Relationship Between the Hemoglobin-to-Red Cell Distribution Width Ratio and All-Cause Mortality in Ischemic Stroke Patients with Atrial Fibrillation: An Analysis from the MIMIC-IV Database

AIM: To investigate the association between the hemoglobin-to-red cell distribution width (RDW) ratio (HRR) and all-cause mortality in ischemic stroke patients with atrial fibrillation (AF). DESIGN: This study was a retrospective cohort analysis. In total, 1018 ischemic stroke patients with AF were enrolled using the Medical Information Mart for Intensive Care database, (MIMIC)-IV. The patients were divided into four groups according to the HRR values. The primary outcome was 180-day all-cause mortality. METHODS: Multivariate Cox proportional risk regression models were used to examine the association between HRR and all-cause mortality. The non-linear relationship between HRR and all-cause mortality was confirmed using a Cox proportional risk regression model fitted by cubic spline function and smooth curve fitting. RESULTS: A total of 246/1018 patients (24.17%) died. The serum HRR values were negatively associated with 180-day all-cause mortality (hazard ratio (HR) 0.80, 95% confidence interval (CI) 0.68–0.94). A two-piecewise regression model was used to obtain a threshold inflection point value of 9.74. The HR and the 95% CI on the left inflection point were 0.73 and 0.61–0.87 (p = 0.0005); on the right inflection point they were 1.06 and 0.82–1.38 (p = 0.6383). CONCLUSION: The relationship between all-cause mortality and the HRR values was non-linear in ischemic stroke patients with AF. All-cause mortality and HRR values were negatively correlated when the HRR value was ≤9.74.