Impact of Medicaid Expansion on Outcomes after Abdominal Aortic Aneurysm Repair.

OBJECTIVE: Lack of insurance has been independently associated with an increased risk of in-hospital mortality after abdominal aortic aneurysm repair, possibly due to worse control of comorbidities and delays in diagnosis and treatment. Medicaid expansion has improved insurance rates and access to care, potentially benefitting these patients. We sought to assess the association between Medicaid expansion and outcomes after abdominal aortic aneurysm repair.

METHODS: A retrospective analysis of Healthcare Cost and Utilization Project State Inpatient Databases data from 14 states between 2012-2018 was conducted. The sample was restricted to first-record abdominal aortic aneurysm repairs in adults under age 65 in states that expanded Medicaid on 1/1/2014 (Medicaid expansion group) or had not expanded before 12/31/2018 (non-expansion group). The Medicaid expansion and non-expansion groups were compared between pre-expansion (2012-2013) and post-expansion (2014-2018) time periods to assess baseline demographic and operative differences. We used difference-in-differences multivariable logistic regression adjusted for patient factors, open versus endovascular repair, and standard errors clustered by state. Our primary outcome was in-hospital mortality. Outcomes were stratified by insurance type.

RESULTS: We examined 8,995 patients undergoing abdominal aortic aneurysm repair, including 3,789 (42.1%) in non-expansion states and 5,206 (57.9%) in Medicaid expansion states. Rates of Medicaid insurance were unchanged in non-expansion states but increased in Medicaid expansion states post-expansion (non-expansion: 10.9% to 9.8%, p=0.346; expansion: 9.7% to 19.7%, p<0.001). One in ten patients from both non-expansion and Medicaid expansion states presented with ruptured aneurysms, which did not change over time. Rates of open repair decreased in both non-expansion and Medicaid expansion states over time (non-expansion: 25.1% to 19.2%, p<0.001; expansion: 25.2% to 18.4%, p<0.001). On adjusted difference-in-differences analysis between expansion and non-expansion states pre- to post-expansion, Medicaid expansion was associated with a 1.02% absolute reduction in in-hospital mortality among all patients (95% CI -1.87%, -0.17%; p=0.019). Additionally, among patients who were either on Medicaid or were uninsured - i.e., the patients most likely to be impacted by Medicaid expansion - a larger 4.17% decrease in in-hospital mortality was observed (95% CI -6.47%, -1.87%; p<0.001). In contrast, no significant difference-in-difference in mortality was observed for privately insured patients.

CONCLUSIONS: ME was associated with decreased in-hospital mortality after abdominal aortic aneurysm repair among all patients and particularly among patients who were either on Medicaid or were uninsured. Our results provide support for improved access to care for abdominal aortic aneurysm repair patients through Medicaid expansion.