Prognostic analysis and predictive rule for outcome of hospital-treated community-acquired pneumonia

In community-acquired pneumonia (CAP) mortality may be reduced by early identification of patients requiring intensive care treatment. The purpose of this study was to determine prognostic factors of outcome in patients with CAP in order to establish a clinically applicable discriminant rule. Ninety three episodes of CAP in 92 patients were retrospectively reviewed with regard to epidemiological, clinical, laboratory and microbiological data. The prognostic analysis included a univariate as well as a multivariate approach, in order to identify parameters associated with death using the Cox regression hazard function in a backward stepwise selection model. The three parameters found to contribute most to the significance of the model were used in a discriminant rule for classification of outcome. The parameters found to be significantly different between survivors and non-survivors were heart rate, systolic and diastolic as well as mean blood pressures, leucocyte count, percentage of lymphocytes, and lactate dehydrogenase (LDH) values. The multivariate analysis revealed that heart rate, systolic arterial pressure, and LDH serum levels were most closely associated with fatal outcome. A prognostic rule composed of the variables heart rate > or = 90 beats.min-1, systolic arterial blood pressure < or = 80 mmHg, and LDH > or = 260 U.l-1 achieved a sensitivity of 77%, a specificity of 75%, and positive and negative predictive values of 42 and 93%, respectively. It was associated with a six fold increased risk of fatal outcome. In conclusion, heart rate, systolic blood pressure, and LDH values were most closely associated with death in a multivariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)