Effectiveness of a Pneumonia Severity Index (PSI) as a Predictor of Mortality in Emergency Department Patients with Community-Acquired Pneumonia

ABSTRACT

PURPOSE: Pneumonia is the most common cause of death among infectious diseases. Community-acquired pneumonia is the sixth leading cause of death in Korea. This study was designed to analyze the relationship of risk factors and mortality, especially the pneumonia severity index (PSI) in patients with community-acquired pneumonia diagnosed in the emergency department of a referral hospital. METHODS: The medical records of patients admitted to the Yeungnam University Hospital between March 2006 and March 2008 for community-acquired pneumonia were reviewed retrospectively. The demographic data, comorbidity, laboratory results, PSI score and class of PSI, all of which might influence the prognosis of pneumonia, were analyzed. RESULTS: Among 123 patients admitted for community-acquired pneumonia, 18 died (mortality rate of 15%). Laboratory data showed that sodium, glucose, blood urea nitrogen, albumin, platelets, hematocrit and arterial pH were related to the prognosis. For the pneumonia severity index, the mortality rate increased in a step-wise manner from class I through class V. Comorbidities such as neoplasms (p=0.000), cerebrovascular accidents (p=0.005) and liver disease (p=0.003), as well as systolic blood pressure (p=0.003), respiratory rate (p=0.024), sodium (p=0.000), glucose (p=0.000), blood urea nitrogen (p=0.000), albumin (p=0.003), hematocrit (p=0.000) and arterial pH (p=0.042) were the important risk factors for mortality in patients with community-acquired pneumonia. CONCLUSION: The pneumonia severity index could be used as a valuable index for predicting mortality of patients and the prognosis of community-acquired pneumonia in the emergency department.