Mortality predictors in patients with severe community-acquired pneumonia requiring ICU admission

Abstract

Abstract Background Community-acquired pneumonia (CAP) is a major cause of mortality. This prospective study was conducted to describe patient’s characteristics, mortality rate, and etiological pathogens in patients with severe CAP who required ICU admission and to determine the predictors of mortality. Patients and methods This was a multicenter prospective observational study of 57 consecutive patients who were admitted to the ICU with diagnosis of severe CAP from October 2012 to August 2015. Results Overall 57 patients were included in the study and the overall ICU mortality rate was 49.1%. Heart disease and chronic obstructive pulmonary disease were the most common comorbidities associated with severe CAP. Comparison between survivors and nonsurvivors revealed that mortality was associated with old age (P=0.01), low diastolic blood pressure (P=0.04), low PaO2/FiO2 (P=0.04), high acute physiology and chronic health evaluation II (APACHE II) score (P=0.001), (CURB-65) score (P=0.005), low hemoglobin (P=0.008), and high urea (P=0.04). The univariate analysis demonstrated that the following were the predictors of mortality: age older than 65 years (P=0.03); APACHE II score greater than 20 (P=0.007); CURB-65 of 3 or greater (0.03); total leukocyte count less than 4 or greater than 11×109/(P=0.04); PaO2/FiO2 less than 250 (P=0.03); serum urea greater than 30 mg/dl (P=0.04); presence of septic shock (P=0.003); mechanical ventilation requirement (P=0.02); and bilateral or multilobar infiltrate on chest radiograph (P=0.03). Multiple regression analysis identified high APACHE II score (>20) and septic shock as significant independent predictors of mortality in severe CAP. Microbiological identification was obtained in 52.6% of cases, with positive blood culture in 17.5%. The most frequently isolated pathogens were Streptococcus pneumonia (S. pneumonia) (19.3%) and Staphylococcus aureus (S. aureus) (15.8%). Conclusion Mortality rate in patients with severe CAP was high as reported by most of the other studies. The presence of septic shock and high APACHE II were independent predictors of mortality. Heart disease and chronic obstructive pulmonary disease were the most common comorbidities. Microbiological identification was obtained in 52.6% of cases, and S. pneumonia and S. aureus were the most frequently isolated pathogens.

Keywords

• apache II score
• curb-65 score
• ICU
• microbial etiology
• prognostic factors
• septic shock