ESTIMATING THE BURDEN OF OBESITY IN CANADA USING US CLAIMS DATA: A CROSS-NATIONAL REAL-WORLD EVIDENCE APPROACH
Author(s)
Tuhin Maity, PhD1, Saina Sehatkarlangrodi, PhD1, Vance MacDonald, BS2, Katalina Chan, PharmD2.
1Real World Evidence & Insights, McKesson Canada, Mississauga, ON, Canada, 2Novo Nordisk Canada Inc., Mississauga, ON, Canada.
1Real World Evidence & Insights, McKesson Canada, Mississauga, ON, Canada, 2Novo Nordisk Canada Inc., Mississauga, ON, Canada.
OBJECTIVES: Obesity imposes a substantial yet incompletely characterized economic burden on the Canadian healthcare system. Existing Canadian data sources lack the clinical granularity, end-to-end coverage, and sample size needed to produce stable cost estimates across age, sex, and BMI subgroups, limiting evidence-informed decision-making. This study aimed to produce robust, policy-relevant estimates of direct Canadian healthcare costs of obesity by leveraging large, longitudinal data from another jurisdiction and systematically Canadianizing the results.
METHODS: We analyzed approximately 200 million medical and pharmacy claims from McKesson CompileTM, representing 8.5 million unique individuals in the United States. Cohorts were defined across five BMI categories (normal weight, overweight, and obesity classes 1-3), six age bands (18-34 through ≥75 years), and sex, yielding 60 demographic-BMI strata. Each cohort was calibrated to Canadian population characteristics using two co‑primary methods: inverse probability weighting and covariate‑mean calibration matching. Medical and pharmacy costs were converted to Canadian equivalents by mapping claims to Canadian comparators and applying cohort‑specific conversion factors.
RESULTS: Higher BMI and age were consistently associated with increased estimated total (pharmacy + medical) direct healthcare costs, ranging from approximately CAD $3,700 per person-year for females aged 18-34 with normal weight to nearly CAD $19,000 for females aged 55-64 with class 2 obesity. Pharmacy spending was the dominant cost component, accounting for about 61% of total costs overall and 70-80% in the highest-cost midlife obesity cohorts. The highest medical costs were consistently observed in individuals with class 2 obesity across both males and females. Results from the two independent methods showed strong convergence, supporting the robustness of the Canadianization approach.
CONCLUSIONS: These findings provide a transparent, data‑driven foundation to inform benefit design, formulary decisions, and cost‑effectiveness evaluations of obesity therapies in Canada, supporting prioritization of pharmaceutical interventions for working‑age adults with moderate to severe obesity.
METHODS: We analyzed approximately 200 million medical and pharmacy claims from McKesson CompileTM, representing 8.5 million unique individuals in the United States. Cohorts were defined across five BMI categories (normal weight, overweight, and obesity classes 1-3), six age bands (18-34 through ≥75 years), and sex, yielding 60 demographic-BMI strata. Each cohort was calibrated to Canadian population characteristics using two co‑primary methods: inverse probability weighting and covariate‑mean calibration matching. Medical and pharmacy costs were converted to Canadian equivalents by mapping claims to Canadian comparators and applying cohort‑specific conversion factors.
RESULTS: Higher BMI and age were consistently associated with increased estimated total (pharmacy + medical) direct healthcare costs, ranging from approximately CAD $3,700 per person-year for females aged 18-34 with normal weight to nearly CAD $19,000 for females aged 55-64 with class 2 obesity. Pharmacy spending was the dominant cost component, accounting for about 61% of total costs overall and 70-80% in the highest-cost midlife obesity cohorts. The highest medical costs were consistently observed in individuals with class 2 obesity across both males and females. Results from the two independent methods showed strong convergence, supporting the robustness of the Canadianization approach.
CONCLUSIONS: These findings provide a transparent, data‑driven foundation to inform benefit design, formulary decisions, and cost‑effectiveness evaluations of obesity therapies in Canada, supporting prioritization of pharmaceutical interventions for working‑age adults with moderate to severe obesity.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
EE638
Topic
Economic Evaluation, Methodological & Statistical Research, Study Approaches
Topic Subcategory
Cost/Cost of Illness/Resource Use Studies
Disease
Diabetes/Endocrine/Metabolic Disorders (including obesity), No Additional Disease & Conditions/Specialized Treatment Areas