A national atlas to improve the study of Canadians living with long COVID (post-COVID-19 condition).

Objectives: To develop a national atlas of (1) Canadian cohorts studying or with the potential to study adults living with long COVID (LC) and (2) harmonize provincial and territorial administrative datasets to facilitate the creation of validated case-ascertainment algorithms and foster national collaboration on LC research.

Methods: We conducted a multifaceted environmental scan that included a comprehensive literature search and a survey of members of Canada's national LC research network between August 21, 2023, and November 10, 2023. We identified provincial and territorial cohorts, including those that were linkable to administrative data and common data elements among administrative datasets.

Results: We included 19 Canadian cohorts from five provinces (Alberta, British Columbia, Manitoba, Ontario, and Québec) containing data on over 580,000 adults. The majority of the cohorts measured sociodemographic data (e.g., age, sex) and measures of healthcare use, whereas equity-related measures such as gender, ethnicity, and race were limited. There was wide variability in the definitions of LC used across all cohorts. Comparable population-level administrative data are currently available in Alberta, British Columbia, Manitoba, Ontario, Québec, New Brunswick, Newfoundland and Labrador, Nova Scotia, and Saskatchewan.

Conclusion: Canada has a rich repository of LC datasets that are limited by variable definitions of LC and inadequate equity-related measures such as gender, ethnicity, and race. Standardization and diversification of these measures will facilitate efforts to study healthcare use and develop health policy to improve the care of Canadian adults living with LC at a population level.