[Community-acquired pneumonia requiring inpatient treatment: outcome and prognostic rule]

Mortality in community-acquired pneumonia (CAP) may be reduced by early identification of patients requiring intensive care treatment. The purpose of the study was to determine prognostic factors of outcome in patients with CAP in order to establish a clinically applicable discriminant rule.

93 episodes of 92 patients with CAP were reviewed with regard to epidemiological, clinical, laboratory and microbiologic data. The prognostic analysis included a univariate as well as a multivariate approach in order to identify parameters correlated 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, diastolic as well as mean blood pressures, leucocyte count, percentage of laymphocytes, and LDH values. The multivariate analysis revealed that heart rate, systolic arterial pressure, and LDH serum levels were associated best with lethal outcome (overall significance of the model p < 0.005). A prognostic rule composed of the variables heart rate > or = 90 beats/min, systolic arterial blood pressure < or = 80 mmHg and LDH > or = 260 U/l 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 6-fold increased risk of lethal outcome.

Heart rate, systolic blood pressure, and LDH values were associated best with death in a multivariate analysis. A discriminant rule consisting of these three variables achieved favourable classification results. The rule qualifies for further prospective validation and may prove useful in the management of hospital treated CAP.