Chest radiography and pneumonia in primary care: diagnostic yield and consequences for patient management.

The current prospective cohort study assessed the diagnostic yield of chest radiography (CXR) in primary-care patients suspected of pneumonia. In total, 192 patients with a clinical suspicion of pneumonia aged >/=18 yrs were referred by their general practitioner (GP) for CXR to one of the three participating hospitals in the Netherlands. All GPs were asked to complete a standardised form before and after CXR. Pneumonia was diagnosed by GPs in 35 (18%) patients, of whom 27 (14%) patients had a positive CXR, and eight (4%) patients a negative CXR, but with an assumed high probability of pneumonia by the GP. CXR clearly influenced the diagnosis of pneumonia by the GP in 53% of the patients. CXR ruled out pneumonia in 47% and the probability of pneumonia substantially increased in 6% of the patients. Patient management changed after CXR in 69% of the patients, mainly caused by a reduction in medication prescription (from 43 to 17%) and more frequent reassurance of the patient (from 8 to 35%). In conclusion, pneumonia was frequently over diagnosed clinically by general practitioners. Chest radiography is a valuable diagnostic tool to substantially reduce the number of patients misdiagnosed and is particularly important for the exclusion of pneumonia in general practice.