Objective:To investigate the correlation between red cell volume distribution width (RDW) variation coefficient and mortality in patients with liver cirrhosis complicated with sepsis.Methods:From 2008 to 2019, the real clinical data of patients admitted to the intensive care unit (ICU) of Beth Israel Deaconess Medical Center, Massachusetts Institute of Technology were selected from the American Medical Information Mart for Intensive Care-Ⅳ (MIMIC-Ⅳ) database. Structured Query Language was used to extract the demographic information, physiological indicators, laboratory test indicators, complications, in-hospital mortality, and sequential organ failure assessment (SOFA) score from the MIMIC-Ⅳ database. Analysis of variance and Kruskal-Wallis test were used to analyze the characteristics of patients in different quartiles of RDW variation coefficient and the correlation between RDW variation coefficient and different outcomes. The clinical and prognostic variables were included in the logistic regression model and its adjustment models for analysis. Model 1 was adjusted according to age and gender, and model 2 was adjusted according to age, gender, SOFA score, bilirubin, albumin, body weight, white blood cell count, serum creatinine, serum sodium, dialysis treatment, and with congestive heart failure or not. A cubic spline regression model was used to analyze the dose-response relationship between RDW variation coefficient and in-hospital mortality, ICU mortality, mild to moderate disorders of consciousness in patients with liver cirrhosis complicated with sepsis. Trend tests were performed to analyze the interaction between the RDW variation coefficient and the variables used for stratification.Results:A total of 1 443 patients with liver cirrhosis complicated with sepsis were included, with a median age of 59.0 (52.0, 67.0) years old. Among them, 954 (66.1%) were male and 489 (33.9%) were female. The RDW variation coefficient was 3.49±2.50. Totally 382 patients died during hospitalization, 246 patients died in ICU, and 259 patients with mild to moderate disorders of consciousness. When RDW variation coefficient was analyzed as a continuous variable, the OR values (95% confidence interval (95% CI)) of unadjusted model, model 1, and model 2 in in-hospital mortality, ICU mortality and mild to moderate disorders of consciousness were 1.12 (1.09 to 1.16), 1.14 (1.10 to 1.17), 1.08 (1.03 to 1.13); 1.11 (1.07 to 1.15), 1.12 (1.08 to 1.16), 1.07 (1.02 to 1.12); and 1.16 (1.12 to 1.20), 1.16 (1.12 to 1.20), 1.12 (1.07 to 1.17); respectively. The fourth quartile of RDW variation coefficient (>4.74, 29.08) was taken as the control group, the OR values (95% CI) of the unadjusted model, model 1, and model 2 were 3.00 (2.13 to 4.25), 3.32 (2.34 to 4.74), 1.76 (1.10 to 2.84); 3.42 (2.27 to 5.26), 3.81 (2.50 to 5.90), 1.77 (1.03 to 3.11); and 8.52 (5.23 to 14.63), 8.35 (5.10 to 14.38), 5.56 (2.87 to 11.69); respectively. There was a linear correlation between RDW variation coefficient and in-hospital mortality, ICU mortality, mild and moderate disorders of consciousness (all P<0.05). Among patients with higher SOFA scores, along with the increase of RDW variation coefficient, the increase of in-hospital mortality, ICU mortality and the incidence of mild and moderate disorders of consciousness, were more significant than those of patients with lower SOFA scores ( P=0.022, 0.024, and 0.001). Conclusion:Variation coefficient of RDW is associated with increased risk of disorders of consciousness and in-hospital mortality in patients with liver cirrhosis complicated with sepsis.