OBJECTIVES: 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 three perspectives of healthcare, government, and society 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. Given a significant amount of cross-border shopping of sugary drinks in Norway, the cross-price effect resulting from new tax intervention was additionally accounted for in Stratified Analysis (SA). Model inputs were adopted from the best available real-world data published publicly. 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 may be overvalued in General Analysis (GA) when cross-border trade is 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 might be regarded as cost-effective. However, cross-border trade can negatively influence well-intended new SSB tax policy effect. Policymakers need to be aware of the potential policy resistance in real environment.