Disease Risk and Mortality Prediction in Intensive Care Patients with Pneumonia. Australian and New Zealand Practice in Intensive Care (ANZPIC II)

Abstract

This study of ventilated patients investigated pneumonia risk factors and outcome predictors in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units within Australia and New Zealand. For community acquired pneumonia, mortality increased with immunosuppression (OR 5.32, CI 95% 1.58-1799, P<0.01), clinical signs of consolidation (OR 2.43, CI 95% 1.09-5.44, P=0.03) and Sepsis-Related Organ Failure Assessment (SOFA) scores (OR 1.19, CI 95% 1.08-1.30, P<0.001) but improved if appropriate antibiotic changes were made within three days of intensive care unit admission (OR 0.42, CI 95% 0.20-0.86, P=0.02). For hospital-acquired pneumonia, immunosuppression (OR 6.98, CI 95% 1.16-42.2, P=0.03) and non-metastatic cancer (OR 3.78, CI 95% 1.20-11.93, P=0.02) were the principal mortality predictors. Alcoholism (OR 7.80, CI 95% 1.20-17.50, P<0.001), high SOFA scores (OR 1.44, CI 95% 1.20-1.75, P=0.001) and the isolation of "high risk" organisms including Pseudomonas aeruginosa, Acinetobacter spp, Stenotrophomonas spp and methicillin resistant Staphylococcus aureus (OR 4.79, CI 95% 1.43-16.03, P=0.01), were associated with increased mortality in ventilator-associated pneumonia. The use of non-invasive ventilation was independently protective against mortality for patients with community-acquired and hospital-acquired pneumonia (OR 0.35, CI 95% 0.18-0.68, P=0.002). Mortality was similar for patients requiring both invasive and non-invasive ventilation and non-invasive ventilation alone (21% compared with 20% respectively, P=0.56). Pneumonia risks and mortality predictors in Australian and New Zealand ICUs vary with pneumonia type. A history of alcoholism is a major risk factor for mortality in ventilator-associated pneumonia, greater in magnitude than the mortality effect of immunosuppression in hospital-acquired pneumonia or community-acquired pneumonia. Non-invasive ventilation is associated with reduced ICU mortality. Clinical signs of consolidation worsen, while rationalising antibiotic therapy within three days of ICU admission improves mortality for community-acquired pneumonia patients.