Evidence-based prediction of statin use with lipid-panel data from the National Health and Nutrition Examination Survey

SLCO1B1 Polymorphisms and Statin-Induced Myopathy

Statin drugs are highly effective in lowering blood concentrations of LDL-cholesterol, with concomitant reduction in risk of major cardiovascular events. Although statins are generally regarded as safe and well-tolerated, some users develop muscle symptoms that are mostly mild but in rare cases can lead to life-threatening rhabdomyolysis. The SEARCH genome-wide association study, which has been independently replicated, found a significant association between the rs4149056 (c.521T>C) single-nucleotide polymorphism (SNP) in the SLCO1B1 gene, and myopathy in individuals taking 80 mg simvastatin per day, with an odds ratio of 4.5 per rs4149056 C allele. The purpose of this paper is to assemble evidence relating to the analytical validity, clinical validity and clinical utility of using SLCO1B1 rs4149056 genotyping to inform choice and dose of statin treatment, with the aim of minimising statin-induced myopathy and increasing adherence to therapy. Genotyping assays for the rs4149056 SNP appear to be robust and accurate, though direct evidence for the performance of array-based platforms in genotyping individual SNPs was not found. Using data from the SEARCH study, calculated values for the clinical sensitivity, specificity, positive- and negative-predictive values of a test for the C allele to predict definite or incipient myopathy during 5 years of 80 mg/day simvastatin use were 70.4%, 73.7%, 4.1% and 99.4% respectively. There is a need for studies comparing the clinical validity of SLCO1B1 rs4149056 genotyping with risk scores for myopathy based on other factors such as racial background, statin type and dose, gender, body mass index, co-medications and co-morbidities. No direct evidence was found for clinical utility of statin prescription guided by SLCO1B1 genotype.

Impact of lipid-lowering medications and low-density lipoprotein levels on 1-year clinical outcomes after coronary artery bypass grafting

BACKGROUND

Studies investigating lipid-lowering medication (LLM) use and LDL levels in coronary artery bypass grafting patients are limited.

STUDY DESIGN

The Veterans Affairs Randomized On/Off Bypass Trial's patient records were analyzed for LLM use and 1-year LDL levels. Mortality, acute MI (AMI), and repeat revascularization rates were compared at 1 year between patients with and without LLM at discharge. In addition, AMI, repeat revascularization, and graft patency were compared between patients that did and did not achieve a 1-year LDL target level of <100 mg/dL.

RESULTS

The LLM data were available for 86.4% (1,904 of 2,203) of patients. Rates of LLM use were 83.4% (1,316 of 1,577) at discharge and 90.0% (1,713 of 1,904) at 1 year. Patients discharged after coronary artery bypass grafting on LLMs had a significantly lower 1-year mortality rate (1.9% vs 5.4%; p < 0.01) than those not discharged on LLM, and 1-year AMI and repeat revascularization rates were not significantly different. Of the patients with 1-year LDL measurements, 69.4% (1,200 of 1,729) achieved an LDL target level of <100 mg/dL. No differences were seen in AMI, revascularization, or graft occlusion rates between patients who achieved target LDL levels and those who did not.

CONCLUSIONS

Rates of LLM use among veterans post-coronary artery bypass grafting are high. Discharge on LLM might be associated with improved intermediate-term survival. Patients who achieved an LDL target of <100 mg/dL at 1-year did not experience improved 1-year clinical outcomes or graft patency. Longer-term follow-up might reveal differences in cardiac outcomes related to achievement of target LDL levels.