Variation in SOFA (Sequential Organ Failure Assessment) Score Performance in Different Infectious States

Abstract

In this study, we investigated whether the Sequential Organ Failure Assessment (SOFA) score performance differs based on the type of infection among patients admitted to the intensive care unit (ICU) with infection. Single-center, retrospective study of adult ICU patients admitted with infection between January 2008 and April 2018 at an urban tertiary care center. Patients were uniquely classified into different infection types based on International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 codes. Infection types included were pneumonia, meningitis, bacteremia, cellulitis, cholangitis/cholecystitis, intestinal and diarrheal disease, endocarditis, urinary tract infection (UTI), and peritonitis. The SOFA score performance and mortality in relation to SOFA score were compared across infection types. A total of 12 283 patients were included. Of these, 50.6% were female and the median age was 70 years (interquartile range: 57-82). The most common infection types were pneumonia (32.2%) and UTI (31.0%). Overall, 1703 (13.9%) patients died prior to hospital discharge. The median baseline SOFA score (within 24 hours of ICU admission) for the cohort was 5 (3-8). Patients with peritonitis had the highest median SOFA score, 7 (4-9), and patients with cellulitis and UTI had the lowest median SOFA score, 4 (2-7). The SOFA score discrimination to predict mortality was highest among patients with endocarditis (area under the receiver operating characteristic [AUC]: 0.79, 95% CI: 0.69-0.90) and lowest for patients with isolated bacteremia (AUC: 0.59, 95% CI: 0.49-0.70). Observed mortality by quartile of SOFA score differed substantially across infection types. Type of infection is an important consideration when interpreting the SOFA score. This is relevant as SOFA emerges as an important tool in the definition and prognostication of sepsis.