Vitamin D and Low-Value Care
Health systems continue to face the problem of low-value care, i.e. services that bring limited benefit to patients while adding costs and administrative effort. Vitamin D testing has become a prominent example.
Although clinical guidelines consistently advise against routine testing for low-risk individuals, the use of these tests has continued to rise in many countries. In Switzerland, testing rates almost doubled between 2013 and 2020, from 96 to 199 tests per 1000 inhabitants.
A Policy Response
This increase led to several policy measures. In April 2021, the Smarter Medicine initiative, which is the Swiss equivalent of Choosing Wisely™, included vitamin D testing in its list of procedures to avoid. The recommendation was simple: no routine measurement of 25(OH)-Vitamin D in patients without risk factors. Physicians were informed of these measures.
A year later, the Federal Office of Public Health introduced a coverage restriction, limiting reimbursement for such tests. Together, these steps offered a natural experiment to observe how clinical recommendations and financial incentives influence medical practice.
Using Real-World Data to Evaluate the Effect
To examine these changes, we analyzed mandatory health insurance claims data from SWICA, covering about 10% of the Swiss population. The data include more than 3’600 general practitioners and group practices, with adult patients who had at least one consultation between 2018 and 2023.
We applied interrupted time-series analysis to estimate how testing volumes evolved around the two interventions. The method compares observed data with a counterfactual trend, which shows what we would expect if the interventions had not taken place.
The models account for patient characteristics, clinical indications for testing based on Swiss guidelines, and physician-specific prescribing behavior. This allows us to isolate the effect of the policy interventions from broader temporal or compositional changes.
A Multi-Disciplinary Collaboration
This study is the result of a productive collaboration between the health services research team at SWICA, physicians at the Institute of Primary Care of the University of Zürich, and health economists at the Institute of Health Economics and Health Policy of the Bern University of Applied Sciences.
This collaboration demonstrates how insights from claims data can advance our understanding of the healthcare system and inform policy decisions aimed at reducing costs for the Swiss population.
This research has been published in BMC Health Services Research (October 2025) and is available here 👉(Sallin et al. 2025).
We model Vitamin D tests prescribed over time
Reading the Chart:
- **Observed data** from SWICA claims (3,600+ physicians)
- **Model predictions** based on our statistical analysisVitamin D Test Prescriptions Rose Despite Low-Value Status
Despite clear evidence of low clinical value, vitamin D test prescriptions rose by 20% between 2018 and 2021.
A textbook example of low-value care in the healthcare system (see also Obsan 2023).
April 2021: Smarter Medicine Takes Action
Switzerland’s Choosing Wisely™ campaign places vitamin D testing on their “Top 5” list of unnecessary procedures.
Clear message: “No routine testing for patients without risk factors.”
Clinical Recommendations: Modest Impact
The Smarter Medicine recommendation shows a slight downward trend.
But is this enough? Let’s compare with what would have happened without intervention…
Revealing the Counterfactual
The teal dashed line shows what would have happened without the recommendation.
Testing rates would have continued climbing upward.
The Numbers: Clinical Recommendations Work, But Modestly
Statistical analysis confirms a 4.9% reduction in testing rates [95% CI: -5.3%, -4.5%].
We conduct statistical tests to see whether the recommendation led to a recognizable pattern. The number of tests per consultation falls by 4.9% [-5.3%, -4.5%] after the recommendation.
July 2022: Financial Reality Hits
The Federal Office of Public Health restricts coverage. Patients now pay out-of-pocket for routine tests.
Financial Incentives: The Game Changer
Coverage restrictions deliver a 62% reduction in testing rates. This is a dramatic drop compared to clinical recommendations alone.
The number of tests per consultation falls by 62% [-62.4%, -61.6%] The 6-month cumulated effect is -60% [-60.0%, 59.0%].
The Bottom Line: 15.65 Million CHF Saved
Healthcare system savings of 15.65 million CHF in 2022 alone.
That’s 1.8 CHF per Swiss resident.
Key Findings and Policy Implications
Clinical recommendations alone proved less effective than government regulation in reducing low-value care in Switzerland—but our analysis revealed important nuances.
We found no unintended consequences from the coverage limitation: vitamin D supplementation rates remained unaffected, suggesting the policy successfully targeted testing without compromising appropriate treatment.
However, from a health policy perspective, simply removing procedures from basic insurance coverage cannot be the default solution for addressing unnecessary treatments. This regulatory approach creates administrative burden.
A more sustainable solution lies in strengthening financial incentives that align provider and payer interests. In Switzerland, this can be achieved through managed care contracts between physician networks and health insurers within alternative insurance models. These contracts establish quality standards while creating shared financial responsibility among physicians—encouraging appropriate care delivery without heavy-handed regulation.
References
Sallin, Aurélien, Daniel Ammann, Caroline Bähler, Tobias Müller, Stefan Neuner-Jehle, Oliver Senn, and Eva Blozik. 2025. “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.” BMC Health Services Research 25 (1): 1359.