Abstract: Objective To explore the effect of polypharmacy on the long-term prognosis of elderly patients with coronary heart disease and atrial fibrillation. Methods Patients aged over 65 years with coronary heart disease and atrial fibrillation were studied and followed up for a minimum of 5 years via the telephone, outpatient and inpatient case inquiry. The difference in liver and kidney function,adverse drug reactions (ADR) and major adverse cardiovascular and cerebrovascular events (MACCE) in patients using different types of drugs was studied. Results A total of 295 patients were included in the study, with an average age of （79.2±5.9） years. In addition, 141 (47.8%) of these patients were over 80 years old. Each of them was afflicted with (6.5±1.9) kinds of diseases and used (8.3±3.2) types of dispensed drugs on average. 267 of these patients (90.5%) were treated with more than 5 types of dispensed drugs, 223 (75.6%) with antiplatelet therapy and 63 (21.4%) with anticoagulation. In different age groups, patients were divided into polypharmacy group A (dispensed drugs≥8) and polypharmacy group B (dispensed drugs<8) according to the types of medication. In the younger group（aged<80 years）, the proportion of old myocardial infarction and heart failure in group A was higher than that in group B (36.0% vs 21.5%, 52.0% vs 31.6%, respectively, P<0.05). In the older group（aged≥80 years）, NYHA heart function grade in group A was worse than that of group B (2.2±0.9 vs 2.1±1.0, P<0.05). During the follow-up of at least 5 years, the incidence of MACCE and heart failure in group A was significantly higher than that in group B in both age groups (P<0.05), and the incidence of bleeding was slightly higher in group A (P> 0.05), but there was no significant difference between the two groups in the changes of ALT, AST, GFR, ADR or death rate (P>0.05). Conclusion Polypharmacy is not uncommon in elderly patients with coronary heart disease and atrial fibrillation, especially in patients with old myocardial infarction and heart failure. During the follow-up, no deterioration of liver and kidney function, ADR or increased mortality have been found except for the slightly higher risk of bleeding. Therefore, the diagnosis and treatment of this cardiovascular high-risk population requires a comprehensive and optimized drug treatment scheme that can be simplified as long as the curative effect can be ensured to achieve the best possible prognosis

Key words: elderly, multi-morbidity, polypharmacy, coronary heart disease, atrial fibrillation, adverse cardiovascular and cerebrovascular events