Association of Medicaid expansion with access to thyroidectomy for benign disease at high-volume centers

Background: Insurance-based disparities in access to thyroidectomy are well established. Patients undergoing thyroidectomy by high-volume surgeons have fewer complications and better postoperative outcomes. The aim of this study was to evaluate the association of Medicaid expansion with access to high-volume centers for thyroidectomy for benign disease. Methods: The Vizient Clinical Data Base was queried for adult operations for benign thyroid disease from 2010 to 2019. Centers were sorted by volume into quartiles. Difference-in-difference analysis evaluated changes in insurance populations in expansion and non-expansion states after Medicaid expansion. Odds of patients undergoing operations in the 4 volume quartiles after stratifying by insurance and Medicaid expansion status were calculated. Results: A total of 82,602 patients underwent operations at 364 centers. Expansion states increased Medicaid coverage in all volume quartiles compared to non-expansion states after Medicaid expansion (Q1, +4.87%, Q2, +5.35%, Q3, +8.57%, Q4, +4.62%, P < .002 for all). After Medicaid expansion, Medicaid patients had higher odds of undergoing operation at lower volume hospitals compared to the highest volume centers in both expansion states (Q1, ref, Q2, 1.82, Q3, 1.76, Q4, 1.67, P < .001) and non-expansion states (Q1, ref, Q2, 1.54, Q3, 2.04, Q4, 1.44, P < .001). Privately insured patients were most likely to undergo their operation at the highest volume centers in all states (E: Q1, ref, Q2, 0.78, Q3, 0.74, Q4, 0.66, P < .001; NE: Q1, ref, Q2, 0.89, Q3, 0.58, Q4, 0.85, P < .001). Conclusion: Medicaid expansion increased Medicaid coverage in expansion states, but Medicaid patients in both expansion and non-expansion states were less likely to be operated on at the highest volume centers compared to privately insured patients. Persistent barriers to accessing high-volume care still exists for Medicaid patients.