Maturing arteriovenous accesses in incident haemodialysis patients and first-year outcomes

Abstract

Introduction: Nephrologists have increased arteriovenous access placement in patients with chronic kidney disease. Not yet usable ‘maturing’ arteriovenous fistulas and grafts are nearly as common as mature arteriovenous fistulas or grafts. Little has been reported about patients initiating haemodialysis with unready arteriovenous fistulas or grafts. Methods: The United States Renal Data System records for all adult patients initiating haemodialysis with central venous catheters between July 2010 and December 2011. Patients were categorized by whether a maturing arteriovenous fistula or graft was present. Transition to working arteriovenous fistula or graft was determined from linked Medicare claims. Modality changes and survival were ascertained. A logistic model for one-year survival and a subdistribution hazards model for transition to working arteriovenous fistula or graft, accounting for the competing risk of death, were constructed. Results: Compared to central venous catheter-only, maturing arteriovenous fistula or graft was associated with access conversion (hazard ratio = 2.23 (2.17–2.30) and 3.25 (2.97–3.56), respectively, p < 0.001 for both). Median time to conversion, among those who transitioned, was 95 days (interquartile range = 56–139) for patients with a maturing arteriovenous graft and 135 days (98–198) with a maturing arteriovenous fistula, versus 193 days (138–256) with central venous catheter-only. Pre-dialysis nephrology care, male sex and non-Caucasian race were associated with access conversion. Patients without a maturing arteriovenous fistula or graft had decreased odds of one-year survival (odds ratio = 0.61 (0.58–0.66), p < 0.001), which attenuated with adjustment for access conversion (adjusted odds ratio = 1.06 (0.98–1.13), p = 0.2). Conclusion: Maturing arteriovenous fistulas or grafts were associated with enhanced first-year survival and increased opportunity for working arteriovenous fistulas or grafts, which may reflect pre-dialysis decision-making, quality of care and comorbid diseases. Central venous catheter exposure was substantial, even among patients with maturing access. Contributory factors prolonging conversion to arteriovenous access need to be identified and addressed.