Validation and clinical implications of the IDSA/ATS minor criteria for severe community-acquired pneumonia

Background: The 2007 Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) guidelines defined severe community-acquired pneumonia (CAP) and recommended intensive care unit (ICU) admission when patients fulfilled three out of nine minor criteria. These criteria have not been validated. Methods: All patients admitted to our hospital from 2004 to 2007 for CAP were reviewed retrospectively. Patients who fulfilled any IDSA/ATS major criteria for severe CAP at the emergency department (ie, the need for mechanical ventilation or vasopressors) were excluded. The predictive characteristics of the IDSA/ATS minor criteria were compared with those of the Pneumonia Severity Index (PSI) and the CURB-65 score for hospital mortality and ICU admission. Results: 1242 patients were studied (mean age 65.7 years, hospital mortality 14.7%). The areas under the receiver operating characteristic curves for the IDSA/ATS minor criteria were 0.88 (95% CI 0.86 to 0.91) and 0.85 (95% CI 0.81 to 0.88) for predicting hospital mortality and ICU admission, respectively. These were greater than the corresponding areas for the PSI and the CURB-65 score (p< 0.05). The sensitivity, specificity, positive and negative predictive values of the minor criteria were 81.4%, 82.9%, 45.2% and 96.3%, respectively, for hospital mortality and 58.3%, 90.6%, 52.9% and 92.3%, respectively, for ICU admission. The minor criteria were more specific than the PSI and more sensitive than the CURB-65 score for both outcomes. Conclusion: These findings support the use of the IDSA/ATS minor criteria to predict hospital mortality and guide ICU admission in inpatients with CAP who do not require emergency mechanical ventilation or vasopressors.