Long-Term Low-Dose Aspirin Use Reduces Gastric Cancer Incidence: A Nationwide Cohort Study

PURPOSE: The aim of this study was to investigate whether aspirin use can reduce the incidence of gastric cancer in patients with hypertension or type 2 diabetes. MATERIALS AND METHODS: A total of 200,000 patients with hypertension or type 2 diabetes were randomly selected from the Korean National Health Insurance claim database. Of these, 3,907 patients who used 100 mg of aspirin regularly (regular aspirin users) and 7,808 patients who did not use aspirin regularly (aspirin non-users) were selected at a frequency of 1:2, matched by age, sex, comorbid illnesses (type 2 diabetes and hypertension), and observation periods. The incidence of gastric cancer in this cohort was then assessed during the observation period of 2004 to 2010. RESULTS: In the matched cohort, the incidence rates of gastric cancer were 0.8% (31/3,907) for regular aspirin users and 1.1% (86/7,808) for aspirin non-users, but the cumulative incidence rates were not significantly different between groups (p=0.116, log-rank test). However, in multivariate analysis, regular aspirin users had a reduced risk of gastric cancer (adjusted hazard ratio [aHR], 0.71; 95% confidential interval [CI], 0.47 to 1.08; p=0.107). Duration of aspirin use showed significant association with reduction of gastric cancer risk (aHR for each year of aspirin use, 0.85; 95% CI, 0.73 to 0.99; p=0.044), particularly in patients who used aspirin for more than 3 years (aHR, 0.40; 95% CI, 0.16 to 0.98; p=0.045). CONCLUSION: Long-term low-dose aspirin use was associated with reduced gastric cancer risk in patients with hypertension or type 2 diabetes.