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DOI:
https://doi.org/10.57187/5204

Original article

Vol. 156 No. 9 (2026)

Impact of a national Smarter Medicine guideline on outpatient proton-pump inhibitor prescription in Switzerland: a nationwide interrupted time-series analysis

Cite this as:
Swiss Med Wkly. 2026;156:5204
Published
30.09.2026

Summary

BACKGROUND: Proton-pump inhibitors (PPI) are a key treatment for gastro-oesophageal disease, but their frequent overprescription leads to potential adverse effects and an economic burden. In this retrospective study, we investigated the effect of a Smarter Medicine guideline published in May 2014 by the Swiss Society of General Internal Medicine, which recommended that general practitioners should avoid “long-term treatment of gastrointestinal symptoms with proton-pump inhibitors without titrating to the lowest effective dose needed”.

METHODS: An interrupted time-series analysis was performed using a Seasonal AutoRegressive Integrated Moving Average (SARIMA) model, which was validated through a Bayesian Model Averaging algorithm with changepoint detection. National PPI sell-in data was provided by IQVIA and covered 100% of oral and intravenous PPIs distributed in Switzerland from 2009 to 2019. The main outcome was the monthly number of oral PPI defined daily doses (DDD) per 100,000 inhabitants aged ≥20 years. A regression analysis was conducted to estimate pre-guideline trend, post-guideline level change and post-guideline slope change. Using Bayesian Model Averaging, the probability of changepoint occurrence over time was calculated without predetermined intervention dates. Oral PPI DDDs were used as a surrogate for outpatient prescriptions, while intravenous PPI DDDs served as a control in Bayesian Model Averaging.

RESULTS: Following guideline publication, a significant post-guideline downward trend of oral PPI DDDs was observed (slope change, p <0.001). Bayesian analysis of oral PPI DDDs supported a single changepoint with 92% probability, most likely occurring within 2 years after guideline publication (79% summed changepoint occurrence probability). For intravenous DDDs, the probability of a single changepoint dropped to 41%, with only 29% summed probability for the same period.

CONCLUSIONS: A significant downward trend in PPI oral DDDs was observed after the Smarter Medicine guideline publication, suggesting that primary care guidelines have the potential to induce change in prescribing behaviour.

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