Can the SOAR Scoring System Predict Mortality and Hospital Readmission in Moderate and High Risk Community Acquired Pneumonia? A Prospective Validation Study

Abstract

ABSTRACT BACKGROUND Moderate to severe community acquired pneumonia (CAP) is a leading cause of mortality in the country today. Monitoring this risk group of patients requires a structured but accurate method of prognosticating adverse outcomes. OBJECTIVE To determine the validity and accuracy of the systolic BP, oxygenation, age and respiratory rate (SOAR) scoring system in predicting 30-day all cause mortality and hospital re-admission in moderate to high risk CAP. DESIGN & SETTING: Prospective validation study, Tertiary Medical Center PATIENTS AND METHODS: A total of 119 admitted adult patients with moderate to severe CAP as defined by the recent local guidelines prospectively evaluated using the SOAR index. We excluded, those who acquired pneumonia after hospital admission; hospitalization in the last 90 days; chemotherapy, long term corticosteroid therapy, HIV infection; pneumonia as an expected terminal event of a chronic disabling co-morbidity; a request from health-care proxy or prior advance directives limiting care to comfort measures; and an alternative diagnosis evolving during follow-up. Systolic BP of < 90 mmHg, O2 saturation of <95% by digital oximetry, age of 65 and respiratory rate of 30 per minute composed the criteria and was applied to this set of patients. Sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, area under the curve (AUC) were calculated together with their 95% confidence intervals. RESULTS: The mortality rate in high risk CAP was 29%, none for the moderate risk group. The SOAR criteria predicted 30-day all-cause mortality with an overall accuracy of 88.6% (Area Under the Curve, 95% CI 92-95.2, Std Error=.034, p < 90 mmHg Sn=88.2, Sp=87.2; Respiratory rate of 30 Sn=88.2, Sp=67.5). The scoring system showed fair accuracy (68.4%) in predicting hospital readmission. (Area Under the Curve, 95% CI 52-85, Std Error=.084, p=.28) CONCLUSION: The SOAR is a simple and rapid tool of prognosticating moderate to high risk community acquired pneumonia. It can be utilized without invasive laboratory tests and can be performed by trained health care personnel.