Presentation (CTI)

OBJECTIVES: The availability of anti-obesity medications (AOMs) has increased the need for population-level evidence on obesity. However, obesity is difficult to identify in Canadian administrative health data because body mass index is not routinely captured. This study described the annual frequency of adults with obesity or overweight indicators and their overlap in Alberta, Canada.
METHODS: A repeated cross-sectional study was conducted using linked administrative health data from Alberta, Canada, between April 2015 and March 2024. Adults (≥18 years) with at least one obesity/overweight indicator were identified annually using: (1) obesity diagnosis codes; (2) bariatric procedure codes; or (3) AOM dispensations. Individuals receiving semaglutide or tirzepatide with diabetes were excluded. Annual frequencies of each indicator and their overlap were described.
RESULTS: There were 552,374 unique individuals identified using at least one obesity or overweight indicator during the study period. The mean age at first encounter was 49.2 years and 60.3% were female. The annual frequency of individuals identified using AOMs increased from 2,496 in 2015/16 to 82,950 in 2023/24, while the frequency identified using diagnosis codes remained similar from 135,435 to125,887. Bariatric procedures were the least common, ranging from 802 in 2015/16 to 762 in 2023/24. Overlap between indicators was limited in earlier years but more substantial in more recent years, with the proportion of individuals receiving AOMs or bariatric procedure and having an obesity diagnosis code in the same or preceding fiscal year increasing from 1.5% in 2015/16 to 35.1% in 2023/24.
CONCLUSIONS: In an era of expanding use of AOMs, obesity diagnosis codes, bariatric procedures, and medication records identified distinct but overlapping populations in Alberta administrative data. Reliance on diagnosis codes alone may underestimate the population burden of obesity. Combining multiple indicators may improve identification of individuals with obesity and support future real-world studies evaluating obesity management and outcomes.