Pneumonia severity index class v patients with community-acquired pneumonia: characteristics, outcomes, and value of severity scores

Abstract

Background: Community-acquired pneumonia (CAP) with a pneumonia severity index (PSI) score in risk class V (PSI-V) is a potentially life-threatening condition, yet the majority of patients are not admitted to the ICU. The aim of this study was to characterize CAP patients in PSI-V to determine the risk factors for ICU admission and mortality, and to assess the performance of CAP severity scores in this population.

Methods: Prospective observational study including hospitalized adults with CAP in PSI-V from 1996 to 2003. Clinical and laboratory data, microbiological findings, and outcomes were recorded. The PSI score; modified American Thoracic Society (ATS) score; the confusion, urea, respiratory rate, low BP (CURB) score, and CURB plus age of >/= 65 years score were calculated. A reduced score based on the acute illness variables contained in the PSI was also obtained.

Results: A total of 457 patients were included in the study (mean [+/- SD] age, 79 +/- 11 years), of whom 92 (20%) were admitted to the ICU. Patients in the ward were older (mean age, 82 +/- 10 vs 70 +/- 10 years, respectively) and had more comorbidities. ICU patients experienced significantly more acute organ failures. The mortality rate was higher in ICU patients, but also was high for non-ICU patients (37% vs 20%, respectively; p = 0,003). A low level of consciousness (odds ratio [OR], 3.95; 95% confidence interval [CI], 2 to 5) and shock (OR, 24.7; 95% CI, 14 to 44) were associated with a higher risk of death. The modified ATS severity rule had the best accuracy in predicting ICU admission and mortality.

Conclusions: Most CAP patients PSI-V were treated on a hospital ward. Those admitted to the ICU were younger and had findings of more acute illness. The PSI performed well as a mortality prediction tool but was less appropriate for guiding site-of-care decisions.