The impact of Choosing WiselyTM recommendations and insurance coverage restrictions on the provision of low-value care: an interrupted time series analysis of vitamin D tests

Interventions to reduce low-value care vary considerably in effectiveness. International consensus considers vitamin D blood testing in a general population as a low-value care intervention, which lead to its inclusion in the Swiss Choosing WiselyTM recommendation in April 2021. In mid-2022, the Swiss Public Health authorities further restricted basic health insurance coverage for the test. We conducted a retrospective analysis of health insurance claims data covering about 880’000 Swiss residents in the compulsory health insurance market. To assess the effects of a) the Choosing Wisely recommendation and b) the federal coverage restriction, we applied interrupted time series models at the physician level, controlling for seasonal effects, physician fixed effects, and patient characteristics. The Choosing Wisely recommendation reduced the average monthly number of tests prescribed per physician per 100 consultations by approximately 5.98% in the 12 months following the intervention. The national coverage restriction led to a significant 57.82% drop in vitamin D testing per physician per 100 consultations in the 6 months following the intervention. Medical recommendations marginally reduced low-value services, and their impact on clinical practice was limited. In contrast, federal coverage restrictions drastically reduced unnecessary testing. Multicomponent strategies combining evidence-based guidance for healthcare professionals, patient involvement, and national regulation related to reimbursement could be a best practice model for guiding public health stakeholders and politicians in order to reduce low-value care.