Discontinuation of statins in routine care settings: a cohort study.
BACKGROUND
Systematic data on discontinuation of statins in routine practice of medicine are limited.


OBJECTIVE
To investigate the reasons for statin discontinuation and the role of statin-related events (clinical events or symptoms believed to have been caused by statins) in routine care settings.


DESIGN
A retrospective cohort study.


SETTING
Practices affiliated with Brigham and Women's Hospital and Massachusetts General Hospital in Boston.


PATIENTS
Adults who received a statin prescription between 1 January 2000 and 31 December 2008.


MEASUREMENTS
Information on reasons for statin discontinuations was obtained from a combination of structured electronic medical record entries and analysis of electronic provider notes by validated software.


RESULTS
Statins were discontinued at least temporarily for 57 292 of 107 835 patients. Statin-related events were documented for 18 778 (17.4%) patients. Of these, 11 124 had statins discontinued at least temporarily; 6579 were rechallenged with a statin over the subsequent 12 months. Most patients who were rechallenged (92.2%) were still taking a statin 12 months after the statin-related event. Among the 2721 patients who were rechallenged with the same statin to which they had a statin-related event, 1295 were receiving the same statin 12 months later, and 996 of them were receiving the same or a higher dose.


LIMITATIONS
Statin discontinuations and statin-related events were assessed in practices affiliated with 2 academic medical centers. Utilization of secondary data could have led to missing or misinterpreted data. Natural-language-processing tools used to compensate for the low (30%) proportion of reasons for statin discontinuation documented in structured electronic medical record fields are not perfectly accurate.


CONCLUSION
Statin-related events are commonly reported and often lead to statin discontinuation. However, most patients who are rechallenged can tolerate statins long-term. This suggests that many of the statin-related events may have other causes, are tolerable, or may be specific to individual statins rather than the entire drug class.


PRIMARY FUNDING SOURCE
National Library of Medicine, Diabetes Action Research and Education Foundation, and Chinese National Key Program of Clinical Science.