Prescribing antibiotics: the use of diagnostic tests in general practice. A register-based study

Objective: To assess (i) the pattern of antibiotic prescribing in Danish general practice, (ii) the use of diagnostic tests [point-of-care (POC) and tests analysed at the hospital laboratory (laboratory tests)], and (iii) the frequency of diagnostic testing in relation to antibiotic prescriptions. Design: Retrospective cross-sectional register-based study. Setting: General practice in a geographical area of Denmark covering 455,956 inhabitants. Subjects: We studied redeemed antibiotic prescriptions and performed diagnostic tests in general practice from 2013 to 2017 among inhabitants in nine selected municipalities. Main outcome measures: Frequency of antibiotic courses. Frequency and type of diagnostic testing performed in relation to types of antibiotics. Results: A total of 783,252 antibiotic courses were redeemed from general practice with an overall decrease of 19% during 2013–2017. Diagnostic testing increased by 6% during this period. POC tests comprised the majority of performed diagnostic tests (83%) with C-reactive protein (CRP) as the most frequently used test. A 27% increase in the use of laboratory tests was observed. Tests were performed in relation to 43% of all antibiotic courses; most in relation to prescriptions for sulphonamide and trimethoprim (57%) and rarely when prescribing tetracyclines (10%). Conflicting with national guidelines, Danish GPs prescribed fluoroquinolones without performing any kind of diagnostic testing in 48% of the cases. Conclusions: This study provides an overview of the use of diagnostic tests in relation to antibiotics and creates basis for further research into the variability between types of antibiotics. The study indicates that there is room for improvement to use diagnostic tests as an aid to promote prudent antibiotic use.KEY POINTS Diagnostic tests (point-of-care or tests analysed at the hospital laboratory), can increase diagnostic certainty and lead to a reduction in antibiotic use in general practice. A decrease in antibiotic courses in general practice in Denmark was observed during 2013–2017, while the use of diagnostic tests increased. A diagnostic test was performed in relation to 43% of antibiotic courses. Only 52% of prescribed fluoroquinolones was related to a diagnostic test, conflicting with national guidelines.