Population

We identified all ambulatory in-person visits and virtual care visits using relevant physician billing codes. We excluded claims for patients who were not Ontario residents or who had an invalid or missing health card number. We captured all eligible physician visits, irrespective of specialty.

We further identified patients with ambulatory-care–sensitive conditions including chronic obstructive pulmonary disease, heart failure, asthma, hypertension and diabetes using existing ICES registries and previously published disease-identifying algorithms.^12–16 We identified patients with serious mental illness by at least 2 outpatient claims or 1 inpatient claim with the corresponding International Classification of Diseases, 9th revision (ICD-9) or International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) code for schizophrenia and psychotic disorders or bipolar disorder in the previous 12 months.¹⁷ We identified patients with angina by at least 1 emergency department visit with the relevant ICD-9 or ICD-10 code in the previous 12 months (Appendix 1, Supplemental Table S2).