Contribution of psychiatric illness and substance abuse to 30-day readmission risk

BACKGROUND Little is known about the contribution of psychiatric illness to medical 30‐day readmission risk. OBJECTIVE To determine the independent contribution of psychiatric illness and substance abuse to all‐cause and potentially avoidable 30‐day readmissions in medical patients. DESIGN Retrospective cohort study. SETTING Patients discharged from the medicine services at a large teaching hospital from July 1, 2009 to June 30, 2010. MEASUREMENTS The main outcome of interest was 30‐day all‐cause and potentially avoidable readmissions; the latter determined by a validated algorithm (SQLape) in both bivariate and multivariate analysis. Readmissions were captured at 3 hospitals where the majority of these patients are readmitted. RESULTS Of 6987 discharged patients, 1260 were readmitted within 30 days (18.0%); 388 readmissions were potentially avoidable (5.6%). In multivariate analysis, 2 or more prescribed outpatient psychiatric medications (odds ratio [OR]: 1.1, 95% confidence interval [CI]: 1.01‐1.20) or any prescription of anxiolytics (OR: 1.16, 95% CI: 1.00–1.35) were associated with increased all‐cause readmissions, whereas discharge diagnoses of anxiety (OR: 0.82, 95% CI: 0.68‐0.99) or substance abuse (OR: 0.80, 96% CI: 0.65‐0.99) were associated with fewer all‐cause readmissions. These findings were not replicated as predictors of potentially avoidable readmissions; rather, patients with discharge diagnoses of depression (OR: 1.49, 95% CI: 1.09‐2.04) and schizophrenia (OR: 2.63, 95% CI: 1.13‐6.13) were at highest risk. CONCLUSIONS Our data suggest that patients treated during a hospitalization for depression and for schizophrenia are at higher risk for potentially avoidable 30‐day readmissions, whereas those prescribed more psychiatric medications as outpatients are at increased risk for all‐cause readmissions. These populations may represent fruitful targets for interventions to reduce readmission risk. Journal of Hospital Medicine 2013;8:450–455. © 2013 Society of Hospital Medicine