Abstract:ObjectiveTo evaluate the predictive value of vitamin D in patients with heart failure with reduced ejection fraction (HFrEF). Methods A restrospective study was conducted on 111 patients with HFrEF in Nanjing Drum Tower Hospital from July 2017 to February 2018. The patients were divided into three groups according to the serum 25-(OH)D ₃ levels: deficient group ［25-(OH)D ₃＜12 ng/ml, n=18］, inadequate group ［25-(OH)D ₃ 12-20 ng/ml, n=45］ and adequate group ［25-(OH)D ₃ ＞20-50 ng/ml, n=48］. Clinical outcomes of patients within 24 months after discharge ware obtained by outpatient department or telephone follow-up. Kaplan-Meier curve was used to evaluate the incidence of major adverse cardio-cerebrovascular event(MACE). The independent predictive factors were identified by Cox proportional hazards regression model. Results During the follow-up period, the incidences of deterioration rate of heart failure in MACE were 38.9%, 15.6%, and 12.5% in vitamin D deficiency group, inadequate group and adequate group, respectively, and the vitamin D deficiency group was the highest (P<0.05); with the progression of the disease, the cumulative incidence of MACE in the vitamin D deficiency group was significantly increased (P=0.038). Older age, hypertension, diabetes, ischemic cardiomyopathy and 25-(OH)D ₃＜12 ng/ml were independent risk factors for the increased incidence of MACE in HFrEF patients (P＜0.05). Conclusion Serum 25-(OH)D ₃＜12 ng/ml is associated with a significant increase in the incidence of MACE in patients with HFrEF.