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

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).

Percentage of physicians who self-declare adoption of the new acute respiratory infection (ARI) guidelines (i.e., treating patients according to the guidelines).

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.

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.

Multilevel regression coefficients estimating differences in antibiotic use (DDD per 1000 consultations) according to physician, practice, QC, walk-in clinic and patient characteristics.

Number of C-reactive protein (CRP) measurements, blood counts, and chest radiographs per 1000 consultations.

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).

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).

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).

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).

Perceived appropriateness of the CRP flowchart, measured using a French translation of "Intervention Appropriateness Measure" (5-point Likert scale, higher score means better outcome).

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).

Perceived appropriateness of shared decision-making, measured using a French translation of "Intervention Appropriateness Measure" (5-point Likert scale, higher score means better outcome).

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).

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).

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).

Perceived feasibility of shared decision-making, measured using a French translation of "Feasibility of Intervention Measure" (5-point Likert scale).

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).

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.

Fidelity to the CRP flowchart of the new ARI guidelines, using custom questions.

Fidelity to shared decision-making of the new ARI guidelines, using custom questions.

Anticipated sustainment of the new ARI guidelines, using custom questions.

Intended adoption of implementation strategies, measured with custom questions (5-point Likert scale, higher score is higher intention to adopt).

Adoption of implementation strategies, measured with custom questions (single answer, yes/no).

Fidelity of delivering the implementation strategies as intended, using custom questions.

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).

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).

Determinants of adoption of the ARI guidelines identified through quantitative and potentially qualitative data collection.

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).

Incremental cost-effectiveness ratio (ICER), expressed in CHF per percentage point reduction in antibiotic prescribing, comparing the ARI guideline implementation strategy to routine practice.