Clinical practice guidelines recommend the arteriovenous fistula as the optimal vascular access for hemodialysis because mature fistulas have lower rates of thrombosis and infection compared with synthetic arteriovenous grafts or central venous catheters.^1–3 Given the mortality, morbidity, and costs associated with the use of grafts and catheters and low rates of fistula use in the United States in the mid-1990s,⁴ national initiatives were created to increase the placement of fistulas.⁵ These programs have had markedly increased fistula prevalence since their inception.⁵ However, 20%–60% of patients treated with hemodialysis worldwide use grafts or catheters,^6,7 at least in part because their vessels are unsuitable for fistula creation.^8,9 Increasing fistula attempts in all patients may therefore be insufficient to improve access and patient outcomes. Considering the limited benefits of available pharmacologic interventions,^9–11 novel strategies are needed to improve access outcomes. A better understanding of the timing and risk of complications of each type of access would help to develop new therapies or approaches.^12,13There are limited data on the temporal profiles of risk for infectious and noninfectious complications in different forms of vascular access. The risk for noninfectious complications (e.g., stenosis and thrombosis) declines over the life of the access in both fistulas and grafts. Data from centers where local policies favor fistula creation, early transition from catheters to arteriovenous accesses, and limited use of grafts indicate that the hazard for access failure due to noninfectious complication is initially higher with fistulas than grafts, declines more quickly with fistulas, and is lower with fistulas than grafts within 3–6 months of access creation.¹⁴ This pattern is consistent with the known higher rates of primary failure in fistulas and inferior long-term outcomes in grafts,¹⁵ although results from this study need to be confirmed in larger cohorts and different populations. No other risk patterns have been described, including the temporal profiles of risks for noninfectious complications with permanent catheters. Furthermore, the risk profile for infectious complications in any access type, including access infection and sepsis, remains uncharacterized. Knowledge about how these risks vary over time may be important for informing studies seeking to test the effectiveness of new interventions and for designing strategies that can improve access-related outcomes.We sought to describe and compare the profile of the risks over time for infectious and noninfectious complications of each permanent access type (fistula, graft, and tunneled catheter), accounting for patient characteristics and considering multiple accesses per patient. To maximize the generalizability of the results, we used data from the Dialysis Outcomes and Practice Patterns Study (DOPPS), an ongoing large, international, prospective cohort study of dialysis practices and patient outcomes.