Risk of nontyphoidal Salmonella infection in patients with cholecystectomy: Results from a nationwide matched cohort study in Taiwan.

BACKGROUND The current study was designed to investigate the association between cholecystectomy and the risk of nontyphoidal Salmonella (NTS) infection. METHODS We obtained claims-based data from the Taiwan National Health Insurance Research Database (NHIRD) to perform a nationwide cohort study. A propensity score (PS)-matching analysis was performed with a ratio of 1:2 in the cholecystectomy cohort and cholecystectomy-free group to reduce selection bias. Both groups were followed until NTS diagnosis, dropout from the insurance program, or the end of 2013. Cox proportional hazard regression analysis was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the risk of NTS infection between the cholecystectomy and cholecystectomy-free groups. RESULTS Our study enrolled 197444 patients who had undergone a cholecystectomy, and 394888 patients who did not receive cholecystectomy. The adjusted HR (aHR) of NTS infection was 1.34 (95% CI, 1.13-1.58; P 50, who underwent cholecystectomy had a higher risk of NTS infection than the matched controls. Follow-up of patients who underwent cholecystectomy showed they had a significantly higher risk of NTS infection for more than 6 months after the procedure. CONCLUSIONS Our study showed that cholecystectomy might be an independent risk factor for subsequent NTS infection.