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.