Clinical Investigation
Acute Ischemic Heart Disease
Patient adherence to generic versus brand statin therapy after acute myocardial infarction: Insights from the Can Rapid Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines Registry

https://doi.org/10.1016/j.ahj.2015.04.011Get rights and content

Background

Statins reduce mortality after acute myocardial infarction, but up to half of patients discontinue statin use within 1 year of therapy initiation. Although cost may influence medication adherence, it is unknown whether use of generic versus brand statins influences adherence.

Methods and results

We linked detailed inhospital clinical data for 1421 non–ST-segment elevation myocardial infarction patients discharged on a statin in 2006 to Medicare Part D medication claims records to examine postdischarge medication use. One-year statin adherence was defined using the proportion of days covered with optimal adherence ≥80%. We examined the association of brand versus generic statin prescription and 1-year adherence after adjusting for demographics, clinical factors, predischarge lipid values, prior statin use, and socioeconomic status. Overall, 65.5% of statin fills were for brand-name statins. There were few baseline differences in demographics and clinical factors among generic versus brand users. Patient copay amounts were higher for brand versus generic statins (median = $25 vs $5, P < .001), yet the mean proportion of days covered over 1 year was similar (71.5% vs 68.9%; P = .97; unadjusted odds ratio 1.15 [95% CI 0.96-1.37]). Proportion of days covered ≥80% was low for both generic (56.2%) and brand statins (55.9%; P = .93). Statin adherence rates remained similar between generic and brand users after adjusting for demographics, clinical risk factors, lipid value, prior statin use, and socioeconomic status.

Conclusions

In a cohort of older non–ST-segment elevation myocardial infarction patients, we found no evidence that use of generic versus brand drug was associated with higher adherence to statins at 1 year after hospital discharge.

Section snippets

Data sources

We used data from the CRUSADE study, which was a national observational inpatient registry conducted from 2001 to 2006 with the goal of improving quality of care through promoting evidence-based treatment for patients with unstable angina and NSTEMI. The years during which the CRUSADE study was conducted encompass a period where both generic and brand statins were available, in addition to the period directly after publication of the PROVE IT–TIMI 22 trial, which demonstrated superiority of a

Results

Of 1,421 NSTEMI patients aged >65 years, 931 (65.5%) received brand statin therapy, whereas 490 (34.5%) received generic statin therapy. Patients who received brand statins were similar to those who received generic statins with regard to age, gender, and race (Table I). The distribution of medical comorbidities was generally similar across brand and generic statin groups. Patients who received generic statins also had similar values of high-density lipoprotein cholesterol, low-density

Discussion

We evaluated 1-year adherence rates among generic and brand name statin users in a cohort of older NSTEMI patients from a geographically diverse sample. Our major findings are as follows: (1) overall, adherence to statins at 1 year was suboptimal for all patients with >40% of patients not having optimal adherence (PDC >80%) and (2) use of a generic statin was not associated with higher 1-year adherence in either unadjusted or adjusted models.

Our results showing suboptimal adherence to statin

Limitations

Our study had several limitations. First, despite adjustment for detailed clinical and socioeconomic data, we cannot exclude the possibility of residual confounding. Second, although the PDC has been previously validated as a metric of adherence, it is a representation of prescription fills—not medication-taking behavior. Third, this study was primarily conducted before the widespread introduction of $4 generic programs, which were launched in late 2006; however, it is still possible that some

Conclusions

In a cohort of older NSTEMI patients enrolled in Medicare Part D, we found that overall adherence to statin therapy to 1 year was suboptimal, but we did not find evidence of improved adherence among patients prescribed generic versus brand statins. Future work assessing reasons for suboptimal statin adherence and associations between medication use patterns and long-term outcomes in cardiovascular disease populations is needed.

Conflict of interest disclosures

EC O'Brien: Dr O'Brien reports that she has received research funding from Merck. LM McCoy: Ms McCoy has no relevant disclosures to report. LE Thomas: Dr Thomas has no relevant disclosures to report. ED Peterson: Dr Peterson reports research funding from Eli Lilly & Company; Ortho-McNeil-Janssen Pharmaceuticals, Inc; Society of Thoracic Surgeons; American Heart Association; American College of Cardiology (all significant); consulting for AstraZeneca; Boehringer Ingelheim; Genentech; Johnson &

Acknowledgements

We thank the staff and participants of the CRUSADE Registry for their important contributions to this work.

References (32)

  • H. Hakonsen et al.

    Generic substitution: additional challenge for adherence in hypertensive patients?

    Curr Med Res Opin

    (2009)
  • B.A. Briesacher et al.

    Medication adherence and use of generic drug therapies

    Am J Manag Care

    (2009)
  • W.H. Shrank et al.

    The implications of choice: prescribing generic or preferred pharmaceuticals improves medication adherence for chronic conditions

    Arch Intern Med

    (2006)
  • N.K. Choudhry et al.

    Measuring concurrent adherence to multiple related medications

    Am J Manag Care

    (2009)
  • S. Karve et al.

    Good and poor adherence: optimal cut-point for adherence measures using administrative claims data

    Curr Med Res Opin

    (2009)
  • Area Resource File (ARF)

    Department of Health and Human Services Health Resources and Services Administration Web site

    (2007-2008)
  • Cited by (0)

    John K French, MB, PhD served as guest editor for this article.

    Sources of funding: CRUSADE was funded by Millennium Pharmaceuticals, Schering-Plough Corporation, and the Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership. This work was supported internally by the Duke Clinical Research Institute, which donated support for these analyses. The authors would like to thank Erin Hanley, MS (Duke Clinical Research Institute), for editorial assistance and article preparation. She did not receive compensation for her assistance apart from her employment at the institution where the study was conducted.

    View full text