Association of physician financial incentives with primary care enrolment of adults with serious mental illnesses in Ontario: a retrospective observational population-based study.

Background: Financial incentives may improve primary care access for adults with schizophrenia or bipolar disorder (serious mental illness [SMI]). We studied the association between receipt of the SMI financial premium paid to primary care physicians and rostering of adults with SMI in different patient enrolment models (PEMs), including enhanced fee-for-service and capitation-based models with and without interdisciplinary team-based care.

Methods: We conducted a retrospective cohort study involving Ontario adults (≥18 yr) with SMI in PEM practices, in fiscal years 2016/17 and 2017/18. Using negative binomial models, we examined relations between rostering and the primary care model and the contribution of the incentive. Similar models were developed for adults with type 1 or 2 diabetes mellitus and the general population.

Results: Among 9730 physicians in PEM practices, 4866 (50.0%) received a premium and 448 319 (88.4%) people with SMI in PEMs were rostered. Compared with enhanced fee for service, the likelihood of rostering people with SMI was 3.0% higher for patients in capitation with team-based care (adjusted relative risk [RR] 1.03, 95% confidence interval [CI] 1.02-1.04), with similar results for capitation without team-based care (adjusted RR 1.00 95% CI 0.99-1.01). Rostering for people with diabetes was similar in team-based care (adjusted RR 1.02, 95% CI 1.02-1.03) but higher in capitation without team-based care (adjusted RR 1.03, 95% CI 1.02-1.03) and slightly higher for the Ontario population (team-based care 1.04, 95% CI 1.04-1.05, capitation without team-based care 1.03, 95% CI 1.03-1.04).

Interpretation: Rostering of people with SMI was lower than for the general population. Additional policy measures are needed to address persisting inequities and to promote rostering of this underserved population with complex needs.