Assessing Between- and Within-Hospital Differences in Patient Safety Between Medicaid and Privately Insured Hospital Patients.

Objectives: The aims of the study are to investigate differences in rates of adverse safety events between nonelderly adult patients with Medicaid and those with private insurance and to assess whether differences are driven by differences in access to quality hospitals or differences in the quality of care delivered within hospitals.

Data source: Inpatient records from 26 states in 2017 were collected from the Agency for Health Care Research and Quality's Hospital Cost and Utilization Project.

Study design: This study measures differences in 11 patient safety indicators between patients with Medicaid coverage and patients with private insurance coverage. I use regression analysis to investigate differences in adverse safety events within hospitals. I further establish hospital-level quality based on overall rates of adverse safety events and use regression analysis to evaluate the difference in the probability of admission to high-quality hospitals.

Data collection/extraction: This study uses hospital discharge data that is restricted to adults ages 19-64 with Medicaid or private coverage.

Principal findings: Relative to privately insured patients, Medicaid patients had significantly higher rates of adverse safety events on 8 of 11 patient safety indicators, including on 6 of 7 surgery-related patient safety indicators. Medicaid patients experience respiratory failure and sepsis infections at rates that are 2.9 and 2.5 cases per 1000 greater than rates experienced by privately insured patients. After adjusting for demographic characteristics, patient diagnostic classifications and comorbidities, and geographic factors, 6 of 11 differences in patient safety indicators remained large and statistically significant. These differences were unchanged when further including hospital indicators, indicating that Medicaid and privately insured patients receive different quality of care within hospitals. There is little association between overall hospital quality and differences in the probability of admission between Medicaid and privately covered patients.

Conclusions: Medicaid patients received lower quality of care, based on patient safety metrics, relative to privately insured patients within the same hospitals. Reducing payer disparities in adverse safety events requires reforming staffing and treatment patterns for Medicaid and privately insured patients within hospitals.

Study date and location: Analysis for this study was conducted in 2023 at the Urban Institute and at Loyola University Chicago.