Comparing GPs’ antibiotic prescribing decisions to a clinical prediction rule: an online vignette study

BACKGROUND: The ‘STARWAVe’ clinical prediction rule (CPR) uses seven factors to guide risk assessment and antibiotic prescribing in children with cough (Short illness duration, Temperature, Age, Recession, Wheeze, Asthma, Vomiting). AIM: To assess the influence of STARWAVe factors on GPs’ unaided risk assessments and prescribing decisions. DESIGN AND SETTING: Clinical vignettes administered to 188 UK GPs online. METHOD: GPs were randomly assigned to view 32 (out of a possible 64) vignettes online depicting children with cough. The vignettes comprised the seven STARWAVe factors, which were varied systematically. For each vignette, GPs assessed risk of deterioration in one of two ways (sliding-scale versus risk-category selection) and indicated whether they would prescribe antibiotics. Finally, GPs saw an additional vignette, suggesting that the parent was concerned. Mixed-effects regressions were used to measure the influence of STARWAVe factors, risk-elicitation method, and parental concern on GPs’ assessments and decisions. RESULTS: Six STARWAVe risk factors correctly increased GPs’ risk assessments (bs(sliding-scale)≥0.66, odds ratios [ORs](category-selection)≥1.75, Ps≤0.001), whereas one incorrectly reduced them (short illness duration: b(sliding-scale) −0.30, OR(category-selection) 0.80, P≤0.039). Conversely, one STARWAVe factor increased prescribing odds (temperature: OR 5.22, P<0.001), whereas the rest either reduced them (short illness duration, age, and recession: ORs≤0.70, Ps<0.001) or had no significant impact (wheeze, asthma, and vomiting: Ps≥0.065). Parental concern increased risk assessments (b(sliding-scale) 1.29, OR(category-selection) 2.82, P≤0.003) but not prescribing odds (P = 0.378). CONCLUSION: GPs use some, but not all, STARWAVe factors when making unaided risk assessments and prescribing decisions. Such discrepancies must be considered when introducing CPRs to clinical practice.