Statin Discontinuation Related to Antihypertensive Medication Adherence

SAN FRANCISCO, CA—Huifeng Yun, PhD, and colleagues from the University of Alabama at Birmingham, in Birmingham, AL presented data stating that low adherence to antihypertensive medication may be useful in identifying patients likely to discontinue statins within one year of initiation at ACC.13, the American College of Cardiology's 62nd Annual Scientific Session.

Researchers utilized a retrospective cohort study to determine if there was a correlation between the level of adherence to antihypertensive medication prior to initiating statin therapy and statin discontinuation.  Patients were randomly chosen from a 5% sample of Medicare beneficiaries enrolled in a traditional fee-for-service Medicare program with prescription drug coverage in 2007.  A total of 25,308 new statin users were included, of which 18,434 (72.8%) took antihypertensives during the baseline period.

Newly prescribed statin patients was defined as filling ≥1 statin prescription in 2007 without a statin prescription in the previous 365 days (the “baseline” period). Statin discontinuation was defined as failure to renew statin prescription within one year of initiating treatment and no subsequent fills for 365 days. Medication possession ratio (MPR) was defined as the total number of days supply during the baseline period, divided by the total number of days between the first fill date and the end of baseline period. In patients taking more than one class of antihypertensive medications, a weighted average of class-specific MPRs was used.

In the population taking antihypertensive medications, 61.2%, 25.8% and 13% had a medication possession ratio of ≥80%, 50–80% and <50%, respectively.  A lower adherence to antihypertensive medications was associated with an increased hazard ratio for statin discontinuation. The percentage of patients discontinuing statins within one year was 19.6%, 23.5% (HR 1.21, CI 1.13–1.30), and 26.3% (HR 1.38, CI1.26–1.51) in users with a MPR of ≥80%, 50–80% and <50%, respectively.

Dr. Yun commented, “There is a need for adherence strategies directed at multiple classes of preventative therapies.” Patients not adherent to one drug class might be more likely to discontinue a newly prescribed medication. It may be useful to identify patients with low adherence to antihypertensive medications to determine patients who may discontinue statins within one year of initiation.