Fibrinogen Is Associated with Prognosis of Critically Ill Patients with Sepsis: A Study Based on Cox Regression and Propensity Score Matching

Abstract

Introduction. Sepsis is a common syndrome in critically ill patients. Fibrinogen was reported to be associated with the prognosis of sepsis patients. Materials and Methods. Data was acquired from Multiparameter Intelligent Monitoring in Intensive Care Database IV (MIMIC-IV) version 1.0. Cox proportional hazards regression was utilized to estimate the relationship between fibrinogen and inhospital mortality. The cumulative incidence of mortality by fibrinogen level was estimated through the Kaplan-Meier curve. Restricted cubic spline (RCS) was used to assess nonlinear relationship. Subgroup analysis was also conducted to evaluate the robustness of the association between fibrinogen and inhospital mortality. Propensity score matching (PSM) was applied to adjust for confounding factors. Results. A total of 3365 patients, including 2031 survivors and 1334 nonsurvivors, were enrolled in our study. The survivors had a significantly elevated levels of fibrinogen compared with the deceased. The elevated level of fibrinogen was significantly associated with a decrease in mortality in multivariate Cox regression before and after PSM (HR 0.66, $P<0.001$ and HR 0.73, $P<0.001$ , respectively). RCS showed a nearly linear relationship. Subgroup analysis demonstrated the robustness of the association in most subpopulations. However, the association between decreased levels of fibrinogen and increased inhospital mortality was denied after PSM. Conclusion. The elevated level of fibrinogen hints at better overall survival in critically ill patients with sepsis. Decreased levels of fibrinogen may be of little value in identifying patients with a high risk of death.