Safety-Net Hospitals, Neighborhood Disadvantage, and Readmissions Under Maryland's All-Payer Program: An Observational Study

Abstract

Background: Safety-net hospitals have higher-than-expected readmission rates. The relative roles of the mean disadvantage of neighborhoods the hospitals serve and the disadvantage of individual patients in predicting a patient's readmission are unclear.

Objective: To examine the independent contributions of the patient's neighborhood and the hospital's service area to risk for 30-day readmission.

Design: Retrospective observational study.

Setting: Maryland.

Participants: All Maryland residents discharged from a Maryland hospital in 2015.

Measurements: Predictors included the disadvantage of neighborhoods for each Maryland resident (area disadvantage index) and the mean disadvantage of each hospital's discharged patients (safety-net index). The primary outcome was unplanned 30-day hospital readmission. Generalized estimating equations and marginal modeling were used to estimate readmission rates. Results were adjusted for clinical readmission risk.

Results: 13.4% of discharged patients were readmitted within 30 days. Patients living in neighborhoods at the 90th percentile of disadvantage had a readmission rate of 14.1% (95% CI, 13.6% to 14.5%) compared with 12.5% (CI, 11.8% to 13.2%) for similar patients living in neighborhoods at the 10th percentile. Patients discharged from hospitals at the 90th percentile of safety-net status had a readmission rate of 14.8% (CI, 13.4% to 16.1%) compared with 11.6% (CI, 10.5% to 12.7%) for similar patients discharged from hospitals at the 10th percentile of safety-net status. The association of readmission risk with the hospital's safety-net index was approximately twice the observed association with the patient's neighborhood disadvantage status.

Limitations: Generalizability outside Maryland is unknown. Confounding may be present.

Conclusion: In Maryland, residing in a disadvantaged neighborhood and being discharged from a hospital serving a large proportion of disadvantaged neighborhoods are independently associated with increased risk for readmission.

Primary funding source: National Institute on Minority Health and Health Disparities and Maryland Health Services Cost Review Commission.

Figure 1.

Variation in ADI in Maryland. Data are from 2010–2013, the most recent data set available when the analysis was performed (13). ADI = area disadvantage index.

Figure 2.

Relationship between hospital safety-net index and adjusted readmission rate. Hospital safety-net index is the mean ADI for a hospital’s discharges. Readmission rates were indirectly adjusted for case mix to the statewide average. Points are scaled to reflect discharge volume, which ranged from 263 to 36 060. Correlation = 0.7. ADI = area disadvantage index.