Response to: 'The effect of cholecystectomy on the risk of acute myocardial infarction in patients with gallbladder stones'

Objectives: To investigate the effect of cholecystectomy on the subsequent risk of acute myocardial infarction (AMI) in patients with gallbladder stones (GBS). Methods: We used the Taiwan National Health Insurance Research Database (NHIRD) for hospitalization to conduct a retrospective nationwide population-based cohort study. The study cohort consisted of a total of 122,421 patients aged >= 20 years with cholecystectomy for GBS between 2000 and 2010. The control cohort consisted of the GBS patients without cholecystectomy and they were randomly selected by propensity score matching with the study cohort at a 1:1 ratio according to age, sex, occupation category, urbanization level, comorbidities, and year of the index date for cholecystectomy. We measured the incidence of AMI for both cohorts. Results: The cumulative incidence of AMI was lower in GB patients with cholecystectomy than that in those without cholecystectomy (2.26 vs 3.28 per 1000 person-years, adjusted hazard ratio [aHR] = 0.65, 95% confidence interval [CI] = 0.61-0.69). Compared to those without cholecystectomy, the risk of developing AMI after cholecystectomy was 0.69 (95% CI = 0.63-0.76) for the first year, 0.69 (95% CI = 0.63-0.77) for 2-5 years, and 0.59 (95% CI = 0.53-0.66) for >= 5 years, respectively. Conclusions: Our findings indicate cholecystectomy ameliorates the risk of AMI in patients with GBS, and the protective effect tends to increase with incremental duration of follow-up. However, it needs more studies to ascertain the protective mechanisms of cholecystectomy against AMI.