Clinical significance of maturing vascular access for incident hemodialysis patients

Background: Reliable vascular access is required for hemodialysis (HD). Central venous catheters (CVC) can be used immediately, but are traditionally associated with increased mortality compared to arteriovenous fistulas or grafts (AVF/AVG). Immature fistulas or grafts may or may not become usable; their impact on long-term mortality or transplant has not been defined. Methods: Adult incident HD patients entering the United States Renal Data System between 1/2018 and 12/2019 were identified, and included if still on HD at day 90. Initial dialysis accesses were categorized as mature AVF/AVG, CVC-only, or CVC with an fistula or graft that was not ready for use (CVC-plus). Cox models were used to examine the associations between access type and patient mortality, and logistic models for kidney transplant waitlist appearance, using propensity-matched samples. CVC-plus was the reference group for all models. Results: Among 214,673 patients, 66% had CVC-only, 15% CVC-plus, and 19% AVF/AVG. Over median follow up of 30 months, 45% died and 5% received kidney transplants. Compared to patients with CVC-plus, having CVC-only was associated with increased death (HR = 1.31, 95% CI = 1.29–1.35, p < 0.001) but similar rates of kidney transplantation (HR = 1.01, 95% CI = 0.97–1.14, p = 0.20), despite more waitlisting. Having AVF/AVG was associated with decreased death (HR = 0.81, 95% CI = 0.79–0.83) and increased transplantation (HR = 1.39, 95% CI = 1.30–1.50), p < 0.001 for both. Conclusions: Initiating HD with CVC-plus was advantageous compared to CVC-only, but outcomes were inferior to those of patients initiating HD with mature AVF/AVG.