Establishment of a Highly Predictive Survival Nomogram For Patients With Sepsis: A Retrospective Cohort Study

Abstract

Background: Sepsis is a critical illness common in intensive care units (ICUs) and emergency rooms worldwide and is associated with high morbidity and mortality. However, exisiting methods to predict mortality from sepsis, such as the Sequential Organ Failure Assessment (SOFA) score, are insufficient. This paper aimed to construct a nomogram for predicting the 30-, 60-, and 90-days mortality risks of patients with sepsis that is more accurate than the SOFA score alone. Methods: Data on sepsis patients were obtained from the Medical Information Mart for Intensive Care (MIMIC) database and analysed retrospectively. The included patients were randomly divided into a training cohort and a validation cohort. The variables included in the training cohort were selected using a backward stepwise selection method with Cox regression, which were then used to construct a prognostic nomogram. In the validation cohort, we compared our prognostic nomogram with the existing SOFA using the area under the time-dependent receiver operating characteristic curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI), calibration plotting and decision-curve analysis (DCA).Results: We included a total of 5240 patients in the study, who were divided into the training (n=3667) and validation (n=1573) cohorts. Patient age and the following clinical parameters obtained on the first day of ICU admission were included in the nomogram: SOFA score, metastatic cancer, SpO2, lactate, body temperature, albumin, and red blood cell distribution width (RDW). The AUCs for the 30-, 60-, and 90-days mortality risks were better for our nomogram than for the SOFA score, with values of 0.766, 0.771, and 0.772, respectively, in the training cohort and 0.759, 0.770, and 0.760, respectively, in the validation cohort. The nomogram also showed good calibration, as indicated by the evidence that the predicted values of the survival risks at 30-, 60-and 90-days were in good agreement with the observed values both in the training and validation sets. In addition, IDI and NRI improved over the entire follow-up period. Finally, DCA was used to verify the clinical value of the model and its impact on actual decision-making. We can see that the net benefit of the nomogram is greater than the SOFA score for any predicted probability, both in the training set and in the validation set, indicating that it has a substantial net benefit in predicting 30-, 60-, and 90-days survival rates. Conclusions: We established a nomogram that performed better than the SOFA score in predicting the prognosis of patients with sepsis. Further studies with a large sample size are needed to verify the generalizability of the nomogram.

The Clinical Utility of Albumin with Sequential Organ Failure Assessment (SOFA) in Improving 30-Day Mortality Prediction in Patients with Infection in the Emergency Department

“…In their study on post-traumatic patients with sepsis, Lu et al demonstrated that the predictive ability of a model based on clinical and biochemical markers that incorporated the albumin level (AUROC = 0.799) outperformed the SOFA score (AUROC = 0.698; p < 0.001). In another retrospective study on 5240 patients with sepsis, adding other laboratory parameters into the SOFA score improved ability to predict death in 30 days (AUROC = 0.681-0.766) [29,30]. A recent retrospective study on 725 patients with sepsis who were discharged from the hospital found that a serum albumin level of <2.5 mg/dL (odds ratio [OR] = 2.616) and a SOFA score of ≥2 (OR = 2.106) at discharge were independent prognostic factors for one-year mortality, indicating that these two variables may fit well in the prognostic assessment of patients [31].…”