Few studies have assessed the overall impact of outpatient service use on acute care use, comparing patients with different types of substance-related disorders (SRD) and multimorbidity. This study aimed to identify sociodemographic and clinical characteristics and outpatient service use that predicted both frequent ED use (3+ visits/year) and hospitalization among patients with SRD. Data emanated from 14 Quebec (Canada) addiction treatment centers. Quebec administrative health databases were analyzed for a cohort of 17,819 patients over a 7-year period. Multivariable logistic regression models were produced. Patients with polysubstance-related disorders, co-occurring SRD-mental disorders, severe chronic physical illnesses, and suicidal behaviors were at highest risk of both frequent ED use and hospitalization. Having a history of homelessness, residing in rural areas, and using more outpatient services also increased the risk of acute care use, whereas high continuity of physician care protected against acute care use. Serious health problems were the main predictor for increased risk of both frequent ED use and hospitalization among patients with SRD, whereas high continuity of care was a protective factor. Improved quality of care, motivational, outreach and crisis interventions, and more integrated and collaborative care are suggested for reducing acute care use.
Keywords: addiction treatment centers; frequent emergency department use; hospitalization; patient sociodemographic and clinical characteristics; patterns of service use; substance-related disorders.