Aetiology and prediction of pneumonia in lower respiratory tract infection in primary care

Knowledge of predominant pathogens and their association with outcome are of importance for the management of lower respiratory tract infection (LRTI). As antibiotic therapy is indicated in pneumonia and not in acute bronchitis, a predictor of pneumonia is needed. To describe the aetiology and outcome of LRTI in adults with pneumonic and adults with non-pneumonic LRTI treated in general practice and to identify predictors of radiographic pneumonia. Prospective, observational study. Forty-two general practices and an outpatient clinic at the Department of Infectious Diseases, Odense University Hospital, Denmark. A total of 364 adults diagnosed with community-acquired LRTI by their GP were studied with chest radiography, vital signs, biochemical markers of inflammation (C-reactive protein [CRP] and leukocyte count), and microbiological examinations. Primary outcome measure was hospitalisation within 4 weeks. Pneumonia was radiographically verified in 48 of 364 patients (13%). Bacterial infection was seen more often in patients with pneumonia (33% versus 17%, P