Hospitalization outcomes of people who use drugs: One size does not fit all.

People with opioid use disorder (OUD) have worse hospital outcomes and higher healthcare costs. There are rising reports of people with OUD also using other classes of drugs, however patterns of substance use have not been evaluated for differential effects on hospital outcomes. We performed a data-analysis of the Healthcare Utilization Project's National Readmissions Database, examining the effects of patterns of substance use, age, gender, and diagnosis on the outcomes of Against Medical Advice (AMA) discharges and 30-day readmissions. About one-third of the patients with OUD who were admitted to the hospital had at least one additional substance use disorder (SUD). Thirteen percent of persons with OUD were discharged AMA, and 12% were readmitted to the hospital within 30 days of discharge. Compared to people with OUD alone, people who used stimulants had increased odds of AMA discharge (aOR 1.83 (CI 1.73, 1.96)) and 30-day readmission (aOR 1.30 (95% CI 1.23, 1.37)). Multiple concomitant substance use disorders were associated with increased odds of AMA discharge and 30-day readmission. Conclusions: People with OUD have high rates of both AMA discharges and 30 day-readmissions, and there is a layered effect of increasing co-occurring SUDs leading to worse hospitalization outcomes. The heterogeneity of drug use patterns needs to be considered when developing strategies to improve health care outcomes for people with substance use disorder.