Predictors of no, low and frequent emergency department use for any medical reason among patients with cannabis-related disorders attending Quebec (Canada) addiction treatment centres.

Introduction: Patients with substance-related disorders and mental disorders (MD) contribute substantially to emergency department (ED) overcrowding. Few studies have identified predictors of ED use integrating service use correlates, particularly among patients with cannabis-related disorders (CRD). This study compared predictors of low (1-2 visits/year) or frequent (3+ visits/year) ED use with no ED use for a cohort of 9836 patients with CRD registered at Quebec (Canada) addiction treatment centres in 2012-2013.

Methods: This longitudinal study used multinomial logistic regression to evaluate clinical, sociodemographic and service use variables from various databases as predictors of the frequency of ED use for any medical reason in 2015-2016 among patients with CRD.

Results: Compared to non-ED users with CRD, frequent ED users included more women, rural residents, patients with serious MD and chronic CRD, dropouts from programs in addiction treatment centres and with less continuity of physician care. Compared with non-users, low ED users had more common MD and there more workers than students.

Discussion And Conclusions: Multimorbidity, including MD, chronic physical illnesses and other substance-related disorders than CRD, predicted more ED use and explained frequent use of outpatient services and prior specialised acute care, as did being 12-29 years, after controlling for all other covariates. Better continuity of physician care and reinforcement of programs like assertive community or integrated treatment, and chronic primary care models may protect against frequent ED use. Strategies like screening, brief intervention and treatment referral, including motivational therapy for preventing treatment dropout may also be expanded to decrease ED use.