Cost-Effectiveness Analysis of a Commercial Physical Activity App

Abstract

Background: Government interest in commercial physical activity apps has increased with little evidence of their cost-effectiveness. This is the first study to our knowledge to examine the cost-effectiveness of a commercial physical activity app (Carrot Rewards). Methods: A cost-effectiveness analysis was performed to calculate the incremental cost-effectiveness ratio (ICER) of Carrot Rewards compared to a no-intervention reference scenario using a five-year time horizon. An age-, sex-, and geography-dependent Markov model was developed assuming a public healthcare payer perspective. A closed cohort (n=38,452) representing the population reached in two Canadian provinces (British Columbia, Newfoundland & Labrador) at the time of a 12-month prospective study was used. Costs and effects were both discounted at 1.5% and expressed in 2015 Canadian dollars. Subgroup analyses were conducted to compare ICERs between provinces, sexes, age groups, and engagement levels. Findings: Carrot Rewards had an ICER of $11,113 CAD per quality adjusted life year (QALY), well below the $50,000 CAD per QALY willingness-to-pay (WTP) threshold. Subgroup analyses revealed that the app was more cost-effective for British Columbians, females, highly engaged users, and adults aged 35-64yrs, and was dominant for older adults (65+yrs). Deterministic sensitivity analyses revealed that the ICER was most influenced by the relative risk of diabetes. Probabilistic sensitivity analyses revealed varying parameter estimates predominantly resulted in ICERs below the WTP threshold. Interpretation: Carrot Rewards is cost-effective, and dominant for older adults. These results provide, for the first time, rigorous health economic evidence for a commercial physical activity app as part of public health programming. Funding Statement: Public Health Agency of Canada (PHAC) Multi-Sectoral Partnership Approach to Healthy Living and Chronic Disease Prevention, as well as the Baycrest’s Soupcoff Family Fellowship, Mitacs Elevate, Sandra Rotman Centre for Health Sector Strategy Fellowship, Social Sciences and Humanities Research Council Partnership Grants. Declaration of Interests: MM received consulting fees from Carrot Insights Inc. from 2015 to 2018 as well as travel reimbursement in January and March 2019. MM had stock options in the company as well but these are now void since Carrot Insights Inc. went out of business in June 2019. RR was employed as a research intern by Carrot Insights Inc. from March 2018 to July 2018. RR was a Mitacs postdoc from February 2019 to June 2019 MH and SS declare that they have no conflicts of interests. Ethics Approval Statement: Ethical approval for this study was provided by Western University’s Human Research Ethics Board (#113322). This study involved the secondary use of de-identified data. There was no consent for this secondary data analysis. However, app users were informed of and had to accept the app’s privacy policy describing how de-identified data may be used for reporting purposes and presented in aggregate.