Red blood cell distribution width predicts long-term outcomes in sepsis patients admitted to the intensive care unit

Background: Although some underpowered studies have proven that increased red blood cell distribution width (RDW) may be associated with short-term prognosis of sepsis, the long-term prognostic value of RDW remains largely unknown. Methods: This retrospective observational study was based on the Medical Information Mart for Intensive Care III (MIMIC III), a large critical care database. Baseline RDW and conventional disease severity scores were extracted along with data on 4-year mortality, of adult patients with severe sepsis upon first admission to the intensive care unit (ICU). The prognostic value of RDW was analyzed with Kapan-Meier cure, Cox model, receiver operating characteristic (ROC) curve analysis, net reclassification index (NRI) and integrated discriminatory index (IDI). Results: A total of 4264 subjects were included. The area under ROC curve of RDW for predicting 4-year mortality was 0.64 (95% CI: 0.63-0.66). In multivariable Cox model, increased RDW was independently associated with all-cause mortality, irrespective of anemia. With conventional severity scores as reference, RDW had continuous NRI comprised between 0.18 and 0.20, and IDI comprised between 0.30 and 0.40. Conclusion: RDW values significantly predicts long-term all-cause mortality in critically ill patients with severe sepsis beyond conventional severity scores.