The Japanese Respiratory Society guidelines may reduce unnecessary chest computed tomography in patients with pneumonia requiring hospitalization: A retrospective study

With the abundance of CT scanners in Japan, doctors can easily order CT scans to diagnose pneumonia. The Japanese Respiratory Society (JRS) guidelines uniquely recommend conditions for which additional CT scans should be considered at the time of diagnosis of pneumonia, a feature not found in other guidelines. In this study, we aimed to evaluate the usefulness of the recommendations in a bid to reduce the number of unnecessary CT examinations. We retrospectively reviewed the electronic medical records of consecutive patients with pneumonia hospitalized between April 2016 and March 2017 to extract patients’ backgrounds and clinical courses. Conformity with the JRS guideline recommendations was also examined. In the patients who did not meet the recommendations, we investigated the proportion of them for whom an additional CT scan influenced the clinical decisions. Finally, we evaluated whether there was a difference in hospital stay depending on the additional chest CT at the time of admission. We included 363 hospitalized patients with pneumonia. Chest CT scan was performed in 306 patients (84.3%), of whom 186 (60.8%) did not meet the JRS guideline recommendations. Chest CT revealed findings requiring a change in treatment strategy in only 14 (7.5%) of the 186 patients. Among the 240 patients (66.1%) who did not meet the recommendations, no statistically significant difference was observed in the hospital stay or mortality between patients with and without CT scans. Adherence to the JRS guideline recommendations may reduce the excessive use of CT scans in the diagnosis of pneumonia.