Metformin Use Correlates with Reduced Risk of Gallstones in Diabetic Patients: A 12-Year Follow-up Study

Objective: Few studies are available on the association between gallstones and metformin use. The objective of the study was to determine whether metformin use is associated with gallstones. Methods: A population-based retrospective cohort study was conducted using the database of the Taiwan National Health Insurance Program. Subjects of newly diagnosed diabetes mellitus were included from 2002 to 2013. The metformin-exposure group was defined as ≥ 29 cumulative defined daily dose (DDD) of metformin use. The unexposure group was defined as 180 cumulative DDD, compared with the unexposure group. Conclusions: Long-term use of metformin is associated with reduced risk of gallstones.