Predialysis Nephrology Care Disparities and Incident Vascular Access Among Hispanic Individuals.

Importance: Predialysis nephrology care is associated with the likelihood of having a mature, usable arteriovenous access for starting hemodialysis (ie, incident vascular access), a key care quality metric for patients with kidney failure. However, the magnitude of this association has not been quantified to date. Objective: To quantify the attributable association between lack of access to predialysis nephrology care and incident vascular access outcomes among Hispanic patients. Design, Setting, and Participants: This cohort study is a retrospective analysis of the 2021 US Renal Database System. Participants were all adult Medicare recipients initiating hemodialysis between 2010 and 2019; primary analysis was restricted to those with at least 6 months of predialysis Medicare status. Data analysis was performed from June 2022 to November 2024. Exposure: Self-reported race and ethnicity, with the non-Hispanic White category serving as the reference and Hispanic ethnicity as the primary comparator. Any predialysis nephrology care was the primary mediator, and at least 6 months of nephrology care and predialysis kidney disease education were the mediators for sensitivity analyses. Main Outcomes and Measures: The attributable association between predialysis nephrology care and incident vascular access (ie, the composite of arteriovenous fistula [AVF] or arteriovenous graft [AVG]) disparity was the primary outcome, and its attributable association between remaining incident access types, including central venous catheter (CVC) with maturing in-situ AVF or AVG, and CVC without any other access (CVC only) disparity, were the secondary outcomes. Causal mediation analysis with logistic regression was used to determine the unadjusted and adjusted associations. Results: Among 427 340 eligible patients undergoing incident hemodialysis (mean [SD] age, 72.65 [10.68] years; 241 420 male [56.5%]), 92 887 (21.7%) were Black, 46 146 (10.8%) were Hispanic, 269 697 (63.1%) were White, and 18 610 (4.35%) were other races and ethnicities. AVF was used in 62 075 patients (14.5%), AVG in 13 163 patients (3.1%), and CVC in 351 315 patients (82.2%). Compared with White patients, Hispanic patients had adjusted odds ratios (aORs) of 0.70 (95% CI, 0.68-0.72) for receiving predialysis nephrology care and 0.77 (95% CI, 0.75-0.80) for receiving incident vascular access, for a 23% lower rate. A lack of nephrology care accounted for 32.59% of incident vascular access and 62.00% of maturing vascular access underuse. Sensitivity analyses enhancing the predialysis care disparities strengthened incident vascular access disparity and the attributable association. Secondary analyses revealed that compared with White patients, Hispanic individuals with CVC and a maturing AVF or AVG had 38% (aOR, 1.38; 95% CI, 1.23-1.53) higher odds and those with CVC only had 30% (aOR, 1.30; 95% CI, 1.25-1.35) higher odds of conversion to a functional AVF or AVG within the first year of dialysis, with predialysis care negatively mediating these outcomes. Conclusions and Relevance: This retrospective cohort study of incident hemodialysis patients found that system-based disparities in predialysis access to nephrology care contribute to approximately one-third of incident vascular access disparities among Hispanic individuals. Targeted system-based remedies and policies are needed to improve timely identification and nephrology referrals among Hispanic individuals, for equitable improvements in incident kidney failure outcomes.