Simplification of the IDSA/ATS criteria for severe community acquired pneumonia using meta-analysis and observational data

Abstract

The 2007 IDSA/ATS guidelines proposed "minor" criteria to predict ICU admission in patients with community-acquired pneumonia. These criteria were based on expert opinion. Consequently the guidelines authors asked investigators to determine whether the score could be simplified by excluding non-contributory variables.

Each IDSA/ATS minor criteria were validated using a random effects meta-analysis of 7 studies. Variables present in <5% of cases or that were non-significantly associated with mortality/ICU admission were excluded. A simplified score excluding these variables was tested for prediction of mortality and ICU admission in an established database. Prediction was assessed using the area under the receiver operator characteristic curve (AUC).

Leukopaenia (<4000 cells·mm⁻³), thrombocytopenia (<100,000 cells·mm⁻³) and hypothermia <36°C occurred in <5% of cases. A simplified score excluding these variables performed similarly for prediction of mortality AUC 0.77 95%CI 0.73–0.81 vs 0.78 (0.74–0.82),p=0.9 and ICU admission AUC 0.85 (0.82–0.87) vs 0.85 (0.82–0.88),p=0.9. Additional predictors suggested by the IDSA/ATS were associated with mortality and ICU admission, but only incorporating acidosis <7.35 altered the AUC (0.82 95% CI 0.78–0.86,p=0.6 for mortality and 0.86 95% CI 0.82–0.88,p=0.8 for ICU admission). No improvements were statistically significant.

The IDSA/ATS criteria can be simplified by removing 3 infrequent variables.