Effectiveness and Implementation of a National Guideline for Acute Respiratory Tract Infections to Reduce Antibiotic Prescribing in Swiss Primary Care (ImpProGUIDE)

Effectiveness and Implementation of a National Guideline for Acute Respiratory Tract Infections to Reduce Antibiotic Prescribing in Swiss Primary Care: the ImpProGUIDE Hybrid Type II Effectiveness-implementation Trial

The ImpProGUIDE study aims to find out whether implementing new Swiss national guidelines for acute respiratory infections (ARI) can help to reduce antibiotic prescribing in primary care. In Switzerland, most antibiotics are prescribed in outpatient care, and many of these prescriptions may not be needed - especially when infections are caused by viruses, which antibiotics do not treat. Reducing overuse of antibiotics is important to slow the spread of antibiotic resistance.

The new guidelines were developed by the Swiss Society for Infectious Diseases (SSI) to support family doctors in managing ARIs, based on a syndromic approach. They recommend the targeted use of point-of-care C-reactive protein (CRP) testing when bacterial infection is suspected, as well as shared decision-making with patients.

This study will be carried out in quality circles (QCs) - small groups of family doctors who meet regularly to discuss and improve clinical practice - and in walk-in clinics in French- and Italian-speaking regions of Switzerland. Each will be randomly assigned to either an "intervention" group or a "control" group.

In the intervention group, QC moderators and medical center directors will receive implementation resources to lead a session and distribute materials to their group in autumn 2025 on the new guidelines. Doctors can then decide whether or not to use the recommendations in their consultations.

In the control group, QCs and centers will continue their regular activities. They will receive access to the same educational materials later, in summer 2026.

Throughout the study, the researchers will collect de-identified data from health insurance billing records to track antibiotic prescribing and the use of diagnostic tests. Doctors and QC moderators will also be invited to complete short online surveys twice a year (10-15 minutes) and may be asked to join optional interviews or group discussions after the winter season.

The study will also explore the effectiveness of the implementation strategies on the adoption of the SSI guidelines, as well as the barriers and facilitators to adoption. This study type is known as a hybrid effectiveness implementation study, simultaneously evaluating an intervention's impact on antibiotic prescribing and the strategies used to implement the new national guidelines in a real-world setting.

Participation in the study is voluntary. Doctors can withdraw at any time. All data will be handled confidentially and in line with Swiss data protection laws.

The study is funded by the Swiss National Science Foundation. No support is received from pharmaceutical companies or manufacturers of diagnostic tests.

Study Overview

• Status: Recruiting
• Conditions: Acute Respiratory Infection; Influenza-like Illness
• Intervention / Treatment: Behavioral: Training Session on acute respiratory infection guideline within a multifaceted implementation strategy

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jelena Dunaiceva, MPH; Phone Number: +41 78 654 23 74; Email: jelena.dunaiceva@unisante.ch; imppro@unisante.ch

Study Locations

• Switzerland
  • Canton of Vaud
    • Lausanne, Canton of Vaud, Switzerland, 1011
      • Recruiting
      • Unisanté
      • Contact: Jelena Dunaiceva, MPH; Phone Number: +41 78 654 23 75; Email: jelena.dunaiceva@unisante.ch
      • Principal Investigator: Yolanda Mueller, MD, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria for quality circles (QCs)

• Willing to participate in a study mainly conducted in French
• Agreeing to participate in evaluation surveys

Exclusion criteria for QCs*

- Not having any physician included in the study

Inclusion criteria for walk-in clinics

• The clinic offers general practice/primary care medicine consultations, including emergencies
• The clinic includes at least five physicians
• The clinic has an "Admission to practice charged to Swiss compulsory health insurance"
• The clinic plans to still be active in April 2026
• Located in one of the following cantons: Vaud, Geneva, Valais, Fribourg, Jura, Neuchatel, Bern, Ticino.
• Serving mainly adult patients
• Willing to participate in the study

Physicians in QCs fulfilling all of the following inclusion criteria are eligible for the study:

• Registered primary care physicians
• Specialist title in general internal medicine or practicing physician.
• Practicing in one of the following cantons: Vaud, Geneva, Valais, Fribourg, Jura, Neuchatel, Bern, Ticino.
• Participating in a QC or working in an outpatient clinic participating in the study*.
• Willing to participate in a study mainly conducted in French.
• Agreeing to participate in evaluation surveys and agreeing to be invited to interviews

Eligibility criteria for physicians in clinics :

- Having a clinical activity as primary care physician or supervising clinical activity of physicians in post-graduate training within a clinic included in the study

The only exclusion criterion for physicians is planning to retire before April 2026.

*Note: not all physicians from a QC or a clinic are expected or required to participate individually in the study, but at least one should participate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Acute respiratory infection guideline implementation; Quality circles (QC) and walk-in clinics randomized to the intervention arm will receive an overarching multifaceted implementation strategy for the new acute respiratory infection (ARI) guidelines. This includes educational materials to help the QC moderators or the person responsible for education in the clinic to lead a thematic session in autumn 2025, focusing on the use of a syndromic approach, targeted C-reactive protein (CRP) testing when bacterial infection is suspected, and shared decision-making with patients. Other facets include an information sheet and pocket card for physicians, and patient leaflets on acute cough.	Behavioral: Training Session on acute respiratory infection guideline within a multifaceted implementation strategy; Implementation strategies are deployed within quality circles, consisting of a structured educational session including a PowerPoint presentation, a facilitation guide, clinical vignettes, and printed materials for physicians and patients. The session is designed to support clinical decision-making about antibiotic use for ARI, based on targeted use of CRP and shared decision-making.
No Intervention: Usual care; QCs and walk-in clinics randomized to the control arm will continue their routine activities without receiving the educational materials on the new guidelines during the initial phase. In the summer 2026, these groups will be offered the same training materials provided to the intervention arm, with the option to use them in their QC sessions or internal training.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Defined daily doses of antibiotics commonly used for acute respiratory infections per 1000 consultations	Defined daily doses (DDD) of selected antibiotics (amoxicillin, co-amoxicillin, clarithromycin, azithromycin) per 1000 consultations, based on de-identified health insurance billing data. These antibiotics represent those most commonly prescribed for pneumonia, acute bronchitis, and upper respiratory tract infections (excluding pharyngitis, sinusitis, and otitis media).	Over the influenza-like illness (ILI) season (6 months).
Penetration of acute respiratory infection guidelines	Percentage of physicians who self-declare adoption of the new acute respiratory infection (ARI) guidelines (i.e., treating patients according to the guidelines).	Baseline and after 6 months.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Monthly antibiotic prescribing rate	Monthly prescribing rates expressed as: (1) DDD of antibiotics commonly used for ARI per 1000 consultations, and (2) DDD of total antibiotics per 1000 consultations.	Monthly for 12 months.
Model-estimated differences in antibiotic use	Multilevel regression coefficients estimating differences in antibiotic use (DDD per 1000 consultations) according to physician, practice, quality circle (QC), walk-in clinic, and patient characteristics.	Over the ILI season (6 months).
Model-estimated differences in antibiotic use	Multilevel regression coefficients estimating differences in antibiotic use (DDD per 1000 consultations) according to physician, practice, QC, walk-in clinic and patient characteristics.	Over 12 months.
Use of diagnostic tests	Number of C-reactive protein (CRP) measurements, blood counts, and chest radiographs per 1000 consultations.	Over the ILI season (6 months).
Perceived acceptability of the CRP flowchart	Perceived acceptability of the CRP flowchart, measured using a French translation of the "Acceptability of Intervention Measure" (5-point Likert scale, higher score means better outcome).	Baseline and after 6 months.
Perceived acceptability of the CRP flowchart assessed by custom questions	Perceived acceptability of the CRP flowchart, assessed using study-specific custom questions (e.g. "I generally agree with prescribing antibiotics in patients with an acute respiratory infection and a CRP level ≥ 100 mg/L." (question originally asked in French), with answer options according to a 5-point Likert scale, higher scores indicate better outcomes).	Baseline and after 6 months.
Perceived acceptability of shared decision-making	Perceived acceptability of shared decision-making, measured using a French translation of the "Acceptability of Intervention Measure" (5-point Likert scale, higher score means better outcome).	Baseline and after 6 months.
Perceived acceptability of shared decision-making assessed by custom questions	Perceived acceptability of shared decision-making, assessed using study-specific custom questions (e.g. "I appreciate the Consultation Support Tool for shared decision-making." (question originally asked in French), with answer options according to a 5-point Likert scale; higher scores indicate better outcomes).	Baseline and after 6 months.
Perceived appropriateness of the CRP flowchart	Perceived appropriateness of the CRP flowchart, measured using a French translation of "Intervention Appropriateness Measure" (5-point Likert scale, higher score means better outcome).	Baseline and after 6 months.
Perceived appropriateness of the CRP flowchart assessed by custom questions	Perceived appropriateness of the CRP flowchart, assessed using study-specific custom questions (e.g. "The CRP decision tree corresponds to the patient population in my practice/medical center." (question originally asked in French), with answer options according to a 5-point Likert scale, higher scores indicate better outcomes).	Baseline and after 6 months.
Perceived appropriateness of shared decision-making	Perceived appropriateness of shared decision-making, measured using a French translation of "Intervention Appropriateness Measure" (5-point Likert scale, higher score means better outcome).	Baseline and after 6 months.
Perceived appropriateness of shared decision-making assessed by custom questions	Perceived appropriateness of shared decision-making, assessed using study-specific custom questions (e.g. "Shared decision-making in patients with an acute respiratory infection and a CRP level ≥ 50 mg/L and < 100 mg/L corresponds to the patient population in my practice/medical center." (question originally asked in French), with answer options according to a 5-point Likert scale, higher scores indicate better outcomes).	Baseline and after 6 months.
Perceived feasibility of the CRP flowchart	Perceived feasibility of the CRP flowchart, measured using a French translation of "Feasibility of Intervention Measure" (5-point Likert scale, higher score means better outcome).	Baseline and after 6 months.
Perceived feasibility of the CRP flowchart assessed by custom questions	Perceived feasibility of the CRP flowchart, assessed using study-specific custom questions (e.g. "CRP testing in patients with an acute respiratory infection can be performed within a reasonable timeframe." (question originally asked in French), with answer options according to a 5-point Likert scale, higher scores indicate better outcomes).	Baseline and after 6 months.
Perceived feasibility of shared decision-making	Perceived feasibility of shared decision-making, measured using a French translation of "Feasibility of Intervention Measure" (5-point Likert scale).	Baseline and after 6 months.
Perceived feasibility of shared decision-making assessed by custom questions	Perceived feasibility of shared decision-making, assessed using study-specific custom questions (e.g. "Shared decision-making in patients with an acute respiratory infection and a CRP level ≥ 50 mg/L and < 100 mg/L takes too much time." (question originally asked in French), with answer options according to a 5-point Likert scale, higher scores indicate better outcomes).	Baseline and after 6 months.
Intended adoption of acute respiratory infection guidelines	Intended adoption of the new ARI guideline using custom questions. Intended adoption of the CRP flowchart using custom questions. Intended adoption of shared decision-making using custom questions.	Baseline and after 6 months.
Fidelity to C-reactive protein	Fidelity to the CRP flowchart of the new ARI guidelines, using custom questions.	Baseline and after 6 months.
Fidelity to shared decision-making	Fidelity to shared decision-making of the new ARI guidelines, using custom questions.	Baseline and after 6 months.
Anticipated sustainment of acute repiratory infection guidelines	Anticipated sustainment of the new ARI guidelines, using custom questions.	Baseline and after 6 months.
Intended adoption of implementation strategies	Intended adoption of implementation strategies, measured with custom questions (5-point Likert scale, higher score is higher intention to adopt).	Baseline and after 6 months.
Adoption of implementation strategies	Adoption of implementation strategies, measured with custom questions (single answer, yes/no).	Baseline and after 6 months.
Appropriateness of implementation strategies	Perceived appropriateness of implementation strategies delivered through and outside QCs, measured with custom questions (5-point Likert scale, higher score is higher appropriateness).	Baseline and after 6 months.
Fidelity in delivering the implementation strategies	Fidelity of delivering the implementation strategies as intended, using custom questions.	During the ILI season (6 months).
Acceptability of moderator implementation materials	Acceptability of implementation materials for moderators, measured with the instrument "Acceptability of Intervention Measure" (5-point Likert scale, higher score means better outcome) and additional custom question(s).	During the ILI season (6 months).
Acceptability of physician implementation materials	Acceptability of implementation materials for physicians, measured with the instrument "Acceptability of Intervention Measure" (5-point Likert scale, higher score means better outcome) and additional custom question(s).	During the ILI season (6 months).
Contextual and individual determinants of adoption	Determinants of adoption of the ARI guidelines identified through qualitative interviews, focus groups, and potentially quantitative data collection.	Within 6 months after the ILI season.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knowledge about acute respiratory infection management	Knowledge about ARI management according to the new guidelines, measured with a custom questionnaire: "Knowledge questionnaire on the diagnosis and treatment of acute respiratory infections and influenza-like syndromes", (6 questions, of which 3 multiple choice, 3 single choice).	Baseline and after 6 months.
Cost-effectiveness of ARI guideline implementation	Incremental cost-effectiveness ratio (ICER), expressed in CHF per percentage point reduction in antibiotic prescribing, comparing the ARI guideline implementation strategy to routine practice.	Over the ILI season (6 months).

Collaborators and Investigators

• Sponsor: Center for Primary Care and Public Health (Unisante), University of Lausanne, Switzerland
• Collaborators: Swiss Pharmacy Association, pharmaSuisse; University of Zurich, Institute for Implementation Science in Health care; Anresis, Swiss Centre for Antibiotic Resistance, University of Bern, Switzerland; CHUV, Lausanne University Hospitals, Switzerland
• Investigators: Principal Investigator: Yolanda Mueller, MD, PhD, Unisanté, Centre for Primary care and Public Health & University of Lausanne, Switzerland

Publications and helpful links

General Publications

• Wolfensberger A, Gendolla SC, Dunaiceva J, Pluss-Suard C, Niquille A, Nicolet A, Marti J, Powell BJ, Naef R, Boillat-Blanco N, Mueller Y, Clack L. Systematic method for developing tailored strategies for implementing point-of-care procalcitonin testing to guide antibiotic prescribing in Swiss primary care: a protocol for a mixed-methods participatory approach. BMJ Open. 2025 Mar 5;15(3):e091285. doi: 10.1136/bmjopen-2024-091285.

Helpful Links

• Description of the study on Unisanté webpage that includes the information sheet for study participants
• Description of the project on the website of Swiss National Science Foundation

Study record dates

Study Major Dates

• Study Start (Actual): May 19, 2025
• Primary Completion (Estimated): April 1, 2026
• Study Completion (Estimated): November 1, 2026

Study Registration Dates

• First Submitted: November 18, 2025
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 9, 2026

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: guidelines; primary care; shared decision making; outpatient; antimicrobial stewardship; antibiotics; implementation; family medicine; antimicrobial resistance; CRP; c-reactive protein; hybrid design; general medicine; effectiveness-implementation study; antibiotic prescribing
• Other Study ID Numbers: Req-2024-00897; 212429 (Other Grant/Funding Number: Swiss National Science Foundation)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

The non-identifiable data from the physician and moderator surveys, excluding free-text items, will be shared on the institutional data repository data.unisante.ch under the license CC-BY in open access mode. The ownership of these data will be joint between Unisanté and IFIS.

Billing data cannot be shared due to intellectual property rights and restrictions on reuse of the data.

Qualitative data from Institute for Implementation Science in Healthcare, University of Zurich (interview data (audio/video files, transcripts)) will not be shared, as the risk of identification remains even after removing names, affiliations and other direct identifiers.

Non-identifiable quotes of the interview partner, frequencies of codes, or processed/aggregated data will be shared upon reasonable request. These data will not be stored on a data repository as the effort to process data is not considered in proportion to the likelihood that this data will be requested from other research groups.

• IPD Sharing Time Frame: Individual participant data (IPD) from physician questionnaires (excluding free-text responses) will be available via the Unisanté open-access repository starting approximately 12 months after the final data collection (estimated for mid-2027). Data will remain accessible for at least 10 years, after which it will be evaluated for long-term archiving.
• IPD Sharing Access Criteria: Any researcher will be able to access the non-identifiable IPD from physician questionnaires (excluding free-text) and related documentation via the Unisanté open-data repository. Data will be shared in open and original formats (.csv and others) under a CC-BY license. All other data, including interview materials and SASIS datasets, will not be shared due to confidentiality requirements or legal restrictions.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No