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

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. 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. 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. 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.