Trends in Attachment to a Primary Care Provider in Ontario 2008-2018: An Interrupted Time-Series Analysis

Context: Attachment to a regular primary care provider is associated with better health outcomes, but 15% of Canadians lack a consistent source of ongoing primary care.

Objective: To examine trends in primary care attachment in Ontario from 2008-2018, through an equity lens and in relation to policy changes in implementation of payment reforms and team based care.

Study Design and Analysis: Retrospective observational study using population level administrative data housed at ICES. We examined rates of patients attached to a regular primary care provider from April 1, 2008-Mar 31, 2019, and used segmented piecewise regression to examine changing trends before and after 2015, when physician entry to new payment and delivery models was restricted. We used multivariable logistic regression to model the association of patient characteristics and attachment in 2018, stratified by sex and adjusted for age, rurality, comorbidity, immigration status and the Residential Instability and Material Deprivation domains of the Ontario Marginalization Index.

Setting or Dataset: Linked administrative databases including health care registry, provider and enrolment data, and health care utilization.

Population Studied: Ontario residents eligible for universal health insurance between April 1, 2008-Mar 31, 2019.

Outcome Measures: Percentage of eligible Ontario residents attached to a primary care physician, measured with administrative data using a validated algorithm.

Results: Attachment increased from 80.5% (n=10,352,385) adults in 2008 to 88.9% of the population (n=12,537,172) in 2018. Attachment grew until 2014 (slope=1.47; p<0.0001), but was stagnant thereafter (slope =0.13, p=0.16). Attachment was lower among rural Ontarians, those with low comorbidity, highest residential instability, material deprivation and recent immigrants. Inequities narrowed for recent immigrants, males and people with lower incomes over the study period, but persistent disparities were seen in 2018 for all these groups.

Conclusions: Primary care attachment in Ontario increased between 2008 and 2014, but then was stalled. Lack of sustained progress was associated temporally with reduced physician entry to alternate funding and interdisciplinary team models. While disparities in attachment narrowed for many groups, persistent gaps remain for immigrants and lower income Ontarians. Targeted interventions are needed to address these persistent gaps.