The use of C-reactive protein testing and antibiotic prescribing in Italy: A population-based study in primary care.

Testing serum C-reactive protein (CRP) levels can help determine whether there is a need for antibiotics and can limit prescribing of antibiotics for illnesses that are likely viral or non-infectious in origin. Using Health Search, an Italian primary care database, we identified all patients, aged 15 years or older, being registered in the period between 1 January 2000 and 31 December 2019 and newly diagnosed with upper respiratory tract infections (URTIs) or 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 31 December 2019. The association between the CRP testing 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, 28 688 (6.11%) were prescribed with antibiotics because of the aforementioned indications. Of note, 98% of cases, nominally those prescribed with antibiotics, were not tested with CRP. However, those receiving antibiotics were more likely to have been previously tested for CRP than controls who did not receive antibiotics (833/28 601 [3%] and 4128/277 968 [1.5%]; OR 2.0 [95% CI: 1.8-2.1]). Our findings indicate that most of the antibiotic prescriptions for the investigated conditions were given without any prior CRP testing. A small minority of GPs did properly use CRP to determine whether antibiotics were needed. Further guidance is needed in Italy on the use of CRP in guiding antibiotic prescribing in primary care.