A system-level study of initiation, engagement, and equity in outpatient substance use treatment.

Understanding the nature of variations in the quality of substance use treatment is critical to ensuring equity in service delivery and maximizing treatment effectiveness. We used adapted versions of the US Healthcare Effectiveness Data and Information Set (HEDIS) treatment initiation and engagement measures to assess care quality in specialized outpatient services for substance use in Ontario, Canada. Using administrative data, we calculated rates of outpatient treatment initiation and engagement (N = 120,394 episodes) and investigated variation by client characteristics and treatment mandates. About half of clients who entered outpatient treatment met the criteria for initiation (i.e., had a second visit within 14 days) and 30% met the criteria for engagement (i.e., had another two visits within 30 days of initiation). The likelihood of treatment initiation and engagement was greater among older people, those with more education, those who were not mandated to enter treatment, and those with greater substance use at admission. People who entered treatment for cannabis were less likely to engage. Engagement was less likely among men than women, but gender differences were slight overall. This study demonstrates the feasibility of using adapted versions of two common measures to characterise care quality in substance use treatment services in the Canadian context. Overall, the magnitude of associations with client characteristics were quite small, suggesting that initiation and engagement were not overly localized to specific client subgroups. Findings suggest that the Ontario system has difficulty retaining clients who enter treatment and that most outpatient treatment involves care episodes of limited duration.