Researchers assessed whether enrollment in a medical home mandated to provide after-hours care in Ontario, Canada, was associated with reduced emergency department use. 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.

They conducted a retrospective cohort study using linked administrative data. They 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).

Patient-Level Data

They 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.

ED Visit Rate

Age, income quintile, comorbidity, and morbidity were included in the modeling as time-varying covariates and sex as a stable variable. 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.

Medical Home

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. They found that in the Canadian province of Ontario, enrollment in a medical home with mandatory after-hours provision was associated with a small increase in the emergency department visit rate by adults.

This change occurred despite an increase in the crude number of primary care weekend billings during the time period and an associated increase in the proportion of all primary care visits that were on the weekend.

After-Hours Primary Care

The volume of after-hours primary care visits was sufficiently high to theoretically affect emergency department visit rates. They found that enrollment in a medical home was also associated with a decrease in the overall primary care visit rate but a small increase in continuity of care.

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.