Sex differences in the association between red cell distribution width and 30-day mortality in critically ill patients with acute cholangitis: a retrospective cohort study.

PURPOSE: Acute cholangitis (AC) is an emergency disease with a high risk of mortality. Red cell distribution width (RDW) has been proven to correlate with the adverse outcomes of several clinical conditions. The present study aims to investigate the association between RDW and 30-day mortality in critical AC.

METHODS

This retrospective cohort study collected patients with AC from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Patients were divided into tertiles according to baseline RDW values. We performed multivariable Cox regression and Kaplan-Meier survival analysis to evaluate the association between RDW and 30-day mortality. The predictive performance of RDW was assessed by the receiver operating characteristic (ROC) curve, along with integrated discrimination improvement (IDI) analysis. Subgroup analyses were employed to explore the interactions between selected covariates in RDW-mortality associations. Lastly, sex-stratified restricted cubic spline (RCS) was depicted to verify the sex-specific differences.

RESULTS

Out of 756 patients, 146 cases experienced death within 30 days. Fully multivariable Cox regression analysis demonstrated elevated RDW levels were positively associated with an increased risk of 30-day mortality (adjusted hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.01-1.15). The mortality risk followed an equidistantly gradual increase according to RDW tertiles (P for trend = 0.027). Kaplan-Meier survival analysis also displayed mortality disparities (log-rank test: P < 0.001). ROC analysis indicated that RDW exhibited an AUC of 0.733. IDI analysis revealed the significant incremental predictive value of RDW for the Sequential Organ Failure Assessment score (SOFA), Charlson Comorbidity Index (CCI), and Acute Physiology Score III (APS III) (P < 0.001 for all). The association of RDW with 30-day mortality in AC was more pronounced in males (P for interaction = 0.007). The sex-stratified RCS curves also suggested a heterogeneity in the RDW-mortality association between males and females. Sensitivity analysis corroborated the sex difference in the RDW-mortality association in AC.

CONCLUSION

RDW is associated with 30-day mortality in critically ill patients with AC, and this association demonstrates a heterogeneity in different sexes, underscoring the potential prognostic values of RDW in AC.