Novel Insights from Stratified Cost-Effectiveness Analysis of Sugar-Sweetened Beverage Tax Policy in Norway: A Comparative Modeling Study

BACKGROUND: The sugar-sweetened beverage (SSB) tax in Norway has changed remarkably over the past few years. The resultant health and economic effects are of concern to multiple stakeholders, such as the public, scholars, and health policymakers. OBJECTIVE: This study aims to comprehensively evaluate the cost-effectiveness of the incremental SSB tax in Norway in 2018, compared to the prior tax level in 2017, from healthcare, government, and societal perspectives over a lifetime horizon. METHODS: A Markov cohort model was employed to estimate incremental changes in both costs and health outcomes (i.e., life years) for a Norwegian birth cohort in 2018 by incorporating the best available real-world data. Given a significant amount of cross-border shopping of sugary drinks in Norway, the cross-price effect resulting from new tax intervention was accounted for in Stratified Analysis (SA). Deterministic sensitivity analyses were also performed to check the robustness of analysis results. RESULTS: Compared with SA, simulation results demonstrated that the estimated health gains and cost savings might be overvalued in General Analysis (GA) when the cross-border trade was not considered. In detail, the new tax intervention in 2018 was expected to save approximately 201 life years for males and 223 life years for females in GA, versus about 130 and 144 life years respectively in SA. Incremental costs spread broadly from -NOK 93 million to -NOK 15 million in GA and between -NOK 40 million and NOK 37 million in SA. Of note is the unexpectedly positive incremental costs from the societal perspective in SA. CONCLUSIONS: The new SSB tax intervention in Norway in 2018 can be regarded as cost-effective. However, cross-border trade could negatively influence well-intended new SSB tax policy effect. Policymakers need to be aware of the potential policy resistance in real environment