Medicaid Expansion and 1-Year Mortality Among Young Adults Initiating Dialysis

Importance: The Affordable Care Act (ACA) provided continued Medicaid coverage to US children transitioning into young adulthood, but whether expansion averted deaths among younger adults with kidney failure remains unclear. Objective: To examine the association of Medicaid expansion with 1-year mortality among young adults with kidney failure initiating dialysis. Design, Setting, and Participants: This cohort study using a quasi-experimental difference-in-differences design compared changes in outcomes before and after Medicaid expansion between patients aged 19 to 23 years (affected by expansion) and patients aged 14 to 18 years (comparison group with unchanged eligibility). The study period extended from January 1, 2010, to December 31, 2019. Data analysis was performed from January 2023 to February 2025. Exposure: Medicaid expansion under the ACA. Main Outcomes and Measures: The primary outcome was 1-year mortality from the date of dialysis initiation. Secondary outcomes were Medicaid coverage, uninsurance, predialysis nephrology care, prescribed hemodialysis duration, modality of dialysis, and catheter use at hemodialysis initiation. Results: Among 7139 patients in expansion states, 2348 were 14 to 18 years old (1280 male [54.5%]; 1068 female [45.5%]), and 4791 were 19 to 23 years old (2717 male [56.7%]; 2074 female [43.3%]. One-year mortality for 19- to 23-year-olds declined from 3.6% (95% CI, 2.4% to 4.9%) in the pre-expansion period to 2.1% (95% CI, 1.2% to 3.0%) after expansion (change, -1.5 percentage points; 95% CI, -2.5 to -0.6), while for 14- to 18-year-olds, the concurrent mortality rate was 0.7% (95% CI, 0.3% to 1.0%) pre-expansion and 1.1% (95% CI, 0.5% to 1.7%) postexpansion (change, 0.4 percentage points; 95% CI, -0.3 to 1.1). The adjusted difference-in-difference estimate was -1.8 percentage points (95% CI, -2.9 to -0.7). Medicaid coverage for 19- to 23-year-olds increased from 37.1% to 48.5% and uninsurance rates declined from 19.4% to 7.8%. After accounting for concurrent changes among 14- to 18-year-olds, the adjusted difference-in-difference estimates were 8.4 percentage points (95% CI, 4.8 to 12.0) for Medicaid and -9.1 percentage points (95% CI, -12.4 to -5.8) for uninsurance. Medicaid expansion was associated with higher rates of predialysis nephrology care, prescribed hemodialysis sessions of 4 or more hours, and use of peritoneal dialysis, but not associated with use of catheters for hemodialysis or kidney transplant rates. Conclusions and Relevance: This study found that Medicaid expansion was associated with reductions in 1-year mortality among young adults with kidney failure initiating dialysis. Policy changes to health insurance programs may affect survival for young adults with this highly morbid condition.