The use of CRP testing and prescription of antibiotic therapy: a population-based study in primary care

The C-reactive protein (CRP) can guide the antibiotic prescription for infectious diseases which are likely viral. We identified all patients, aged 15 years or older, being registered in the database between January, 1, 2000 and December, 31, 2019 and newly diagnosed with upper respiratory tract infections (URTIs), COPD- or asthma-related exacerbations. From the date of these diagnoses, patients were followed up until occurrence of antibiotic prescription (for these indications) up to December 31, 2019. The association between the prescription of CRP and the outcome was investigated using a nested case-control analysis. In a cohort of 469,684 patients being diagnosed for URTI (83%), COPD- (11%) and asthma (7%)-related exacerbations, 28688 (6.11%) were prescribed with antibiotics because of the aforementioned indications. Of note, 98% of cases were not tested with CRP. Those receiving antibiotics showed a greater propensity to be previously tested for CRP than related controls. Our findings indicate that most of the antibiotic prescriptions for the investigated conditions did not report prior evaluation of CRP values. Nevertheless, it seems that some GPs properly used CRP before deciding for an antibiotic therapy. Further information and incentives in using CRP test should be therefore sustained in primary care.