Emergency Department Use and Enrollment in a Medical Home Providing After-Hours Care.

PURPOSE Compared with other high-income countries, Canada and the United States have among the highest rates of emergency department use and the lowest rates of primary care physicians reporting arrangements for after-hours care. We assessed whether enrollment in a medical home mandated to provide after-hours care in Ontario, Canada, was associated with reduced emergency department use. METHODS We conducted a retrospective cohort study using linked administrative data. We included all adult Ontarians enrolled in a medical home between April 1, 2005, and March 31, 2012, who had a minimum of 3 years of outcome data before and after enrollment (N = 2,945,087). We performed a linear segmented analysis with patient-level data to understand the association between initial enrollment in a medical home and emergency department visits, the proportion of all primary care visits occurring on the weekend, and the primary care visit rate. Age, income quintile, comorbidity, and morbidity were included in the modeling as time-varying covariates and sex as a stable variable. RESULTS The emergency department visit rate increased by 0.8% (95% CI, 0.7% to 0.9%) per year before medical home enrollment and by 1.5% (95% CI, 1.4% to 1.5%) per year after the transition. Enrollment in a medical home was associated with an increase in the proportion of visits that occurred on weekends, but a decrease in the overall primary care visit rate. CONCLUSIONS Enrollment of adult Ontarians in a primary care medical home offering after-hours care was not associated with a reduction in emergency department use. It will therefore be important to prospectively evaluate policy reforms aimed at improving access to primary care outside of conventional hours.