Adherence to changing from brand-name to generic atorvastatin in newly treated patients: a retrospective cohort study using health insurance claims.

Background Effect of statin therapy has been reported to be associated with patient’s adherence. Atorvastatin was available in Japan as a brand-name product beginning in 2000. The first atorvastatin generics were introduced in Japan in November 2011. The objective of this study was to analyze whether changing from a brand-name atorvastatin to a generic product would affect patient adherence.