Readmission rates were found to be higher among persons who live in disadvantaged neighborhoods and who are discharged from hospitals serving a larger ratio of disadvantaged individuals, according to results from a study recently published in the Annals of Internal Medicine.
This observational study included 489,357 discharge cases from Maryland hospitals in 2015 that did not include newborns, mortality cases, or transfers to another acute care hospital. The area disadvantage index (the disadvantage of each individual’s neighborhood) and safety net index (each hospital’s mean discharged patient disadvantage) were considered as potential predictors for readmissions. Unplanned hospital readmission within 30 days constituted the primary outcome. The hospital readmission rate, or the number of readmissions per 100 discharges, was estimated using marginal modeling and generalized estimating equations, with adjustments for clinical readmission risk. The safety net index and the area disadvantage index were modeled as continuous variables because of the likelihood of a linear association between them.
Among the study’s discharge cases, 13.4% (n = 65,698) were 30-day readmissions. A readmission rate of 14.1% (95% CI, 13.6-14.5) was observed for individuals residing in 90th-percentile disadvantaged neighborhoods whereas the readmission rate was 12.5% (95% CI, 11.8-13.2) among persons in the 10th percentile. Similarly, a 14.8% (95% CI, 13.4-16.1) readmission rate was observed among individuals in the 90th percentile of the safety net index whereas the readmission rate was 11.6% (95% CI, 10.5-12.7) among comparable cases in the 10th percentile.
Maryland’s discharges had an overall area disadvantage index of 57 whereas the mean area disadvantage index was 50 for all Maryland residents. This signified overrepresentation of individuals from disadvantaged neighborhoods among discharges. The correlation between readmission risk and the hospital safety net index was 2-fold greater than the correlation between readmission risk and the neighborhood disadvantage status of the individual. Risk associated with moving between the 10th and 90th safety net index percentiles resulted in a 3.2-percentage-point difference in risk compared with a 1.6-percentage-point difference in risk associated with such a move in the area disadvantage index.
Limitations to this study include a focus on a single state and potential confounding because of lack of accounting for individual characteristics.
The study researchers concluded that “neighborhood disadvantage is associated with excess risk for readmission in two ways. One is the patient’s exposure to disadvantage in the neighborhood where they live and often recover after hospitalization. Individual patients bear this risk compared with patients from more advantaged neighborhoods treated in similar hospitals. The other, which is associated with roughly twice the variation in risk for readmission, is indirect, hospital-level exposure that can be measured by the mean disadvantage of a hospital’s discharged patients. This indirect exposure is largely independent of a patient’s direct exposure to neighborhood disadvantage and deserves further exploration.”
Jencks SF, Schuster A, Dougherty GB, Gerovich S, Brock JE, Kind AJH. Safety-net hospitals, neighborhood disadvantage, and readmissions under Maryland’s all-payer program: an observational study [published online July 2, 2019]. Ann Intern Med. doi:10.7326/M16-2671