Date of Award

January 2025

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Robert B. Schonberger

Abstract

ASSOCIATION OF MEDICARE ELIGIBILITY ON SURGICAL CARE ACCESS, A REGRESSION DISCONTINUITY DESIGN

Amanda Jankelovits, Julian Zhao, Hugo He, Hung-Mo Lin, Robert B. Schonberger, Department of Anesthesiology, Yale University, School of Medicine, New Haven, CT

The widespread onset of Medicare eligibility at age 65 has expanded access to healthcare, particularly among those previously uninsured. However, disparities in healthcare coverage still exist, especially for underrepresented minorities and low-income individuals. In this analysis, we utilize a regression discontinuity design to understand the effects of new onset Medicare eligibility at age 65 on access to surgical care at a large non-profit health system, focusing on disparities related to race and insurance type.

We conducted a single center, retrospective analysis of 20,508 surgical case data from patients aged 55 to 75, spanning 2018 to 2023, using data extracted from our local Multicenter Perioperative Outcomes Group (MPOG) registry. We studied surgical volume data of ten surgical procedures, classified as five non-emergent, or “deferrable” (cataract removal, colonoscopy, uncomplicated hernia repair, bariatric surgery, and carpal tunnel release) and five urgent, or “non-deferrable” (femur fracture repair, long bone fracture repair of the tibia and/or fibula, appendectomy, neurosurgical burr hole intervention, and neurovascular intervention). Univariate and multivariate analyses were performed to assess the impact of Medicare eligibility on surgical access. The local MPOG registry was approved by the Yale School of Medicine IRB with waiver of consent.

Within the cohort of surgical patients, minority individuals had significantly higher odds of undergoing deferrable surgeries as opposed to non-deferrable surgeries compared to non-Hispanic Whites both before (OR: 1.98, CI: 1.59-2.46, p < 0.001) and after age 65 (OR: 1.87, CI: 1.07-3.29, p <0.05).

For patients with private insurance, the odds of deferrable surgeries (as opposed to non-deferrable surgeries) for age 65 and older appeared higher than that of the under 65 group but failed to reach statistical significance (OR: 1.20, CI: 0.80-1.80). For patients with public insurance, age had no significant impact on the odds of undergoing deferrable surgeries (OR: 0.99, CI: 0.41-2.37).

When comparing insurance types, patients under 65 with public insurance had significantly lower odds of undergoing deferrable surgeries, as opposed to non-deferrable surgeries, relative to those with private insurance (OR: 0.76, CI: 0.59-0.9, p = 0.031). For individuals aged 65 and older, public insurance was still associated with lower odds of undergoing deferrable surgeries compared to private insurance, though this difference was no longer significant (OR: 0.62, CI: 0.30-1.29).

The distribution of surgeries varied by insurance type and age. The shift in payer types from private to public was more pronounced for deferrable procedures compared to non-deferrable at age 65. Trends in bariatric surgery showed a slight decrease before age 65, followed by an increase post Medicare eligibility at age 65, potentially reflecting delayed access to these procedures until Medicare coverage began.

This study underscores persistent disparities in surgical access. Among patients under 65, those with public insurance had significantly lower odds of undergoing deferrable surgeries (as opposed to non-deferrable surgeries) compared to those with private insurance. This effect was no longer significant for individuals 65 and older. Interestingly, minority patients demonstrated higher odds of undergoing deferrable surgeries, as opposed to non-deferrable surgeries, compared to non-Hispanic White patients, both before and after age 65. This trend may reflect a higher prevalence of chronic health conditions, as well as delayed access to preventative care, both of which disproportionately affect underrepresented populations, ultimately leading to a greater need for surgical intervention.

Study limitations include Connecticut’s early adoption of Medicaid expansion, which may diminish the observed impact of Medicare eligibility, as well as the inclusion of procedures inherently influenced by age and delays in care. Future analyses will further explore and address these disparities.

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