The association of Medicaid expansion and parathyroidectomy for benign disease: Insurance status remains an important factor in access to high-volume centers

Background: Medicaid expansion has been associated with improved access to surgical care at high-volume centers. Its impact on parathyroidectomy, however, is unclear. We evaluated the association between Medicaid expansion and parathyroidectomy at high- and low-volume centers.

Methods: The Vizient Clinical Data Base was queried for parathyroidectomies. Patients were grouped by insurance status and pre- and post-Medicaid expansion periods. Hospitals were stratified into tertiles (T1-T3) by operative volume (T1 = highest-volume centers). Odds of parathyroidectomy and a difference-in-differences analysis were conducted.

Results: In total, 31,983 patients were identified. Patients were predominantly privately insured (49.9%). Uninsured and Medicaid patients had increasing odds of operation at lower-tertile centers (odds ratio: T1 = ref; uninsured: T2 = 10.0, T3 = 15.8; Medicaid: T2 = 6.2, T3 = 13.5; P < .001). Medicare patients, however, were less likely to undergo operation at lower-volume centers (odds ratio: T2 = 0.89, P < .001; T3 = 0.92, P = .002). Privately insured patients were the least likely to receive care at low-volume centers (odds ratio: T3 = 0.7, P < .001). Medicaid patients in nonexpansion states had 12-16 times higher odds of parathyroidectomy at lower-volume hospitals than their counterparts in expansion states (expansion/nonexpansion states: pre-expansion T3 = 2.3/28.0; postexpansion T3 = 1.3/21.4). Expansion was associated with an increase in the proportion of parathyroidectomy for Medicaid patients, with larger gains seen at higher-volume centers (T1 = 5.0%, P = .01; T2 = 3.1%, P = .001; T3 = 2.7%, P = .03). Expansion was not associated with changes in payor distribution for uninsured, Medicare, or privately insured patients.

Conclusions: Medicaid expansion was associated with an increase in parathyroidectomy for Medicaid patients at high-volume centers. However, in nonexpansion states, access to surgical treatment at high-volume centers remains limited for uninsured and underinsured patients.