Genetic and immunologic susceptibility to statin-related myopathy

Leveraging large-scale biobank EHRs to enhance pharmacogenetics of cardiometabolic disease medications

Electronic health records (EHRs) coupled with large-scale biobanks offer great promises to unravel the genetic underpinnings of treatment efficacy. However, medication-induced biomarker trajectories stemming from such records remain poorly studied. Here, we extract clinical and medication prescription data from EHRs and conduct GWAS and rare variant burden tests in the UK Biobank (discovery) and the All of Us program (replication) on ten cardiometabolic drug response outcomes including lipid response to statins, HbA1c response to metformin and blood pressure response to antihypertensives (N = 740-26,669). Our findings at genome-wide significance level recover previously reported pharmacogenetic signals and also include novel associations for lipid response to statins (N = 26,669) near LDLR and ZNF800. Importantly, these associations are treatment-specific and not associated with biomarker progression in medication-naive individuals. Furthermore, we demonstrate that individuals with higher genetically determined low-density and total cholesterol baseline levels experience increased absolute, albeit lower relative biomarker reduction following statin treatment. In summary, we systematically investigated the common and rare pharmacogenetic contribution to cardiometabolic drug response phenotypes in over 50,000 UK Biobank and All of Us participants with EHR and identified clinically relevant genetic predictors for improved personalized treatment strategies.

Predictive Value of SLCO1B1 c.521T>C Polymorphism on Observed Changes in the Treatment of 1136 Statin-Users

Pharmacogenomic testing is a method to prevent adverse drug reactions. Pharmacogenomics could be relevant to optimize statin treatment, by identifying patients at high risk for adverse drug reactions. We aim to investigate the clinical validity and utility of pre-emptive pharmacogenomics screening in primary care, with SLCO1B1 c.521T>C as a risk factor for statin-induced adverse drug reactions. The focus was on changes in therapy as a proxy for adverse drug reactions observed in statin-users in a population-based Dutch cohort. In total, 1136 statin users were retrospectively genotyped for the SLCO1B1 c.521T>C polymorphism (rs4149056) and information on their statin dispensing was evaluated as cross-sectional research. Approximately half of the included participants discontinued or switched their statin treatment within three years. In our analyses, we could not confirm an association between the SLCO1B1 c.521T>C genotype and any change in statin therapy or arriving at a stable dose sooner in primary care. To be able to evaluate the predictive values of SLCO1B1 c.521T>C genotype on adverse drug reactions from statins, prospective data collection of actual adverse drug reactions and reasons to change statin treatment should be facilitated.

Immune-Mediated Necrotizing Myopathy Manifesting after Five Years of Statin Therapy

Immune-mediated necrotizing myopathy (IMNM) is an increasingly common and serious condition in which autoantibodies attack muscle fibers causing clinically significant muscle weakness, fatigue, and myalgias. Recognizing the clinical presentation of IMNM is difficult but necessary, as rapid intervention decreases morbidity. We present a case of a 53-year-old female with IMNM induced by statin therapy with confirmed anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibodies present on serologic testing. The patient's statin therapy was halted, and the patient was provided with one dose of methylprednisolone and ongoing therapy with mycophenolate. She showed subsequent slow improvements in her muscle weakness and myalgias. It is important for clinicians to be aware of the possible consequences of statin therapy, as these drugs are generally regarded as benign in the medical community. Clinicians should also be aware that statin-induced myopathy can occur at any time during statin therapy. The condition does not necessarily correlate with beginning a new statin medication, as demonstrated in this case in which the patient was on chronic statin therapy before developing symptoms. Continued clinician education and building the fund of medical knowledge regarding this disease are vital to enable clinicians to recognize this disease and act promptly to reduce patient morbidity and improve outcomes.

Statin-associated immune-mediated necrotizing myositis in Native Americans

OBJECTIVES

Statin-associated immune-mediated necrotizing myopathy (IMNM) and idiopathic inflammatory myositis (IIM) are myopathies with overlapping features. This study compared the manifestations of IMNM to IIM in Native Americans.

METHOD

Twenty-one Native American patients with inflammatory myopathy (IM) were characterized as to diabetes mellitus, hyperlipidaemia, statin exposure, myopathy diagnosis, muscle histology, autoimmune and myositis-specific autoantibodies, therapy and outcome.

RESULTS

IM consisted of 52.4% IMNM, 42.9% IIM and 4.8% metabolic myopathy. IMNM vs IIM patients were older [61.6 years (s.d. 9.8) vs 39.8 (14.3)], diabetes mellitus (100% vs 55.6%), hyperlipidaemia (100% vs 33.3%), statin-exposure (100% vs 22.2%), creatine kinase [CK; 11 780 IU (s.d. 7064) vs 1707 (1658)], anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) antibodies (85.7% vs 11.1%) and necrotizing IM (81.8% vs 11.1%), but shorter disease duration [26.2 months (s.d. 395) vs 78.4 (47.9)], RP (9.1% vs 55.6%), cutaneous manifestations (0% vs 55.6%), ANA (18.2% vs 66.7%) or any autoantibody (18.2% vs 88.9%) (all P < 0.05). MRI abnormalities, histologic IM, myositis-specific autoantibodies, pulmonary hypertension, oesophageal dysfunction, interstitial lung disease, disability and persistently elevated CK were similar. IMNM vs IIM was treated more with IVIG (72.7% vs 11.1%; P = 0.009) and less with antimetabolites (45.5% vs 88.9%; P = 0.05) and rituximab (18.2% vs 55.6%; P = 0.09).

CONCLUSIONS

IMNM may occur in Native Americans and is associated with diabetes mellitus, hyperlipidaemia, statin use and older age and is characterized by marked CK elevation, necrotizing myopathy and anti-HMGCR antibodies with few cutaneous or vascular manifestations.

SLCO1B1 and ABCB1 variants synergistically influence the atorvastatin treatment response in south Indian coronary artery disease patients

Introduction: Atorvastatin exhibits wide interindividual variability in treatment response, limiting the drug efficacy in coronary artery disease patients. Aim: To study the effect of genetic variants involved in atorvastatin transport/metabolism and correlate their lipid-lowering efficacy. Materials & methods: Genotyping was performed using 5'-hydrolysis probe method (n = 412), and the study evaluated the treatment response in 86 patients. Results: Significant reduction in total cholesterol and low-density lipoprotein cholesterol (LDL-C) were observed in SLCO1B1-rs4149056, rs4363657 and ABCB1-rs1045642 genotypes. The combined genotypes of ABCB1 and SLCO1B1 showed a strong synergistic effect in reducing the total cholesterol and LDL-C. Diabetes and smoking were observed to influence the LDL-C reduction. Conclusion: The genetic variants of SLCO1B1 and ABCB1 predict the lipid-lowering efficacy of atorvastatin, and this may be useful in genotype-guided statin therapy for coronary artery disease patients.

Step-by-step diagnosis and management of the nocebo/drucebo effect in statin-associated muscle symptoms patients: a position paper from the International Lipid Expert Panel (ILEP)

Statin intolerance is a clinical syndrome whereby adverse effects (AEs) associated with statin therapy [most commonly statin-associated muscle symptoms (SAMS)] result in the discontinuation of therapy and consequently increase the risk of adverse cardiovascular outcomes. However, complete statin intolerance occurs in only a small minority of treated patients (estimated prevalence of only 3-5%). Many perceived AEs are misattributed (e.g. physical musculoskeletal injury and inflammatory myopathies), and subjective symptoms occur as a result of the fact that patients expect them to do so when taking medicines (the nocebo/drucebo effect)-what might be truth even for over 50% of all patients with muscle weakness/pain. Clear guidance is necessary to enable the optimal management of plasma in real-world clinical practice in patients who experience subjective AEs. In this Position Paper of the International Lipid Expert Panel (ILEP), we present a step-by-step patient-centred approach to the identification and management of SAMS with a particular focus on strategies to prevent and manage the nocebo/drucebo effect and to improve long-term compliance with lipid-lowering therapy.

Statin-Induced Myopathy: Translational Studies from Preclinical to Clinical Evidence

Statins are the most prescribed and effective drugs to treat cardiovascular diseases (CVD). Nevertheless, these drugs can be responsible for skeletal muscle toxicity which leads to reduced compliance. The discontinuation of therapy increases the incidence of CVD. Thus, it is essential to assess the risk. In fact, many studies have been performed at preclinical and clinical level to investigate pathophysiological mechanisms and clinical implications of statin myotoxicity. Consequently, new toxicological aspects and new biomarkers have arisen. Indeed, these drugs may affect gene transcription and ion transport and contribute to muscle function impairment. Identifying a marker of toxicity is important to prevent or to cure statin induced myopathy while assuring the right therapy for hypercholesterolemia and counteracting CVD. In this review we focused on the mechanisms of muscle damage discovered in preclinical and clinical studies and highlighted the pathological situations in which statin therapy should be avoided. In this context, preventive or substitutive therapies should also be evaluated.

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.

Detection of Anti-mitochondrial Antibodies Accompanied by Drug-induced Hepatic Injury due to Atorvastatin

A 44-year-old Japanese woman was admitted to our hospital with fatigue and an altered liver function. She had been receiving atorvastatin treatment for 10 months. Although no jaundice was seen, the patient's serum alkaline phosphatase and γ-glutamyl transpeptidase levels were markedly elevated. Based on the results of a drug-induced lymphocyte-stimulation test, her liver disease was diagnosed as atorvastatin-induced hepatic injury. Subsequently, anti-mitochondrial antibodies (AMAs) were detected in her serum; however, a liver biopsy specimen did not show the characteristic features of primary biliary cholangitis. We herein report the detection of AMAs accompanied by drug-induced hepatic injury caused by atorvastatin.

Evidence to Support Inclusion of Pharmacogenetic Biomarkers in Randomised Controlled Trials

Pharmacogenetics and biomarkers are becoming normalised as important technologies to improve drug efficacy rates, reduce the incidence of adverse drug reactions, and make informed choices for targeted therapies. However, their wider clinical implementation has been limited by a lack of robust evidence. Suitable evidence is required before a biomarker’s clinical use, and also before its use in a clinical trial. We have undertaken a review of five pharmacogenetic biomarker-guided randomised controlled trials (RCTs) and evaluated the evidence used by these trials to justify biomarker inclusion. We assessed and quantified the evidence cited in published rationale papers, or where these were not available, obtained protocols from trial authors. Very different levels of evidence were provided by the trials. We used these observations to write recommendations for future justifications of biomarker use in RCTs and encourage regulatory authorities to write clear guidelines.

Statin-induced muscular side effects at rest and exercise - An anatomical mapping

BACKGROUND AND AIMS

Muscle-related symptoms with or without creatine kinase (CK) elevation are common adverse effects associated with statin use. Symptoms are ranging from benign myalgia to myositis and in rare cases to rhabdomyolysis. The aim was to characterize and describe muscular side effects and create an anatomical frequency mapping.

METHODS

The prospective observational study was performed at a large lipidology outpatient unit in Vienna. 1111 consecutively admitted patients with muscular side effects on statin monotherapy were included during a 4-year period. Anatomical mapping of the affected muscles, signs and symptoms, the onset of symptoms after starting statin therapy and disappearance after cessation of treatment was assessed.

RESULTS

In 96.5% of the patients with muscle symptoms, there was no elevation of CK. The anatomical mapping revealed exercised muscles as being mainly affected in 84%. In the upper extremity, symptoms were mainly described at the dominating side. Mostly affected muscles were the pectoral (61.4%), followed by the quadriceps femoris (59.8%), the biceps brachii (54.3%) and the deltoid (22.5%) muscles. The majority of symptoms (76.9%, n = 854) appeared within 29 days. Symptoms disappeared after discontinuation of statin therapy at a mean of 5.4 days.

CONCLUSIONS

Physical activity seems to be a key trigger for onset of statin-induced muscular side effects. The appearance of symptoms can be symmetrical, asymmetrical, generalized or in isolated muscle groups only. Different statins usually produce similar symptoms, but often some patients tolerate one statin better than another.

A comprehensive review and meta-analysis of risk factors for statin-induced myopathy

PURPOSE

To aid prescribers in assessing a patient's risk for statin-induced myopathy (SIM), we performed a comprehensive review of currently known risk factors and calculated aggregated odds ratios for each risk factor through a meta-analysis.

METHODS

This meta-analysis was done through four phases: (1) Identification of the relevant primary literature; (2) abstract screening using inclusion and exclusion criteria; (3) detailed review and data extraction; and (4) synthesis and statistical analysis.

RESULTS

Out of 44 papers analyzed from 836 papers searched from MEDLINE, 18 different potential risk factors were collected, divided into three categories: three demographics (11 papers), ten clinical factors (31 papers), and five pharmacogenetics/biomarkers (12 papers). Risk factors significant for myopathy and/or rhabdomyolysis included age, gender, diabetes, renal impairment, cardiovascular disease, certain interacting drugs, and mutations of the SLCO1B1 gene, which encodes a transporter protein in the liver. Several factors, such as gender, race, cardiovascular disease, and the GATM gene, which encodes a protein for creatine synthesis, appeared to be protective in terms of the outcomes of interest.

CONCLUSIONS

This comprehensive assessment of risk factors can help support clinicians in reducing the incidence of SIM in their patient population on statins.

Statin-induced myalgia and myositis: an update on pathogenesis and clinical recommendations

INTRODUCTION

Musculoskeletal manifestations are well-recognized side effects of treatment with statins. New advances in this field have appeared in recent years. This review focuses on the diagnosis of these conditions and their underlying pathogenesis, in particular immune-mediated necrotizing myopathy. Areas covered: Clinical phenotypes including rhabdomyolysis, myalgia and/or mild hyperCKemia, self-limited toxin statin myopathy, and immune-mediated necrotizing myopathy are herein described. Therapeutic recommendations and a diagnostic algorithm in statin-associated myopathy are also proposed. The etiology and pathogenesis of statin-induced myopathy has mainly focused on the anti-HMGCR antibodies and the responsibility of the immune-mediated necrotizing myopathy is discussed. The fact that patients who have not been exposed to statins may develop statin-associated autoimmune myopathy with anti-HMGCR antibodies is also addressed. The literature search strategy included terms identified by searches of PubMed between 1969 and December 2017. The search terms 'myositis', 'statin-induced autoimmune myopathy', 'immune-mediate necrotizing myopathy', 'statins', 'muscular manifestations', and 'anti-HMGCR antibodies' were used. Expert commentary: Full characterization of the known phenotypes of statin toxicity and the specific role of the anti-HMGCR in those exposed and not exposed (i.e. juvenile forms) to statins and in some types of neoplasms is of paramount relevance.

Pharmacogenetics: a general review on progress to date

BACKGROUND

Pharmacogenetics is not a new subject area but its relevance to drug prescribing has become clearer in recent years due to developments in gene cloning and DNA genotyping and sequencing.

SOURCES OF DATA

There is a very extensive published literature concerned with a variety of different genes and drugs.

AREAS OF AGREEMENT

There is general agreement that pharmacogenetic testing is essential for the safe use of drugs such as the thiopurines and abacavir.

AREAS OF CONTROVERSY

Whether pharmacogenetic testing should be applied more widely including to the prescription of certain drugs such as warfarin and clopidogrel where the overall benefit is less clear remains controversial.

GROWING POINTS

Personal genotype information is increasingly being made available directly to the consumer. This is likely to increase demand for personalized prescription and mean that prescribers need to take pharmacogenetic information into account. Projects such as 100 000 genomes are providing complete genome sequences that can form part of a patient medical record. This information will be of great value in personalized prescribing.

AREAS TIMELY FOR DEVELOPING RESEARCH

Development of new drugs targeting particular genetic risk factors for disease. These could be prescribed to those with an at risk genotype.

Statin-associated muscle symptoms: position paper from the Luso-Latin American Consortium

In the last two decades, statin therapy has proved to be the most potent isolated therapy for attenuation of cardiovascular risk. Its frequent use has been seen as one of the most important elements for the reduction of cardiovascular mortality in developed countries. However, the recurrent incidence of muscle symptoms in statin users raised the possibility of causal association, leading to a disease entity known as statin associated muscle symptoms (SAMS). Mechanistic studies and clinical trials, specifically designed for the study of SAMS have allowed a deeper understanding of the natural history and accurate incidence. This set of information becomes essential to avoid an unnecessary risk of severe forms of SAMS. At the same time, this concrete understanding of SAMS prevents overdiagnosis and an inadequate suspension of one of the most powerful prevention strategies of our times. In this context, the Luso-Latin American Consortium gathered all available information on the subject and presents them in detail in this document as the basis for the identification and management of SAMS.

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.

Statin-associated muscle symptoms and SLCO1B1 rs4149056 genotype in patients with familial hypercholesterolemia

Patients with familial hypercholesterolemia (FH) may be at increased risk for statin-associated muscle symptoms because they require long-term treatment with high-intensity statin therapy. We sought to determine (1) whether other predisposing factors, including the well-known genetic variant associated with statin-associated muscle symptoms-solute carrier organic anion transporter family, member 1B1 (SLCO1B1) rs4149056-also increase the risk of statin-associated muscle symptoms in FH patients, and (2) the natural history and management for FH patients with statin-associated muscle symptoms.

METHODS

We queried electronic records (2004-2014) of 278 genetically screened FH patients (113 men, 165 women; mean [SD] pretreatment low-density lipoprotein cholesterol [LDL-C] 259 [72] mg/dL) recruited from lipid clinics in the Dallas, TX, area from 2004 to 2014. Statin-associated muscle symptoms were defined as muscle symptoms arising while taking a statin and interrupting therapy.

RESULTS

The risk of muscle symptoms was associated with age (odds ratio 1.6 [95% CI 1.2-2.2]), body mass index in non-African Americans (0.90 [0.83-0.97]), and hypertension (0.4 [0.2-0.9]). Simvastatin was the most commonly used statin, and it was the statin most associated with muscle symptoms. Among FH patients with muscle symptoms, 41% (n = 40) reestablished statin therapy ("eventually tolerant") and 29% (n = 28) never reestablished statin therapy ("never tolerant"). Rosuvastatin (43%) and pravastatin (30%) were the most common eventually tolerated statins, and eventually tolerant patients achieved lower treated LDL-C levels (eventually tolerant 127 vs never tolerant 192 mg/dL, P < .001). Never tolerant patients also developed muscle symptoms on nonstatins (16% vs 50%, P = .003). SLCO1B1 rs4149056 genotyping revealed 224 wild-type patients (TT) and 49 heterozygotes (TC). SLCO1B1 genotype was not associated with the risk of statin-associated muscle symptoms (odds ratio 1.40 [95% CI 0.74-2.64]).

CONCLUSION

Age, not SLCO1B1 rs4149056 genotype, was the strongest risk factor for statin-associated muscle symptoms in FH patients. After developing muscle symptoms, many patients reestablished statin therapy and achieved significant LDL-C reductions. Overall, 10% of all FH patients had statin-associated muscle symptoms and never reestablished statin therapy. Such patients developed muscle symptoms even on nonstatin lipid-lowering drugs and continued to have elevations in LDL-C. Further insight is needed into the relationship between FH and statin-associated muscle symptoms so all FH patients can be adequately treated.

Association of Statins with Sensory and Autonomic Ganglionopathy

Objective

To examine if statins have an effect on small nerve fibers.

Methods

This retrospective study evaluated the effect of statins in pure small-fiber neuropathy (SFN). Outcome measures were symptom scales (numbness, tingling, and autonomic symptoms), skin biopsies assessing epidermal nerve fiber density (ENFD), sweat gland nerve fiber density (SGNFD), and quantitative autonomic testing.

Results

One hundred and sixty participants with pure SFN were identified. Eighty participants (women/men, age ± SD 33/47, 68.1 ± 11.6 years old) were on statins for 53.5 ± 28.7 months to treat dyslipidemia and they were age and gender matched with 80 participants (33/47, 68.1 ± 9.5) that were off statins. ANOVA showed reduced ENFD/SGNFD at the proximal leg in the statin group [(count/mm) 8.3 ± 3.6/51.3 ± 14.2] compared to the off statin group (10.4 ± 3.8, p = 0.0008/56.4 ± 12.7, p = 0.018). There was no difference in ENFD/SGNFD at the distal leg in the statin group (4.9 ± 3.2/39.8 ± 15.7) compared to the off statin group (5.9 ± 3.4, p = 0.067/41.8 ± 15.9, p = 0.426). Statins did not affect symptom scales and the outcome of autonomic testing.

Conclusion

Statin use is associated with degeneration of sensory and autonomic fibers. The pattern of abnormalities, e.g., degeneration of proximal while sparing of distal fibers, is consistent with a non-length-dependent process with lesions in the dorsal root and the autonomic ganglia. The statin-associated sensory and autonomic ganglionopathy is mild.