Objective The Japanese Respiratory Society (JRS) last revised the guidelines for community-acquired pneumonia (CAP) in adults in 2005. These guidelines proposed new criteria (A-DROP) to assess the severity of pneumonia and to differentiate between typical bacterial pneumonia and atypical pneumonia. The goal of the present study was to evaluate the utility of the A-DROP criteria for these described purposes.
Methods An observational survey was conducted between July 2006 and March 2007, and patients with CAP were prospectively surveyed using consecutive enrollment methods.
Patients In total, 1,875 patients from 200 medical facilities throughout Japan were analyzed.
Results The JRS 2005 A-DROP system was a good indicator of mortality in the patient population, and these results were significantly correlated with the Pneumonia Severity Index (PSI) of the Infectious Disease Society of America (IDSA). Among the various factors characterized, 'SpO₂ of 90% or less (PaO₂ of 60 Torr or less)' was the strongest predictor of mortality. In terms of the differential diagnosis between typical bacterial and atypical pneumonia, five of six JRS 2005 items were strongly and significantly correlated with a diagnosis of atypical pneumonia.
Conclusion The JRS 2005 A-DROP system was accurate and clinically useful for the assessment of the severity of pneumonia and for the differentiation between typical bacterial pneumonia and atypical pneumonia.