Background: Antibiotics are over-prescribed for respiratory tract infections in Australia.
Objectives: The aim of this study was to describe the clinical predictors of GPs' prescribing of antibiotics.
Methods: We used Clinical Judgment Analysis to study the responses of GPs to hypothetical paper-based vignettes of a 20-year-old with a respiratory tract infection. The nature of four symptoms and signs (colour of nasal mucous discharge; soreness of the throat; presence of fever; and whether any cough was productive of sputum) was varied and their effect on prescribing measured using logistic regression.
Results: Twenty GPs participated. The nature of each symptom and sign significantly predicted prescribing of an antibiotic. Cough productive of yellow sputum; presence of sore throat; fever; and coloured nasal mucus increased the probability of an antibiotic being prescribed.
Conclusions: GPs are influenced by clinical signs and symptoms to use antibiotics for respiratory infections for which there is poor evidence of efficacy from the literature.