Download Pharmacogenetic testing and Statin Drug Therapy

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CAT ASSIGNMENT- Pharmacogenetics and Statin Therapy
Kayla Abrahamson
NUR 568
University of Mary
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CAT Assignment
Pharmacogenetics and Statin Therapy
Date: August 3rd, 2015
Reviewer: Kayla M. Abrahamson, RN, DNP-S
Case Scenario
J.R. is a 55 year old male with newly diagnosed hyperlipidemia, with a LDL of 168. His BMI is
35 and his blood pressure is elevated at 148/88. He also has a history of elevated fasting blood
glucose. J.R.’s family history is positive for cardiovascular disease, and his father died from a
MI at age 64. His healthcare provider has recommended he start statin drug therapy to treat his
hyperlipidemia. He is reluctant to start statin therapy because of hearing of the potential side
effects of the drug and has heard that some patients are “resistant” to statin drug treatment. He
asks you about the local hospital’s new pharmacogenetic testing program and if this is something
he should consider prior to starting statin drug therapy.
Background
Statin therapy is recommended by multiple guidelines for treatment of hyperlipidemia. Many
prescriptions are written for statin drugs by healthcare providers in the United States, but
adherence to these medications is often poor (Charland et al., 2014). Several factors affect statin
efficacy and studies have shown that genetic interactions have some effect on statin response
(van der Baan et al., 2013). Pharmacogenetics is the study of genetic variations that influence
individual response to drugs and can be utilized to help improve patient adherence to statin drug
therapy (Charland et al., 2014).
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PICO Question
For patients with hyperlipidemia, how will the utilization of pharmacogenetic testing improve
statin drug adherence when compared to patients with hyperlipidemia on statin therapy who do
not have pharmacogenetic testing performed?
Article 1 Summary
In a study by van der Baan et al. (2013), clinical data was analyzed from the Regression
Growth Evaluation Statin Study (REGRESS). Regress is a double-blind, placebo controlled,
multicenter study assessing the effect of 2-year pravastatin treatment on the progression and
regression of coronary atherosclerosis, making this a level II source of evidence. This study
utilized a total of 884 male subjects with coronary artery disease who were randomized to either
pravastatin (40 mg) or placebo. The goal of the data analysis was to investigate whether some of
the known genetic factors, both as single-nucleotide polymorphisms (SNPs) and as gene-gene
interactions, have added value over non-genetic factors in predicting statin response. Their study
found that the 5 selected polymorphisms and the 13 corresponding gene-gene interactions have
small added value in predicting LDL-c change as response to statins over non-genetic predictors,
and also in predicting LDL-c non-treated patients. It was also determined that gene-gene
interactions had the greatest influence on the variance of statin efficacy. This study helps to
support the hypothesis that genetic influences affect statin drug treatment.
Strengths of this study are the large population analysis (884 male subjects), and use of a
randomized controlled trial design. Weaknesses are the lack of evaluating the female gender and
the lack of evaluating other confounding factors contributing to statin tolerance such as the
influence of environment and lifestyle.
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Article 2 Summary
Charland et al., (2014), utilized a prospective, non-randomized controlled trial, with a
quasi-experimental study design in their Additional KIF6 Risk Offers Better Adherence to
Statins (AKROBATS) study to evaluate the effect of personalized KIF6-testing process that used
a direct-to-patient result reporting on adherence and persistence to statin therapy at 6 months.
KIF6 carriers who take a statin drug have greater reduction in heart attack risk than other people
have. Their study found that adjusted 6-month statin adherence was significantly greater in
tested patients: 0.77 (95% confidence interval (CI) 0.72-0.82) versus controls 0.68 (95% CI
adjusted 0.63-0.73), P= 0001. Significantly more patients who were tested were adherent (63.4%
vs. 45.0%) and persisted on therapy (69.1% vs. 53.3%).
This study is a level III source of evidence, due to its non-randomized controlled design.
Strengths of this study are its large population of study (668 participants), its analysis of both
genders, and the influence of environmental, medical, and lifestyle factors on statin drug
efficacy. A weakness of the study is its rather short period of analysis (6 months) and its
observational design and lack of randomization, which may contribute to risk of confounding
results due to unmeasured variables.
Clinical Bottom Line
The analyzed studies demonstrate the potential for genetic testing to improve patient
adherence to statin therapy. Both studies were of high quality evidence and validity as
demonstrated by their large population samples and study designs. More studies should be
completed to determine if pharmacogenetic testing is a cost-effective method to improve patient
compliance and its application to the management and monitoring of statin drug efficacy in the
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treatment of coronary atherosclerosis. Both studies are relevant to today’s emerging healthcare
techniques and the expanding role of genetics in guidance of healthcare practice.
References
van der Baan, F. H., Knol, M. J., Maitland-van der Zee, A.H., Regieli, J. J., van Iperen, E. P.,
…., & Jukema, J. W. (2013). Added value of pharmacogenetic testing in predicting statin
response: Results from the REGRESS trial. The Pharmacogenomics Journal, 13, 318324. doi:10.1038/tpj.2012.12
Charland, S. L., Agatep, B. C., Herrera, V., Schrader, B., Ryvkin, M.,…., & Stanek, E. J. (2014).
Providing patients with pharmacogenetic test results affects adherence to statin therapy:
Results of the Additional KIF6 Risk Offers Better Adherence To Statins (AKROBATS)
trial. The Pharmacogenomics Journal (2014), 14, 272-280. doi:10.1038./tpj.2013.27