The purpose of this study was to investigate the clinical aspects of patients satisfying the Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) minor severity criteria, focusing on their treatment response to empirical antibiotics. In total, 381 community-acquired pneumonia (CAP) patients who did not require mechanical ventilation or vasopressors at admission were enrolled, and 50 (13.1%) satisfied the minor severity criteria (i.e. , minor severe CAP [minor-SCAP]). The rates of new complication events and clinical treatment failure were significantly higher in the minor-SCAP group than in the control group (30.0% vs 2.1%, P < 0.001, and 42.0% vs 10.6%, P < 0.001, respectively), and the time to reach clinical stability was longer in the minor-SCAP group (8 days vs 3 days, P < 0.001). In a multivariate model, minor severity criteria (≥ 3) were significantly associated with treatment failure (odds ratio, 2.838; 95% confidence interval, 1.216 to 6.626), and for predicting treatment failure the value of the area under the receiver operating characteristic curve for minor criteria was 0.731, similar to other established scoring methods. The IDSA/ATS minor severity criteria can predict delayed treatment response and clinical treatment failure.
Keywords: Minor Criteria; Pneumonia; Severe; Treatment Response.