Statin myopathy: Incidence, risk factors, and pathophysiology

Correlates of Myopathy in Diabetic Patients Taking Statins

Diabetes is one of the most common chronic ailments; its incidence has reached epidemic proportions in the 21st century. Diabetes significantly increases micro and macrovascular complications, which are effectively managed with statins. Therefore, statins' pharmacokinetics, pharmacodynamics, and pharmacogenetics have been extensively studied. Although statins act as a keystone in preventing cardiovascular complications, at the same time, they pose a threat to the quality of life of diabetics due to the resulting muscular side effects. This article summarizes the prevalence, clinical manifestations, pathophysiology, and risk factors of statin-induced myopathy in diabetic patients. Among the diverse predisposing risk factors, the primary variables identified for causing myopathy in diabetic patients include age, gender, ethnicity, duration and severity of illness, comorbid conditions, level of physical activity, alcohol use, cholecalciferol (vitamin D3) levels, type and dose of statins, and anti-diabetic drugs or other drugs used concomitantly. In addition, cardiovascular risk quotients also potentially impact diabetic patients making them more vulnerable to developing myopathy from statins. Therefore, this study highlights the importance of managing statin-associated myopathic side effects by providing consensus guidelines on diagnostic, monitoring, and treatment strategies. We also discussed statins' prognostic value in reducing cardiovascular events in diabetic individuals.

The Benefits Outweigh the Risks of Treating Hypercholesterolemia: The Statin Dilemma

Cardiovascular diseases are one of the leading causes of death in the United States; therefore, primary and secondary prevention are of the utmost importance. In this regard, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMG-CoA) reductase inhibitors, also known as statins, have been anointed as the primary treatment method for lowering cholesterol to prevent cardiovascular diseases. Statins decrease the low-density lipoprotein (LDL) cholesterol and triglycerides in the body, thus lowering the total body cholesterol levels. Despite the benefits associated with statins, it is essential to understand the adverse effects of these drugs. Myotoxicity and statin-associated muscle symptoms are the most common adverse effects of statins. The impairment of mitochondrial function is another adverse effect that can lead to hepatic dysfunction, neurocognitive effects, and potentially the new onset of diabetes. The exact pathophysiology of these side effects is still not fully understood. However, several mechanisms have been proposed, although there is significant overlap among the hypothetical propositions. Understanding the overall outcomes of each of these adverse effects can allow a healthcare practitioner to carefully map out whether statin administration should be used to prevent hypercholesterolemia in the body. The adverse effect of statins is dependent on both the dose and the type of statin used. Lipophilic statins tend to possess a more remarkable ability to infiltrate membranes; they have been hypothesized to cause statin-induced myopathies as well as neurocognitive effects by significantly crossing the blood-brain barrier. In summary, this review has focused on the mechanistic and clinical aspects of this statin class of medication. Proposed mechanisms for different adverse effects associated with statins remain a focus of this communication.

Association Between Vitamin D and Statin-Related Myopathy: A Meta-analysis

BACKGROUND

Myopathy is the most widely reported statin-associated adverse event. Several studies have linked vitamin D deficiency with statin-related myopathy.

OBJECTIVE

This meta-analysis aimed to investigate whether adult patients with statin-related myopathy have a lower 25-hydroxyvitamin D (25OHD) level than patients without myopathy and whether statin-related myopathy in vitamin D-deficient patients can be improved by vitamin D supplementation.

METHODS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched until 28 September 2020. Original studies comparing the 25OHD levels of patients with and without myopathy or detecting the impact of vitamin D supplementation on statin-related muscular intolerance were included. Subgroup analyses based on the sample size and baseline 25OHD level were conducted.

RESULTS

This meta-analysis, based on nine cohort studies with a total of 2906 patients, revealed that the 25OHD level of patients with statin-related myopathy was significantly lower than that of patients without myopathy [weighted mean difference - 4.17 ng/mL; 95% confidence interval (CI) - 7.70 to - 0.63; p = 0.021]. The overall analysis from another four studies with 446 patients who were previously vitamin D deficient and reported statin-related muscular intolerance showed that the pooled tolerance rate of statins improved to 89% (95% CI 8692; p < 0.001) after vitamin D supplementation.

CONCLUSIONS

The present meta-analysis provides evidence that low 25OHD level is associated with statin-related myopathy and that exogenous vitamin D supplementation can improve statin-related muscular intolerance associated with low 25OHD level in most cases. Our findings may provide useful insight for the prevention and treatment of statin-related myopathy.

Sarcopenia and polypharmacy among older adults: A scoping review of the literature

BACKGROUND

Sarcopenia and polypharmacy are both prevalent conditions in the geriatric population, leading to poor quality of life and adverse outcomes.

OBJECTIVE

To explore the evidence on the relationship between sarcopenia and polypharmacy and to summarize the findings and the gaps from the existing literature.

METHOD

A systematic scoping review was conducted between March and May 2021, with no restriction on publication date, using the Arksey and O'Malley framework and reported according to PRISMA-ScR. Four bibliographic databases, PubMed, Web of Science, Scopus, Proquest One Academic, and four sources of gray literature were searched for studies written in English or Greek. Data were extracted quantitatively and using thematic analysis.

RESULTS

Of the 397 initially retrieved records, 22 studies were finally included in this review, 20 published articles and 2 posters-presentations. Most of the studies used cross-sectional data. The relationship between sarcopenia and polypharmacy should be interpreted on the basis of the definition of polypharmacy, the diagnostic criteria of sarcopenia used, and the population setting. Sarcopenia or risk for sarcopenia are associated with polypharmacy or the number of medications in community-dwelling older adults, regardless of diagnostic criteria used for sarcopenia.

CONCLUSION

There is an association between sarcopenia or risk for sarcopenia and polypharmacy or the number of medications in community-dwelling older adults but not among residents of nursing homes or inpatients. Specific widely accepted definitions of polypharmacy and sarcopenia, a consensus on the method of sarcopenia assessment, and prospective studies are needed to identify polypharmacy as a potential risk factor for sarcopenia.

Determination of Atorvastatin with Voltammetric Sensors Based on Nanomaterials

This paper presents an accurate and fast electrochemical method for atorvastatin determination in pharmaceutical products. Two screen-printed sensors, one—carbon based (SPCE) and one based on carbon nanotubes and gold nanoparticles (AuNP-CNT/SPCE) were used during the electrochemical analyses. At all experimental stages, cyclic voltammetry was employed, both for the characterization of the sensors and their electrochemical behavior, and for quantitative determinations. AuNP-CNT/SPCE has showed an extended active area, higher intensity peaks, better reversibility and lower background current than the unmodified sensor. For atorvastatin quantification, a calibration curve has been developed within the 1.2–606.25 µM concentration range. A linearity relation between the current of the anodic peak and concentration has been obtained in the range 1.2–53.33 µMfor both sensors. With the AuNP-CNT/SPCE sensor, low values of limit of detection, LOD (1.92 × 10−7 M) and limit of quantification, LOQ (6.39 × 10−7 M) have been obtained, which demonstrates the feasibility of the method of determining atorvastatin from real samples. Atorvastatin amount has been successfully determined from pharmaceutical products using AuNP-CNT/SPCE. The results were similar to the manufacturer’s specifications regarding the dosage per tablet and to the concentrations obtained by applying the FTIR spectrometric method.

Independent risk factors for simvastatin-related myopathy and relevance to different types of muscle symptom

Aims

Statins are widely used to prevent cardiovascular events, but little is known about the impact of different risk factors for statin-related myopathy or their relevance to reports of other types of muscle symptom.

Methods and results

An observational analysis was undertaken of 171 clinically adjudicated cases of myopathy (defined as unexplained muscle pain or weakness with creatine kinase >10× upper limit of normal) and, separately, of 15 208 cases of other muscle symptoms among 58 390 individuals with vascular disease treated with simvastatin for a mean of 3.4 years. Cox proportional hazards models were used to identify independent predictors of myopathy. The rate of myopathy was low: 9 per 10 000 person-years of simvastatin therapy. Independent risk factors for myopathy included: simvastatin dose, ethnicity, sex, age, body mass index, medically treated diabetes, concomitant use of niacin-laropiprant, verapamil, beta-blockers, diltiazem and diuretics. In combination, these risk factors predicted more than a 30-fold risk difference between the top and bottom thirds of a myopathy risk score (hazard ratio : 34.35, 95% CI: 12.73–92.69, P across thirds = 9·1 × 10⁻⁴⁸). However, despite the strong association with myopathy, this score was not associated with the other reported muscle symptoms (P across thirds = 0.93). Likewise, although SLCO1B1 genotype was associated with myopathy, it was not associated with other muscle symptoms.

Conclusions

The absolute risk of simvastatin-related myopathy is low, but individuals at higher risk can be identified to help guide patient management. The lack of association of the myopathy risk score with other muscle symptoms reinforces randomized placebo-controlled evidence that statins do not cause the vast majority of reported muscle symptoms.

LXRα/β Antagonism Protects against Lipid Accumulation in the Liver but Increases Plasma Cholesterol in Rhesus Macaques

Nonalcoholic fatty liver disease (NAFLD) is characterized by lipid accumulation in the liver and associates with obesity, hyperlipidemia, and insulin resistance. NAFLD could lead to nonalcoholic steatohepatitis (NASH), hepatic fibrosis, cirrhosis, and even cancers. The development of therapy for NAFLD has been proven difficult. Emerging evidence suggests that liver X receptor (LXR) antagonist is a potential treatment for fatty liver disease. However, concerns about the cholesterol-increasing effects make it questionable for the development of LXR antagonists. Here, the overweight monkeys were fed with LXRβ-selective antagonist sophoricoside or LXRα/β dual-antagonist morin for 3 months. The morphology of punctured liver tissues was examined by H&E staining. The liver, heart, and kidney damage indices were analyzed using plasma. The blood index was assayed using complete blood samples. We show that LXRβ-selective antagonist sophoricoside and LXRα/β dual-antagonist morin alleviated lipid accumulation in the liver in overweight monkeys. The compounds resulted in higher plasma TC or LDL-c contents, increased white blood cell and lymphocyte count, and decreased neutrophile granulocyte count in the monkeys. The compounds did not alter plasma glucose, apolipoprotein A (ApoA), ApoB, ApoE, lipoprotein (a) (LPA), nonesterified fatty acid (NEFA), aspartate transaminases (AST), creatinine (CREA), urea nitrogen (UN), and creatine kinase (CK) levels. Our data suggest that LXRβ-selective and LXRα/β dual antagonism may lead to hypercholesterolemia in nonhuman primates, which calls into question the development of LXR antagonist as a therapy for NAFLD.

Breath isoprene excretion during rest and low-intensity cycling exercise is associated with skeletal muscle mass in healthy human subjects

The physiological roles of isoprene, which is one of the many endogenous volatile organic compounds contained in exhaled breath, are not well understood. In recent years, exhaled isoprene has been associated with the skeletal muscle. Some studies have suggested that the skeletal muscle produces and/or stores some of the isoprene. However, the evidence supporting this association remains sparse and inconclusive. Furthermore, aging may affect breath isoprene response because of changes in the skeletal muscle quantity and quality. Therefore, we investigated the association between the breath isoprene excretion ([Formula: see text]) and skeletal muscle mass in young (n = 7) and old (n = 7) adults. The participants performed an 18 min cycling exercise after a 3 min rest. The workload corresponded to an intensity of 30% of the heart rate reserve, as calculated by the Karvonen formula. The exhaled breath of each participant was collected during the exercise test. We calculated [Formula: see text] from the product minute ventilation and isoprene concentration and, then, investigated the relationships between [Formula: see text] and muscle mass, which was measured by multi-frequency bioelectrical impedance analysis. Importantly, muscle mass persisted as a significant determinant that explained the variance in [Formula: see text] at rest even after adjusting for age. Furthermore, the muscle mass was a significant determinative factor for [Formula: see text] response during exercise, regardless of age. These data indicated that skeletal muscle mass could be one of the determinative factors for [Formula: see text] during rest and response to exercise. Thus, we suggest that the skeletal muscle may play an important role in generating and/or storing some of the endogenous isoprene. This new knowledge will help to better understand the physiological functions of isoprene in humans (Approval No. 20190079).

Lysophosphatidic Acid Inhibits Simvastatin-Induced Myocytoxicity by Activating LPA Receptor/PKC Pathway

Statins such as simvastatin have many side effects, including muscle damage, which is known to be the most frequent undesirable side effect. Lysophosphatidic acid (LPA), a kind of biolipid, has diverse cellular activities, including cell proliferation, survival, and migration. However, whether LPA affects statin-linked muscle damage has not been reported yet. In the present study, to determine whether LPA might exert potential protective effect on statin-induced myocyotoxicity, the effect of LPA on cytotoxicity in rat L6 myoblasts exposed to simvastatin was explored. Viability and apoptosis of rat L6 myoblasts were detected via 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5- [(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) assay and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, respectively. Protein expression levels were detected via Western blotting. Simvastatin decreased viability of L6 cells. Such decrease in viability was recovered in the presence of LPA. Treatment with LPA suppressed simvastatin-induced apoptosis in L6 cells. In addition, treatment with LPA receptor inhibitor Ki16425, protein kinase C (PKC) inhibitor GF109203X, or intracellular calcium chelator BAPTA-AM attenuated the recovery effect of LPA on simvastatin-induced L6 cell toxicity. These findings indicate that LPA may inhibit simvastatin-induced toxicity in L6 cells probably by activating the LPA receptor-PKC pathway. Therefore, LPA might have potential as a bioactive molecule to protect muscles against simvastatin-induced myotoxicity.

The protective effects of Salvia officinalis essential oil compared to simvastatin against hyperlipidemia, liver, and kidney injuries in mice submitted to a high-fat diet

The present study was undertaken to evaluate the effects of Salvia officinalis essential oil (SEO) and simvastatin in hyperlipidemic mice. Animals were randomly divided into four groups. The control group received a standard diet. The high-fat diet (HFD) group received HFD. The third and fourth groups received HFD associated either with simvastatin (2.5 mg/kg bw) or with SEO (4 mg/kg bw). All animals were sacrificed after 8 weeks of treatment. SEO and simvastatin reduced in HFD mice body weight gain, hyperlipidemia, disruption of liver and renal functions and reactive oxygen species production. In fact, total cholesterol, triglycerides, total lipids, and low-density lipoprotein cholesterol levels, as well as aspartate transaminase, alanine transaminase, gamma-glutamyltranspeptidase and lactate dehydrogenase activities were reduced, while fecal lipids increased compared to those of HFD mice. The lipid-lowering effect of SEO was more effective than that of simvastatin. PRACTICAL APPLICATIONS: High-fat diet provokes hyperlipidemia, atherosclerosis, and abnormal lipid metabolism leading to the development of hepatic and renal dysfunctions as well as perturbations of the antioxidant status in liver and kidney. The results of this research highlight the beneficial effects of SEO in the management of these disorders without inducing side effects; in fact, the plant essential oil decreased lipids and improved the antioxidant status more than did a synthetic drug.

Muscle Toxicity of Drugs: When Drugs Turn Physiology into Pathophysiology

Drugs are prescribed to manage or prevent symptoms and diseases, but may sometimes cause unexpected toxicity to muscles. The symptomatology and clinical manifestations of the myotoxic reaction can vary significantly between drugs and between patients on the same drug. This poses a challenge on how to recognize and prevent the occurrence of drug-induced muscle toxicity. The key to appropriate management of myotoxicity is prompt recognition that symptoms of patients may be drug related and to be aware that inter-individual differences in susceptibility to drug-induced toxicity exist. The most prevalent and well-documented drug class with unintended myotoxicity are the statins, but even today new classes of drugs with unintended myotoxicity are being discovered. This review will start off by explaining the principles of drug-induced myotoxicity and the different terminologies used to distinguish between grades of toxicity. The main part of the review will focus on the most important pathogenic mechanisms by which drugs can cause muscle toxicity, which will be exemplified by drugs with high risk of muscle toxicity. This will be done by providing information on key clinical and laboratory aspects, muscle electromyography patterns and biopsy results, and pathological mechanism and management for a specific drug from each pathogenic classification. In addition, rather new classes of drugs with unintended myotoxicity will be highlighted. Furthermore, we will explain why it is so difficult to diagnose drug-induced myotoxicity, and which tests can be used as a diagnostic aid. Lastly, a brief description will be given of how to manage and treat drug-induced myotoxicity.

Does Coenzyme Q10 Supplementation Mitigate Statin-Associated Muscle Symptoms? Pharmacological and Methodological Considerations

Statin drugs markedly reduce low-density lipoprotein cholesterol and consequently the incidence of cardiac events. In approximately 5-10% of adults, these drugs are associated with a range of muscle side effects such as muscle pain, cramping and weakness. Reduction in mitochondrial coenzyme Q10 (CoQ10), or ubiquinone, has been proposed as a mechanism for these statin-associated muscle symptoms (SAMS), and thus various formulations of CoQ10 are marketed and consumed for the prevention and treatment of SAMS. However, data supporting the efficacy of CoQ10 are equivocal, with some studies showing that CoQ10 supplementation reduces the incidence and severity of SAMS and others finding no beneficial effects of supplementation. Methodological and pharmacological issues may confound interpretation of data on this topic. For example, many patients who report SAMS, such as those who have been enrolled in previous CoQ10 studies, may be experiencing non-specific (non-statin-associated) muscle pain. In addition, the effectiveness of oral CoQ10 supplementation to increase mitochondrial CoQ10 in human skeletal muscle is not well established. This manuscript will critically evaluate the published data on the efficacy of CoQ10 supplements in the prevention and treatment of SAMS.

Effect of Statin Treatment vs Usual Care on Primary Cardiovascular Prevention Among Older Adults: The ALLHAT-LLT Randomized Clinical Trial

IMPORTANCE

While statin therapy for primary cardiovascular prevention has been associated with reductions in cardiovascular morbidity, the effect on all-cause mortality has been variable. There is little evidence to guide the use of statins for primary prevention in adults 75 years and older.

OBJECTIVES

To examine statin treatment among adults aged 65 to 74 years and 75 years and older when used for primary prevention in the Lipid-Lowering Trial (LLT) component of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT-LLT).

DESIGN, SETTING, AND PARTICIPANTS

Post hoc secondary data analyses were conducted of participants 65 years and older without evidence of atherosclerotic cardiovascular disease; 2867 ambulatory adults with hypertension and without baseline atherosclerotic cardiovascular disease were included. The ALLHAT-LLT was conducted from February 1994 to March 2002 at 513 clinical sites.

INTERVENTIONS

Pravastatin sodium (40 mg/d) vs usual care (UC).

MAIN OUTCOMES AND MEASURES

The primary outcome in the ALLHAT-LLT was all-cause mortality. Secondary outcomes included cause-specific mortality and nonfatal myocardial infarction or fatal coronary heart disease combined (coronary heart disease events).

RESULTS

There were 1467 participants (mean [SD] age, 71.3 [5.2] years) in the pravastatin group (48.0% [n = 704] female) and 1400 participants (mean [SD] age, 71.2 [5.2] years) in the UC group (50.8% [n = 711] female). The baseline mean (SD) low-density lipoprotein cholesterol levels were 147.7 (19.8) mg/dL in the pravastatin group and 147.6 (19.4) mg/dL in the UC group; by year 6, the mean (SD) low-density lipoprotein cholesterol levels were 109.1 (35.4) mg/dL in the pravastatin group and 128.8 (27.5) mg/dL in the UC group. At year 6, of the participants assigned to pravastatin, 42 of 253 (16.6%) were not taking any statin; 71.0% in the UC group were not taking any statin. The hazard ratios for all-cause mortality in the pravastatin group vs the UC group were 1.18 (95% CI, 0.97-1.42; P = .09) for all adults 65 years and older, 1.08 (95% CI, 0.85-1.37; P = .55) for adults aged 65 to 74 years, and 1.34 (95% CI, 0.98-1.84; P = .07) for adults 75 years and older. Coronary heart disease event rates were not significantly different among the groups. In multivariable regression, the results remained nonsignificant, and there was no significant interaction between treatment group and age.

CONCLUSIONS AND RELEVANCE

No benefit was found when pravastatin was given for primary prevention to older adults with moderate hyperlipidemia and hypertension, and a nonsignificant direction toward increased all-cause mortality with pravastatin was observed among adults 75 years and older.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00000542.

Polypharmacy and sun exposure: Implications for mitochondrial DNA deletions in skin

Most somatic cells contain many copies of mitochondrial DNA (mtDNA). Because of both the high copy number and the lack of repair mechanisms available to mtDNA, damage to it largely goes unrepaired, and can accumulate over time. Large scale deletions are a recognised type of damage sustained by mtDNA as a consequence of exposure to the ultraviolet light in sunlight. A group of patients were identified as having abnormally high levels of either a 4977 base pair deletion (mtDNA⁴⁹⁷⁷) or 3895 base pair deletion (mtDNA³⁸⁹⁵), in mtDNA from sun exposed skin or skin suspected to be a non-melanoma skin cancer, but not in their non-sun exposed skin biopsies. In three of the four cases, skin cancer was ruled out due to histological testing. Additional factors from these patients' medical histories were studied, and it was noted that they shared diagnoses for multiple pathologies common to an older population, and that they were being treated with the same or related pharmaceuticals, including some that had been known to cause dermal side effects. Investigation into the biochemistry underlying the symptoms, the effects of sun exposure and side effects of the prescribed pharmaceuticals revealed a possible synergistic relationship leading to the localised high levels of mtDNA deletions.

Effects of Different Types of Statins on Lipid Profile: A Perspective on Asians

CONTEXT

The present review aimed at reviewing the effects of different statins on lipid profile, particularly in Asians.

EVIDENCE ACQUISITION

PubMed searches were conducted using the keywords 'statin, effect, and lipid profile' from database inception through March 2016. In this review, 718 articles were retrieved from the primary search. After reviewing the titles, abstracts, and full texts, we found that 59 studies met our inclusion criteria. These also included subsequent reference searches of retrieved articles.

RESULTS

CURVES study compared the effect on lipid profile between atorvastatin and other statins. This study demonstrated that low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG) were reduced more with atorvastatin compared to simvastatin, pravastatin, lovastatin, and fluvastatin. However, simvastatin provided a greater elevation of high-density lipoprotein cholesterol (HDL-C) compared to atorvastatin. The STELLAR trial was based on dose-to-dose comparisons between atorvastatin and rosuvastatin efficacy in reducing LDL-C. Te present study also revealed that as the doses of rosuvastatin, simvastatin, and pravastatin increased, HDL-C also increased, with rosuvastatin having the greatest effect. However, HDL-C levels decreased as the dose of atorvastatin increased. The DISCOVERY study involving the Asian population revealed that the percentage of patients achieving the European goals for LDL-C and TC at 12 weeks was higher in rosuvastatin group compared to atorvastatin group.

CONCLUSIONS

The effects of statins on lipid profile are dose dependent. Most studies showed that rosuvastatin has the best effect on lipid profile. Prescribing lower doses of statins in Asians seems necessary.

Statin-associated myopathy and the quest for biomarkers: can we effectively predict statin-associated muscle symptoms?

Over the past three decades, statins have become the cornerstone of prevention and treatment of atherosclerotic cardiovascular and metabolic diseases. Albeit generally well tolerated, these drugs can elicit a variety of muscle-associated symptoms that represent the most important reason for treatment discontinuation. Statin-associated myopathy has been systematically underestimated by randomized controlled trials as compared with the incidence observed in clinical practice and obtained from patient registries. There are several reasons for this discrepancy, among which the lack of reliable diagnostic tests and a validated questionnaire to assess muscle symptoms are recognized as unmet needs. Here, we review the cellular and molecular mechanisms underlying statin-associated myopathy and discuss the experimental and clinical data on various biomarkers to diagnose and predict muscle-related complaints.

Laboratory Medicine in the Clinical Decision Support for Treatment of Hypercholesterolemia: Pharmacogenetics of Statins

Statin responsiveness is an area of great research interest given the success of the drug class in the treatment of hypercholesterolemia and in primary and secondary prevention of cardiovascular disease. Interrogation of the patient's genome for gene variants will eventually guide anti-hyperlipidemic intervention. In this review, we discuss methodological approaches to discover genetic markers predictive of class-wide and drug-specific statin efficacy and safety. Notable pharmacogenetic findings are summarized from hypothesis-free genome wide and hypothesis-led candidate gene association studies. Physiogenomic models and clinical decision support systems will be required for DNA-guided statin therapy to reach practical use in medicine.

The frequency of SLCO1B1*5 polymorphism genotypes among Russian and Sakha (Yakutia) patients with hypercholesterolemia

Introduction

Statins are the most commonly prescribed medicines for treatment of hypercholesterolemia. At the same time, up to 25% of patients cannot tolerate or have to discontinue the statin therapy due to statin-induced myopathy. In a majority of cases, statin-induced myopathy is attributed to SLCO1B1 gene polymorphism. The strongest association between statin-induced myopathy and SLCO1B1 gene polymorphism was described for simvastatin. Our research was focused on the frequency of SLCO1B1*5 genetic variant in the Russian population and in the native population of Sakha (Yakutia).

Materials and methods

A total of 1,071 hyperlipidemic Russian and 76 hyperlipidemic Sakha (Yakutian) patients were included in the study. Genotypes of SLCO1B1*5 (c.521T>C, rs4149056) were determined with polymerase chain reaction amplification. The results of our study were compared with data about hyperlipidemic patients in available publications.

Results

In the Russian population 665 (62%) patients had TT genotype of SLCO1B1*5, 346 (32%) patients had TC genotype, and in 60 patients (6%) CC variant was found (Hardy–Weinberg’s chi-square test was 3.1 P=0.21). In comparison with Brazil, France, the People’s Republic of China, Japan, and the native population of Sakha (Yakutia), C-allele, which causes an increased risk of statin-induced myopathy, was found significantly more often in the Russian population. In the native population of Sakha (Yakutia) SLCO1B1 polymorphism was TT – 62 (82%), TC – 11 (14%), CC – 3 (4%) (Hardy–Weinberg’s chi-square test was 5.13 P=0.077). In comparison with data from Brazil, France, the People’s Republic of China, and Japan, C-allele frequency in the Sakha (Yakutian) population was not significantly different.

Conclusion

Thus, we have studied the incidence of pathologic SLCO1B1 c.521C-allele in Russian and Sakha hyperlipidemic patients. The presence of SLCO1B1 C-allele in patients with hyperlipidemia forces us to be more careful in hypolipidemic drug prescription, especially statins, according to a higher risk of statin-induced myopathy development. The fact that SLCO1B1 C-allele is rarer among Sakha patients, could be interesting from the point of studying adverse drug effects frequency and statins’ effectiveness.

Association Between SLCO1B1 Gene T521C Polymorphism and Statin-Related Myopathy Risk: A Meta-Analysis of Case-Control Studies

Statin-related myopathy is an important adverse effect of statin which is classically unpredictable. The evidence of association between solute carrier organic anion transporter 1B1 (SLCO1B1) gene T521C polymorphism and statin-related myopathy risk remained controversial. This study aimed to investigate this genetic association. Databases of PubMed, EMBASE, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database, and Wanfang Data were searched till June 17, 2015. Case-control studies investigating the association between SLCO1B1 gene T521C polymorphism and statin-related myopathy risk were included. The Newcastle-Ottawa Scale (NOS) was used for assessing the quality of included studies. Data were pooled by odds ratios (ORs) and their 95% confidence intervals (CIs). Nine studies with 1360 cases and 3082 controls were included. Cases of statin-related myopathy were found to be significantly associated with the variant C allele (TC + CC vs TT: OR = 2.09, 95% CI = 1.27-3.43, P = 0.003; C vs T: OR = 2.10, 95% CI = 1.43-3.09, P < 0.001), especially when statin-related myopathy was defined as an elevation of creatine kinase (CK) >10 times the upper limit of normal (ULN) or rhabdomyolysis (TC + CC vs TT: OR = 3.83, 95% CI = 1.41-10.39, P = 0.008; C vs T: OR = 2.94, 95% CI = 1.47-5.89, P = 0.002). When stratified by statin type, the association was significant in individuals receiving simvastatin (TC + CC vs TT: OR = 3.09, 95% CI = 1.64-5.85, P = 0.001; C vs T: OR = 3.00, 95% CI = 1.38-6.49, P = 0.005), but not in those receiving atorvastatin (TC + CC vs TT: OR = 1.31, 95% CI = 0.74-2.30, P = 0.35; C vs T: OR = 1.33, 95% CI = 0.57-3.12, P = 0.52). The available evidence suggests that SLCO1B1 gene T521C polymorphism is associated with an increased risk of statin-related myopathy, especially in individuals receiving simvastatin. Thus, a genetic test before initiation of statins may be meaningful for personalizing the treatment.

Evidence for metabolic aberrations in asymptomatic persons with type 2 diabetes after initiation of simvastatin therapy

Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) prevent vascular events and are widely prescribed, particularly in persons with type 2 diabetes. However, intolerability because of myopathic symptoms often limits their use. We investigated the effects of simvastatin on parameters of mitochondrial function and muscle gene expression in 11 subjects with type 2 diabetes, none of whom had statin intolerance. After withdrawal of statins for 2 months, we obtained blood samples, performed vastus lateralis muscle biopsies, and assessed whole body resting energy expenditure (REE). We then reinitiated therapy using simvastatin, 20 mg/d, for 1 month before repeating these studies. As expected, simvastatin lowered low-density lipoprotein, but did not induce myalgias or significant increases in serum creatine kinase. However, we found subtle but significant reductions in muscle citrate synthase activity and REE. In addition, quantitative polymerase chain reaction and gene set enrichment analysis of muscle samples revealed significantly repressed gene sets involved in mitochondrial function and induced gene sets involved in remodeling of the extracellular matrix. Furthermore, the effects of simvastatin on muscle gene sets showed some similarities to previously described changes that occur in Duchenne muscular dystrophy, polymyositis, and dermatomyositis. Although statins inhibit an early step in coenzyme Q (CoQ) biosynthesis, we observed no differences in CoQ content within skeletal muscle mitochondria, muscle tissue, or circulating platelets. In summary, we report subtle changes in whole body energetics, mitochondrial citrate synthase activity, and microarray data consistent with subclinical myopathy. Although the benefits of statin therapy are clear, further understanding of muscular perturbations should help guide safety and tolerability.

Statin therapy and plasma coenzyme Q10 concentrations--A systematic review and meta-analysis of placebo-controlled trials

Statin therapy may lower plasma coenzyme Q10 (CoQ10) concentrations, but the evidence as to the significance of this effect is unclear. We assessed the impact of statin therapy on plasma CoQ10 concentrations through the meta-analysis of available RCTs. The literature search included selected databases up to April 30, 2015. The meta-analysis was performed using either a fixed-effects or random-effect model according to I(2) statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). The data from 8 placebo-controlled treatment arms suggested a significant reduction in plasma CoQ10 concentrations following treatment with statins (WMD: -0.44 μmol/L, 95%CI: -0.52, -0.37, p<0.001). The pooled effect size was robust and remained significant in the leave-one-out sensitivity analysis. Subgroup analysis suggested that the impact of statins on plasma CoQ10 concentrations is significant for all 4 types of statins studied i.e. atorvastatin (WMD: -0.41 μmol/L, 95%CI: -0.53, -0.29, p<0.001), simvastatin (WMD: -0.47 μmol/L, 95% CI: -0.61, -0.33, p<0.001), rosuvastatin (WMD: -0.49 μmol/L, 95%CI: -0.67, -0.31, p<0.001) and pravastatin (WMD: -0.43 μmol/L, 95%CI: -0.69, -0.16, p=0.001). Likewise, there was no differential effect of lipophilic (WMD: -0.43 μmol/L, 95%CI: -0.53, -0.34, p<0.001) and hydrophilic statins (WMD: -0.47 μmol/L, 95%CI: -0.62, -0.32, p<0.001). With respect to treatment duration, a significant effect was observed in both subsets of trials lasting <12 weeks (WMD: -0.51 μmol/L, 95%CI: -0.64, -0.39, p<0.001) and ≥12 weeks (WMD: -0.40 μmol/L, 95%CI: -0.50, -0.30, p<0.001). The meta-analysis showed a significant reduction in plasma CoQ10 concentrations following treatment with statins. Further well-designed trials are required to confirm our findings and elucidate their clinical relevance.

Predictors and outcomes of increases in creatine phosphokinase concentrations or rhabdomyolysis risk during statin treatment

AIM

The aim was to evaluate clinical risk factors associated with myotoxicity in statin users.

METHODS

This was a cohort study of patients prescribed a statin in UK primary care practices contributing to the Clinical Practice Research Datalink. Outcomes of interest were creatine phosphokinase (CPK) concentrations and clinical records of rhabdomyolysis.

RESULTS

The cohort comprised 641,703 statin users. Simvastatin was most frequently prescribed (66.3%), followed by atorvastatin (24.4%). CPK was measured in 127,209 patients: 81.4% within normal range and 0.7% above <four times the upper limit of normal (ULN). Rhabdomyolysis was recorded in 59 patients. Patients with concomitant prescribing of CYP3A4-interacting drugs had an increased odds ratio (OR) of rhabdomyolysis compared with controls (OR 3.71, 95% CI 1.18, 11.61) and >four times ULN CPK compared with normal CPK (OR 1.28, 95% CI 1.01, 1.60). Rosuvastatin users had higher risk of >four times ULN CPK (OR 1.62, 95% CI 1.22, 2.15) as did patients with larger daily doses of other statin types. A recent clinical record of myalgia was associated with an increased OR of >four times ULN CPK (OR 1.73, 95% CI 1.37, 2.18). In patients who were rechallenged to statins and had repeat CPK measurements after >four times ULN CPK abnormalities, 54.8% of the repeat CPK values were within normal range, 32.1% between one to three times and 13.0% >four times ULN.

CONCLUSIONS

The frequencies of substantive CPK increases and rhabdomyolysis during statin treatment were low, with highest risks seen in those on large daily doses or interacting drugs and on rosuvastatin. CPK measurements appeared to have been done in a haphazard manner and better guidance is needed.

Evaluation of sexual dimorphism in the efficacy and safety of simvastatin/atorvastatin therapy in a southern Brazilian cohort

BACKGROUND

Dyslipidemia is the primary risk factor for cardiovascular disease, and statins have been effective in controlling lipid levels. Sex differences in the pharmacokinetics and pharmacodynamics of statins contribute to interindividual variations in drug efficacy and toxicity.

OBJECTIVE

To evaluate the presence of sexual dimorphism in the efficacy and safety of simvastatin/atorvastatin treatment.

METHODS

Lipid levels of 495 patients (331 women and 164 men) were measured at baseline and after 6 ± 3 months of simvastatin/atorvastatin treatment to assess the efficacy and safety profiles of both drugs.

RESULTS

Women had higher baseline levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) compared with men (p < 0.0001). After treatment, women exhibited a greater decrease in plasma TC and LDL-C levels compared with men. After adjustment for covariates, baseline levels of TC and LDL-C influenced more than 30% of the efficacy of lipid-lowering therapy (p < 0.001), regardless of sex. Myalgia [with or without changes in creatine phosphokinase (CPK) levels] occurred more frequently in women (25.9%; p = 0.002), whereas an increase in CPK and/or abnormal liver function was more frequent in in men (17.9%; p = 0.017).

CONCLUSIONS

Our results show that baseline TC and LDL-C levels are the main predictors of simvastatin/atorvastatin therapy efficacy, regardless of sex. In addition, they suggest the presence of sexual dimorphism in the safety of simvastatin/atorvastatin. The effect of sex differences on receptors, transporter proteins, and gene expression pathways needs to be better evaluated and characterized to confirm these observations.

Genetic and immunologic susceptibility to statin-related myopathy

Statin-related myopathy (SRM) undermines drug adherence that is critical for achieving the benefits of lipid-lowering therapy. While the exact mechanism of SRM remains largely unknown, recent evidence supports specific genetic and immunologic influence on the development of intolerance. Genes of interest include those involved in the pharmacokinetics of statin response (i.e. drug metabolism, uptake transporters, and efflux transporters), pharmacodynamics (i.e. drug toxicity and immune-mediated myopathy), and gene expression. We examine the influence of genetic and immunologic variation on the pharmacokinetics, pharmacodynamics, and gene expression of SRM.

Electronic health records for biological sample collection: feasibility study of statin-induced myopathy using the Clinical Practice Research Datalink

AIMS

Electronic healthcare records (EHRs) are increasingly used to store clinical information. A secondary benefit of EHRs is their use, in an anonymized form, for observational research. The Clinical Practice Research Datalink (CPRD) contains EHRs from primary care in the UK and, despite 1083 peer-reviewed research publications, has never been used to obtain pharmacogenetic samples. Using a statin-induced myopathy paradigm, we evaluated using the CPRD to obtain patient samples for a pharmacogenetic study targeting 250 cases and 500 controls from UK general practitioner (GP) practices.

METHODS

The CPRD identified potential patients fitting specific case-definition criteria (active rhabdomyolysis or creatine phosphokinase > four times the upper limit of normal), and corresponding GP practices were asked to invite patient participation. Consenting patients were requested to provide either saliva or blood samples and to complete an ethnicity questionnaire. Control subjects were recruited from the same GP practice (saliva) or a small number of practices (blood). Samples were forwarded for DNA extraction.

RESULTS

Thirty-six months of recruitment yielded DNA samples from 149 statin-induced myopathy cases and 587 tolerant controls. Data show that contacting patients through their GP is a reliable method for obtaining samples without compromising anonymity. Saliva collection directly from patients was considerably less effective than blood sampling. After 10 months of recruitment, saliva sampling was suspended in favour of blood sampling.

CONCLUSIONS

We demonstrate the potential of EHRs for identifying accurately phenotyped cases and controls for pharmacogenetic studies. Recruitment was successful only because of the willingness of GP practices to participate and the existence of strong doctor–patient relationships. The present study provides a model that can be implemented in future genetic analyses using EHRs.

Statin-induced Myopathy in Skeletal Muscle: the Role of Exercise

Statins are widely used drugs to lower cholesterol levels and to reduce the risk of cardiovascular disease. However, it has been reported that statins are associated with adverse side effects of skeletal myopathy. Statin treatment can impair mitochondrial function and induce apoptosis in skeletal muscle in both human and animal models. Ubiquinone plays an essential role in transferring electrons in the mitochondrial electron transfer chain for oxidative phosphorylation. However, statin treatment reduces ubiquinone levels in the cholesterol synthesis pathway, which may be associated with mitochondrial dysfunction. In addition, reactive oxygen species (ROS) production and apoptosis induced by statins may provide cellular and molecular mechanisms in skeletal myopathy. Exercise is the most effective therapy to prevent metabolic and cardiovascular diseases. However, whether exercise provides a benefit to or exacerbation of statin-induced myopathy in skeletal muscle remains poorly investigated. This review will briefly provide a comprehensive summary regarding the effects of statins on skeletal myopathy, and discuss the potential mechanisms of statin-induced myopathy and the role of exercise in statin-induced myopathy in skeletal muscle.

CKM and LILRB5 are associated with serum levels of creatine kinase

BACKGROUND

Statins (HMG-CoA reductase inhibitors) are the most prescribed class of lipid-lowering drugs for the treatment and prevention of cardiovascular disease. Creatine kinase (CK) is a commonly used biomarker to assist in the diagnosis of statin-induced myotoxicity but the normal range of CK concentrations is wide, which limits its use as a diagnostic biomarker.

METHODS AND RESULTS

We conducted a genome-wide association study of serum CK levels in 3412 statin users. Patients were recruited in Quebec, Canada, and genotyped on Illumina Human610-Quad and an iSelect panel enriched for lipid homeostasis, hypertension, and drug metabolism genes. We found a strong association signal between serum levels of CK and the muscle CK (CKM) gene (rs11559024: P=3.69×10(-16); R(2)=0.02) and with the leukocyte immunoglobulin-like receptor subfamily B member 5 (LILRB5) gene (rs2361797: P=1.96×10(-10); R(2)=0.01). Genetic variants in those 2 genes were independently associated with CK levels in statin users. Results were successfully replicated in 5330 participants from the Montreal Heart Institute Biobank in statin users for CKM (rs11559024: P=4.32×10(-16); R(2)=0.02) and LILRB5 (rs12975366 P=4.45×10(-10); R(2)=0.01) and statin nonusers (P=4.08×10(-7), R(2)=0.01; P=3.17×10(-9), R(2)=0.02, respectively).

CONCLUSIONS

This is the first genome-wide study to report on the underlying genetic determinants of CK variation in a population of statin users. We found statistically significant association for variants in the CKM and LILRB5 genes.

Impact of statin use on exercise-induced cardiac troponin elevations

Marathon running commonly causes a transient elevation of creatine kinase and cardiac troponin I (cTnI). The use of statins before marathon running exacerbates the release of creatine kinase from skeletal muscle, but the effect of statin use on exercise-induced cTnI release is unknown. We therefore measured cTnI concentrations in statin-using (n = 30) and nonstatin-using (n = 41) runners who participated in the 2011 Boston Marathon. All runners provided venous blood samples the day before, within an hour of finishing, and 24 hours after the marathon. cTnI was assessed at each time point via both a contemporary cTnI and high-sensitivity cTnI (hsTnI) assay. Before the marathon, cTnI was detectable in 99% of runners with the use of the hsTnI assay. All participants completed the marathon (finish time: 4:04:09 ± 0:41:10), and none had symptoms of an acute coronary syndrome. cTnI increased in all runners (p <0.001) immediately after the marathon, and half (hsTnI = 54% vs contemporary cTnI = 47%) exceeded the diagnostic cut-point for an acute myocardial infarction. Statin use did not affect the magnitude of cTnI release (group*time p = 0.47) or the incidence of runners with cTnI elevation greater than the diagnostic cut-point for myocardial infarction (57% vs 51%, p = 0.65). In addition, there was no significant association between statin potency and cTnI release (r = 0.09, p = 0.65). In conclusion, marathon-induced cTnI increases are not altered by statin use.

Statins and skeletal muscles toxicity: from clinical trials to everyday practice

The mechanism(s) underlying the occurrence of statin-induced myopathy are ill defined, but the results of observational studies and clinical trials provide compelling evidence that skeletal muscle toxicity is a frequent, dose-dependent, adverse event associated with all statins. It has been suggested that reduced availability of metabolites produced by the mevalonate pathway rather than intracellular cholesterol lowering per se might be the primary trigger of toxicity, however other alternative explanations have gained credibility in recent years. Aim of this review is: (i) to describe the molecular mechanisms associated to statin induced myopathy including defects in isoprenoids synthesis followed by altered prenylation of small GTPase, such as Ras and Rab proteins; (ii) to present the emerging aspects on pharmacogenetics, including CYP3A4, OATP1B1 and glycine amidinotransferase (GATM) polymorphisms impacting either statin bioavailability or creatine synthesis; (iii) to summarize the available epidemiological evidences; and (iii) to discuss the concepts that would be of interest to the clinicians for the daily management of patients with statin induced myopathy. The interplay between drug-environment and drug-drug interaction in the context of different genetic settings contribute to statins and skeletal muscles toxicity. Until specific assays/algorithms able to combine genetic scores with drug-drug-environment interaction to identify patients at risk of myopathies will become available, clinicians should continue to monitor carefully patients on polytherapy which include statins and be ready to reconsider dose, statin or switching to alternative treatments. The beneficial effects of adding agents to provide the muscle with the metabolites, such as CoQ10, affected by statin treatment will also be addressed.

Antihyperlipidemic effects of stilbenoids isolated from Morus alba in rats fed a high-cholesterol diet

Mulberroside A (MUL) was purified from an ethanol extract of Morus alba root, and oxyresveratrol (OXY) was produced by enzymatic conversion of MUL. Normal rats, Triton WR-1339-induced hyperlipidemic rats, and high-cholesterol diet (HCD)-induced hyperlipidemic rats were orally treated with MUL or OXY (1-5mg/kg/day). MUL and OXY were administered 1h prior to concomitant treatment with Triton WR-1339 for a further 24h, whereas the drugs were administered concurrently with HCD for 4weeks. Oral MUL and OXY pre-treatment vs. water pre-treatment of Triton WR-1339-induced hyperlipidemic rats significantly (p<0.05) reduced the levels of serum lipids in a dose-dependent manner, while high-density lipoprotein cholesterol (HDL-C, or "good" cholesterol) levels were increased. Oral MUL and OXY treatment of HCD-fed rats also showed a significant (p<0.05) dose-dependent decrease in serum lipids, coronary artery risk index (CRI), and atherogenic index (AI), but not HDL-C. Furthermore, MUL and OXY treatment of HCD-induced hyperlipidemic rats demonstrated a significant dose-dependent improvement in the histological features of hepatic fatty degeneration. Aspartate aminotransferase and alanine aminotransferase values in OXY-treated normal rats were not significantly different from those in water-treated control rats. These results indicate that MUL and OXY might be developed as novel antihyperlipidemic agents.

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.

Comparative efficacy and adverse effects of the addition of ezetimibe to statin versus statin titration in chronic kidney disease patients

BACKGROUND AND OBJECTIVES

The recent SHARP trial clearly demonstrated that a reduction in low-density lipoprotein (LDL) cholesterol with a daily regimen of simvastatin plus ezetimibe safely reduced the incidence of major atherosclerotic events in patients with chronic kidney disease (CKD). We aimed to compare the efficacy of and adverse effects from statin uptitration versus statin in combination with ezetimibe since only a few studies have addressed this question.

METHODS

This was a randomized, open-label, multicenter trial that included 286 patients with CKD whose LDL cholesterol levels were not reduced below 120 mg/dl despite a minimum dose of statin therapy. Patients received double doses of statin or usual statin dose with the addition of ezetimibe 10 mg daily. The observation period was 1 year during which time patients were checked regularly in clinic for adverse effects as well as for usual laboratory examinations. The key prespecified outcome was the incidence of adverse effects, which included skeletal muscle complaints, myalgia, muscle weakness, and muscle cramps with and without elevated CK levels. Increases in alanine transaminase (ALT) or aspartate transaminase (AST) levels >2 times the upper limit of normal (ULN) were considered clinically significant adverse effects.

RESULTS

Adverse events occurred in 9/145 in the combination group and in 24/141 in the statin uptitration group (p < 0.01). Moreover, in patients with CKD of stages 3-5, rates were 6/58 in the combination group versus 20/52 in the statin uptitration group (p < 0.01). No serious adverse effects such as rhabdomyolysis were noted in either group. Serum creatinine levels remained essentially unchanged in both groups except in CKD stages 4 and 5. Reductions in LDL cholesterol were similar between the two groups at the start of and at the end of the study. During the study, no atherosclerotic events were reported in either group.

CONCLUSION

When statin uptitration produces adverse effects such as myopathy, combination therapy with ezetimibe is recommended instead of statin alone.

A Clinical Review of Statin-Associated Myopathy

Objective: To review the epidemiology, clinical features, proposed mechanisms, risk factors, and management of statin-associated myopathy. Data Sources: Literature searches were conducted in PubMed (1948 to April 2013), TOXLINE, International Pharmaceutical Abstracts (1970 to April 2013), and Google Scholar using the terms statin, hydroxymethylglutaryl-coenzyme A reductase inhibitors, myopathy, myalgia, safety, and rhabdomyolysis. Results were limited to English publications. Study Selection and Data Extraction: All relevant original studies, guidelines, meta-analyses, and reviews of statin-associated myopathy and safety of statins were assessed for inclusion. References from selected articles were reviewed to identify additional citations. Data Synthesis: The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors remain one of the most effective medications for reducing low-density-lipoprotein cholesterol. Statins are well tolerated by most patients; however, it is estimated that 10% to 15% of patients develop statin-related muscle adverse effects known as statin-associated myopathy. Although clinicians may be aware of statin-associated myopathy, they may not be aware of its clinical presentation. Providers should assess individual patient risk factors before choosing the appropriate statin. A variety of skeletal muscle aches that may not present as a danger to the patient, may affect patient adherence and quality of life. There are several steps that providers can take to properly treat and manage patients with myalgia complaints. Conclusions: Statin-associated myopathy is a clinical problem that contributes to statin therapy discontinuation. Patients who are statin intolerant may be treated with alternative treatment options such as low-dose statins, switching statins, using alternative dosing strategies in statins with longer half-lives, non-statin lipid-lowering agents, and complementary therapies.

Influence of PPARA, RXRA, NR1I2 and NR1I3 gene polymorphisms on the lipid-lowering efficacy and safety of statin therapy

OBJECTIVE: The aim of the present study was investigate the association between six genetic variants in the nuclear receptor genes PPARA, RXRA, NR1I2 and NR1I3 and the lipid-lowering efficacy and safety of statin therapy. SUBJECTS AND METHODS: The study was carried out on 240 Brazilian hypercholesterolemic patients on simvastatin and atorvastatin therapy. The polymorphisms were analyzed by PCR-based methods. RESULTS: The NR1I3 rs2307424 genotype distribution was different between subjects with and without adverse drug reactions. Among subjects in the ADR group, no T/T homozygotes were observed for this polymorphism, while in the non-ADR group the frequency of this genotype was 19.4% (P = 0.007, after multiple testing corrections P = 0.042). CONCLUSION: The polymorphisms investigated in PPARA (rs1800206), RXRA (rs11381416), and NR1I2 (rs1523130) did not influence the lipid-lowering efficacy and safety of statin. Our results show the possible influence of NR1I3 genetic variant on the safety of statin.

Association of statin use with peripheral neuropathy in the U.S. population 40 years of age or older

BACKGROUND

Peripheral neuropathy is a serious complication of diabetes and several conditions that may lead to the loss of lower extremity function and even amputations. Since the introduction of statins, their use has increased markedly. Recent reports suggest a role for statins in the development of peripheral neuropathy. The aims of the present study were to assess the association between statin use and peripheral neuropathy, and to determine whether this association varied by diabetes status.

METHODS

Data from the lower extremity examination supplement of the 1999-2004 National Health and Nutrition Examination Survey were used.

RESULTS

The overall prevalence of statin use was 15% and the prevalence of peripheral neuropathy was 14.9%. The prevalence of peripheral neuropathy was significantly higher among those who used statins compared with those who did not (23.5% vs 13.5%, respectively; P < 0.01). Multivariate logistic regression revealed that statin use (adjusted odds ratio 1.3; 95% confidence interval 1.1-1.6; Wald P = 0.04) was significantly associated with peripheral neuropathy, controlling for diabetes status, age, gender, race, height, weight, blood lead levels, poverty, glycohemoglobin, use of vitamin B12 , alcohol abuse, hypertension, and non-high-density lipoprotein-cholesterol. Diabetes status, age, gender, height, weight, blood lead levels, poverty, and glycohemoglobin were also significantly associated with peripheral neuropathy. We found no effect modification between statin use and diabetes status, race, gender, age, vitamin B12 , blood lead levels, or alcohol abuse.

CONCLUSIONS

In the present cross-sectional study, we found a modest association between peripheral neuropathy and statin use. Prospective studies are required to determine the causal direction.

Perioperative genomics

Since the completion of the Human Genome Project 10 years ago, the world has witnessed an incredible progress in human genetics and genomics.(1) This progress was largely driven by the availability of better, faster and cheaper sequencing technology.(2) While it took more than 10 years and more than 1 billion dollars to complete the Human Genome Project,(3-5) an individual in the year 2011 can have his whole genome sequenced within a week for less than $30,000. With cheaper and faster sequencing came a wealth of novel discoveries which makes it timely to review how these newly found insights into the human genome are relevant for perioperative medicine. This article summarises the basics of genetic inheritance, the human genome and modern sequencing methods, as well as genetic variation and how this knowledge may be applied to patient care and research in the perioperative setting.

Simvastatin impairs ADP-stimulated respiration and increases mitochondrial oxidative stress in primary human skeletal myotubes

Statins, the widely prescribed cholesterol-lowering drugs for the treatment of cardiovascular disease, cause adverse skeletal muscle side effects ranging from fatigue to fatal rhabdomyolysis. The purpose of this study was to determine the effects of simvastatin on mitochondrial respiration, oxidative stress, and cell death in differentiated primary human skeletal muscle cells (i.e., myotubes). Simvastatin induced a dose-dependent decrease in viability of proliferating and differentiating primary human muscle precursor cells, and a similar dose-dependent effect was noted in differentiated myoblasts and myotubes. Additionally, there were decreases in myotube number and size following 48 h of simvastatin treatment (5 μM). In permeabilized myotubes, maximal ADP-stimulated oxygen consumption, supported by palmitoylcarnitine+malate (PCM, complex I and II substrates) and glutamate+malate (GM, complex I substrates), was 32-37% lower (P<0.05) in simvastatin-treated (5 μM) vs control myotubes, providing evidence of impaired respiration at complex I. Mitochondrial superoxide and hydrogen peroxide generation were significantly greater in the simvastatin-treated human skeletal myotube cultures compared to control. In addition, simvastatin markedly increased protein levels of Bax (proapoptotic, +53%) and Bcl-2 (antiapoptotic, +100%, P<0.05), mitochondrial PTP opening (+44%, P<0.05), and TUNEL-positive nuclei in human skeletal myotubes, demonstrating up-regulation of mitochondrial-mediated myonuclear apoptotic mechanisms. These data demonstrate that simvastatin induces myotube atrophy and cell loss associated with impaired ADP-stimulated maximal mitochondrial respiratory capacity, mitochondrial oxidative stress, and apoptosis in primary human skeletal myotubes, suggesting that mitochondrial dysfunction may underlie human statin-induced myopathy.

Statin-induced myopathy: a review and update

INTRODUCTION

Statin-induced myopathy is an important cause of statin intolerance and the most common cause of statin discontinuation. Observational studies estimate that 10 - 15% of statin users develop statin-related muscle side effects ranging from mild myalgia to more severe muscle symptoms with significant CPK elevations.

AREAS COVERED

This article reviews the epidemiology, clinical features, risk factors and mechanisms of statin-induced myopathy and provides an evidence-based algorithm for managing patients with statin myopathy.

EXPERT OPINION

There are multiple risk factors for statin-induced myopathy that are both patient-related (age, genetics, co-morbidities) and drug-related (statin metabolism via the CYP system, drug-drug interactions and statin drug transport). Management options for statin-intolerant patients include statin switching, especially to low-dose, non-daily doses of long-acting statins, such as rosuvastatin and atorvastatin, and other non-statin lipid-lowering agents, such as ezetimibe and colesevelam, and possibly red yeast rice. In conclusion, statin-induced myopathy is a significant clinical problem that contributes considerably to statin therapy discontinuation. However, there exist multiple and effective management options for statin intolerant patients.