The effect of Medicaid expansion on survival outcomes among individuals with chronic myeloid leukemia

Abstract Background: Chronic Myeloid Leukemia (CML) is a rare hematologic malignancy primarily affecting older adults, with a median age at diagnosis of approximately 64 years. While the introduction of tyrosine kinase inhibitors has dramatically improved CML survival rates, disparities persist based on access to timely diagnosis and treatment. Insurance coverage, particularly for low-income individuals, plays a critical role in ensuring equitable access to care. The Affordable Care Act's (ACA) Medicaid expansion provision was designed to improve healthcare access for low-income adults, yet its impact on overall survival among individuals with CML remains underexplored. This study aims to evaluate the association between Medicaid expansion under the ACA and overall mortality among adults aged 40–64 diagnosed with CML in the United States (US). Methods: We conducted a retrospective cohort study using data from the National Cancer Database (NCDB) spanning 2005 to 2022. States in the US were categorized as either early Medicaid expansion or non-expansion states based on ACA policy adoption. The study period was divided into a pre-expansion era (2005–2013) and a post-expansion era (2014–2022). To evaluate the association between Medicaid expansion and all-cause mortality among individuals diagnosed with CML, we employed a Difference-in-Differences (DiD) analytic approach using Cox proportional hazards regression. Models were adjusted for a comprehensive set of demographic, clinical, tumor-specific, and neighborhood-level socioeconomic covariates. Results: Among 13,440 individuals with CML, 5,589 (41.6%) were diagnosed before and 7,851 (58.4%) after Medicaid expansion in 2014. Expansion states saw Medicaid coverage rise from 13.1% to 21.3% (p < 0.001), while non-expansion states decreased from 11.3% to 10.8% (p < 0.001). The uninsured rate dropped from 8.7% to 3.7% (p < 0.001) in expansion states, as well as from 15.3% to 11.7% (p < 0.001) in non-expansion states. Medicaid expansion was associated with a 78.8% reduction in overall mortality compared to non-expansion states (DiD: -78.8%; 95% CI, -140.0% to -17.5%; p < 0.001). Reductions were consistent across racial and ethnic groups. Conclusion: Medicaid expansion under the ACA was associated with substantial increases in insurance coverage and a significant reduction in overall mortality among individuals with CML. Mortality improvements were consistent across racial and ethnic groups, highlighting the policy's potential to reduce disparities and improve cancer outcomes at a population level. These findings underscore the crucial role of health insurance access in promoting equity in cancer survival.