Prognostic value of chest computed tomography in community-acquired pneumonia patients

Abstract

Background Chest computed tomography (CT) is commonly used to diagnose pneumonia in Japan, but its usability in terms of prognostic predictability is not obvious. We modified CURB-65 (confusion, urea >7 mmol·L−1, respiratory rate ≥30 breaths·min−1, blood pressure <90 mmHg (systolic) ≤60 mmHg (diastolic), age ≥65 years) and A-DROP scores with CT information and evaluated their ability to predict mortality in community-acquired pneumonia patients. Methods This study was conducted using a prospective registry of the Adult Pneumonia Study Group – Japan. Of the 791 registry patients, 265 hospitalised patients with chest CT were evaluated. Chest CT-modified CURB-65 scores were developed with the first 30 study patients. The 30-day mortality predictability of CT-modified, chest radiography-modified and original CURB-65 scores were validated. Results In score development, infiltrates over four lobes and pleural effusion on CT added extra points to CURB-65 scores. The area under the curve for CT-modified CURB-65 scores was significantly higher than that of chest radiography-modified or original CURB-65 scores (both p<0.001). The optimal cut-off CT-modified CURB-65 score was ≥4 (positive-predictive value 80.8%; negative-predictive value 78.6%, for 30-day mortality). For sensitivity analyses, chest CT-modified A-DROP scores also demonstrated better prognostic value than did chest radiography-modified and original A-DROP scores. Poor physical status, chronic heart failure and multiple infiltration hampered chest radiography evaluation. Conclusion Chest CT modification of CURB-65 or A-DROP scores improved the prognostic predictability relative to the unmodified scores. In particular, in patients with poor physical status or chronic heart failure, CT findings have a significant advantage. Therefore, CT can be used to enhance prognosis prediction.