Association of Sequential Organ Failure Assessment (SOFA) components with mortality

Abstract Background Sequential Organ Failure Assessment (SOFA) is a practical and widely used method to describe and quantify the presence and severity of organ system dysfunctions and failures. Some proposals suggest that SOFA could be employed as an endpoint in interventional trials. To justify this, all SOFA components should have comparable weights as organ dysfunction measures. In this study we aimed to investigate whether the associations of different SOFA components with in-hospital mortality are comparable. Methods We performed a study based on nationwide register data on adult patients admitted to 26 Finnish intensive care units (ICUs) during 2012−2015. We determined the SOFA score as the maximum score in the first 24 hours after ICU admission. We defined organ failure as an organ-specific SOFA score of three or higher. We evaluated the association of different SOFA component scores with mortality using multivariable logistic regression analysis. Results Our study population comprised 63,756 ICU patients. Overall hospital mortality was 10.7%. In-hospital mortality was 22.5% for patients with respiratory failure, 34.8% for those with coagulation failure, 40.1% for those with hepatic failure, 14.9% for those with cardiovascular failure, 26.9% for those with neurologic failure and 34.6% for the patients with renal failure. The age-adjusted odds ratio for in-hospital death was 2.41 95% confidence interval (CI) 2.27-2.56 for respiratory failure, 4.04 (95% CI 3.57-4.57) for coagulation failure, 4.24 (95% CI 3.47-5.17), for hepatic failure, 1.57 (95% CI 1.47-1.67) for cardiovascular failure, 5.00 (95% CI 4.71-5.30) for neurologic failure, and 4.93 (95% CI 4.58-5.32) for renal failure. Organ failure combinations including cardiovascular failure were associated with lower mortality than other organ failure combinations. Conclusions All SOFA components are associated with mortality, but their weights are not comparable. High cardiovascular SOFA scores do not imply an equally high risk as high scores of other components.