Patterns of substance use before and after hospitalization among patients seen by an inpatient addiction consult service: A latent transition analysis

Background and aims: Polysubstance use is common and contributes to morbidity and mortality of hospitalized patients, and yet little is known about patterns of substance use among hospitalized patients, or how an addiction consult service (ACS) might impact polysubstance use after discharge. The objective of this study was to identify patterns of substance use at admission and after discharge among hospitalized patients with substance use disorders who saw an ACS. Design: Prospective cohort study. We used latent transition analysis of substance use scores at the time of hospital admission and 30 to 90 days posthospitalization. Setting: Single, academic health center with an ACS in Portland, Oregon, from 2015 to 2018. Participants/cases: Patients were eligible if they received a consult to the inpatient ACS. Measurements: We used Addiction Severity Index-Lite scores to capture self-reported substance use at baseline and follow-up for heroin, other opioid, alcohol, amphetamine, and cocaine. Findings: From 2015 to 2018, 486 individuals consented to participate. More than half of patients used more than one substance at baseline. Of those reporting any baseline opioid use, nearly three-quarters (n=187, 69.5%) had polysubstance use in the previous 30 days, including alcohol (n=80, 29.7%), cocaine (n=25, 9.3%), or amphetamine use (n=142, 52.8%). We identified three patterns of substance use at baseline: 1) alcohol use dominant, 2) polysubstance use dominant, and 3) heroin and other opioid use dominant. Patients transitioned along five trajectories to three different follow-up profiles that showed lower endorsement of all substances used. Slightly more than 40% (40.1%) of patients newly endorsed abstinence of at least one substance at follow-up. Conclusions: Polysubstance use is common in hospitalized patients with substance use disorders and identifying patterns of polysubstance use can guide clinical management. Hospital providers should prepare to manage polysubstance use during hospitalization and hospitals should broaden care beyond interventions for opioid use disorder.