Objective: This study aimed to evaluate the association between red blood cell distribution width (RDW) changes and major adverse cardiovascular event (MACE) occurrences during sacubitril/valsartan treatment in patients with heart failure with reduced ejection fraction (HFrEF).
Methods: This study retrospectively analyzed the medical records of patients with HFrEF hospitalized from April 2018 to February 2021. The patients were divided into two groups according to the inclusion of sacubitril/valsartan in the personal drug treatment regimen, the traditional and the sacubitril/valsartan group. RDW values before and after sacubitril/valsartan treatment were recorded respectively as RDW₁ and RDW₂. ΔRDW was defined as the difference between RDW₂ and RDW₁. The patients in the sacubitril/valsartan group were divided into two subgroups according to ΔRDW > 0 or ≤ 0. MACEs, such as readmission for HF, acute myocardial infarction, ischemic stroke, and malignant arrhythmia and death, were recorded during the 1-year follow-up period in each group.
Results: MACE development was lower in patients treated with sacubitril/valsartan than those treated with conventional therapy (log-rank, P< 0.001). The incidence of cardiac events during the follow-up period was greater in the group with ΔRDW > 0 than in the group with ΔRDW ≤ 0 (Breslow, P< 0.001). Increased RDW was associated with a higher likelihood of developing MACE than decreased RDW (odds ratio [OR] =2.055, 95% confidence interval [CI]:1.301– 3.246), and the risk of developing MACE increased by 22.1% for each unit increase in RDW (OR=1.221, 95% CI:1.074– 1.389).
Conclusion: Sacubitril/valsartan treatment is effective in reducing the risk of MACEs in HFrEF. Additionally, RDW changes are predictors of MACEs after sacubitril/valsartan treatment.

Keywords: red blood cell distribution width, heart failure, sacubitril/valsartan, major adverse cardiovascular events