Abstract: Objective To investigate the efficacy and safety of noval oral anticoagulants(NOACs)with reduced dose and standard dose in the elderly aged 80 years and over. Methods PubMed, Cochrane Library, Embase, CNKI, Wanfang Database, and VIP Journal database were applied to research from the establishment of the database to February 2025, and the studies that met the criteria were screened. The outcomes included stroke/systemic embolism(acute myocardial infarction, pulmonary embolism, deep venous thrombosis of lower limbs, etc.), bleeding events(intracranial hemorrhage, gastrointestinal hemorrhage and severe bleeding in other places, etc.)and all-cause death. Results A total of 10 cohort studies were included in the meta-analysis, involving a total of 45 574 patients. In terms of efficacy, there was no significant difference in the risk of embolism between the reduced dose group and the standard dose group(RR=1.40, 95%CI=0.99-1.99, P=0.06). However, sensitivity analysis showed that the reduced dose group was associated with an increased risk of embolism after excluding studies with high heterogeneity. The difference was statistically significant(RR=1.67, 95%CI=1.42-1.97, P<0.05). In terms of safety, there was no significant difference in the risk of bleeding between the reduced dose group and the standard dose group(RR=0.90, 95%CI=0.73-1.11, P=0.33), but there was a higher risk of all-cause death(RR=1.49, 95%CI=1.18-1.89, P<0.05). Conclusion This study shows that for the elderly aged 80 years and over, the use of reduced doses of NOACs may be associated with higher risks of embolism and all-cause death, but there is no significant difference in the risk of bleeding. After excluding renal insufficiency, low body weight and combined use of antiplatelet drugs, standard dose of NOACs can be considered.

Key words: elderly people, noval oral anticoagulants, dose, non-valvular atrial fibrillation, cohort study, Meta-analysis