Prospective Observational Study Comparing Sepsis-2 and Sepsis-3 Definitions in Predicting Mortality in Critically Ill Patients

Background: Sepsis definitions have evolved, but there is a lack of consensus over adoption of the most recent definition, Sepsis-3. We sought to compare Sepsis-2 and Sepsis-3 in the classification of patients with sepsis and mortality risk at 30 days. Methods: We used the following definitions: Sepsis-2 (≥2 systemic inflammatory response syndrome criteria + infection), Sepsis-3 (prescreening by quick Sequential Organ Failure Assessment [qSOFA] of ≥2 of 3 criteria followed by the complete score change ≥2 + infection), and an amended Sepsis-3 definition, iqSOFA (qSOFA ≥2 + infection). We used χ 2 or Wilcoxon rank-sum tests, receiver-operator characteristic curves, and survival analysis. Results: We enrolled 176 patients (95% in an intensive care unit, 38.6% female, median age 61.4 years). Of 105 patients classified by Sepsis-2 as having sepsis, 80 had sepsis per Sepsis-3 or iqSOFA (kappa = 0.72; 95% confidence interval [CI], 0.62-0.82). Twenty-five (14.8%) died (20 of 100 with sepsis per Sepsis-2 [20%], and 20 of 77 [26.0%] with sepsis per Sepsis-3 or iqSOFA). Results for Sepsis-3 and iqSOFA were identical. The area under the curve of receiver-operator characteristic (ROC) curves for identifying those who died were 0.54 (95% CI, 0.41-0.68) for Sepsis-2, 0.84 (95% CI, 0.74-0.93) for Sepsis-3, and 0.69 (95% CI, 0.60-0.79) for iqSOFA (P < .01). Hazard ratios for death associated with sepsis were greatest for sepsis or septic shock per Sepsis-3. Conclusions: Sepsis-3 and iqSOFA were better at predicting death than Sepsis-2. Using the SOFA score might add little advantage compared with the simpler iqSOFA score.