Elevated red cell distribution width as a prognostic indicator in critically ill patients with atrial fibrillation and chronic kidney disease.

BACKGROUND

Red cell distribution width (RDW) has emerged as an important prognostic biomarker in various cardiovascular and renal conditions. However, its specific role in critically ill patients with coexisting atrial fibrillation (AF) and chronic kidney disease (CKD) is not well established. This study aims to evaluate the prognostic significance of RDW in this population.

METHODS

We conducted a retrospective cohort study using the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database, identifying 2208 patients with concomitant AF and CKD. We assessed the association between RDW levels and 28-day and 365-day mortality using multivariable Cox regression models, Kaplan-Meier survival analysis, receiver operating characteristic (ROC) curve and subgroup analyses.

RESULTS

Elevated RDW was independently associated with increased risks of both 28-day and 365-day all-cause mortality after multivariable adjustment (fully adjusted Hazard Ratio [HR]: 1.15 and 1.17; all p < 0.001). Patients in the highest RDW quartile demonstrated the greatest mortality risk, with an adjusted HR of 2.46 for 28-day mortality and 2.65 for 365-day mortality. Kaplan-Meier analysis revealed significantly lower survival probabilities in higher RDW quartiles (log-rank test: p < 0.001). ROC analysis demonstrated fair predictive accuracy for RDW (Area Under the Curve [AUC]: 0.64 for 28-day and 0.68 for 365-day mortality), with optimal cut-off values of 15.35% and 15.55%, respectively. Subgroup analyses confirmed the consistent prognostic value of RDW across most patient strata and identified significant interactions with CKD stage (p for interaction < 0.001) and type 2 diabetes (p for interaction = 0.048).

CONCLUSION

RDW is a valuable prognostic biomarker for identifying patients with AF and CKD who are at increased risk of both short- and long-term mortality. This supports its use in risk stratification to guide timely interventions and personalized management.

CLINICAL TRIAL NUMBER: not applicable.