Cost-effectiveness of a school-based health promotion program in Canada: A life-course modeling approach.

BACKGROUND: The Alberta Project Promoting active Living and healthy Eating in Schools (APPLE Schools) has been recognized as a "best practice" in preventing childhood obesity. To inform decision making on the economic implications of APPLE Schools and to justify investment, we evaluated the project's cost-effectiveness following a life-course approach. METHODS: We developed a state transition model for the lifetime progression of body weight status comparing elementary school students attending APPLE Schools and control schools. This model quantified the lifetime impact of APPLE Schools in terms of prevention of excess body weight, chronic disease and improved quality-adjusted life years (QALY), from a school system's cost perspective. Both costs and health outcomes were discounted to their present value using 3% discount rate. RESULTS: The incremental cost-effectiveness ratio(ICER) of APPLE schools was CA$33,421 per QALY gained, and CA$1,555, CA$1,709 and CA$14,218 per prevented person years of excess weight, obesity and chronic disease, respectively. These estimates show that APPLE Schools is cost effective at a threshold of ICER < CA$50,000. In probabilistic sensitivity analysis, APPLE Schools was cost effective more than 64% of the time per QALY gained, when using a threshold of ICER