The effect of pre-Affordable Care Act (ACA) Medicaid eligibility expansion in New York State on access to specialty surgical care

Abstract

Background: Critics argue that expanding health insurance coverage through Medicaid may not result in improved access to care. The Affordable Care Act provides reimbursement incentives aimed at improving access to primary care services for new Medicaid beneficiaries; however, there are no such incentives for specialty services. Using the natural experiment of Medicaid expansion in New York (NY) State in October 2001, we examined whether Medicaid expansion increased access to common musculoskeletal procedures for Medicaid beneficiaries.

Methods: From the State Inpatient Database for NY State, we identified 19- to 64-year-old patients who underwent lower extremity large joint replacement, spine procedures, and upper/lower extremity fracture/dislocation repair from January 1998 to December 2006. We used interrupted time series analysis to evaluate the association between Medicaid expansion and trends in the relative and absolute number of Medicaid beneficiaries who underwent these musculoskeletal procedures.

Results: Before Medicaid expansion, we observed a slight but steady temporal decline in the proportion of musculoskeletal surgical patients who were Medicaid beneficiaries. After expansion, this trend reversed, and by 5 years after Medicaid expansion, the proportion of musculoskeletal surgical patients who were Medicaid beneficiaries was 4.7 percentage points [95% confidence interval, 3.9-5.5] higher than expected, based on the preexpansion time trend.

Conclusion: Medicaid expansion in NY State significantly improved access to common musculoskeletal procedures for Medicaid beneficiaries.

Figure 1. Quarterly probability of Medicaid beneficiaries and Uninsured patients receiving the selected musculoskeletal procedures

Red/blue square plots: Observed proportion of Medicaid/Uninsured patients respectively, with the intervention. Red/blue “x” plots: Expected proportion of Medicaid/Uninsured patients respectively if the intervention had not occurred. Dashed line: Time of intervention. At quarter 35 (roughly 5 years after the intervention), there were approximately 5% (red double arrow) more Medicaid patients treated than would have been if the intervention had not occurred. At the same time, there were approximately 2% less uninsured patients than would have been without the intervention (blue double arrow).

Figure 2. Quarterly population-adjusted number of Medicaid beneficiaries and Uninsured patients who received musculoskeletal procedures

Red/blue square plots: Observed population-adjusted number of Medicaid/Uninsured patients respectively, with the intervention. Red/blue “x” plots: Expected population-adjusted number of Medicaid/Uninsured patients respectively if the intervention had not occurred. Dashed line: Time of intervention. At quarter 35 (roughly 5 years after the intervention), approximately 5/100,000 (red square) patients treated were Medicaid beneficiaries compared to 2.8/100,000 (red “x”) if the intervention had not occurred. Additionally, the number of uninsured patients at quarter 0 and 35 were 1.4/100,000 and 1.5/100,000 respectively with little variation in the quarters in between.