Long-term follow-up of 62 patients with myositis

Autoantibodies and damage in patients with idiopathic inflammatory myopathies: A longitudinal multicenter study from the MYONET international network

OBJECTIVE

To study the trajectories of changes in damage over time and explore associations with autoantibody defined subgroups using a large international cohort of patients with idiopathic inflammatory myopathies (IIM).

METHODS

Data from the MYONET registry, including patients who were tested for autoantibodies and had at least one assessment of damage using the Myositis Damage Index (MDI), were analyzed. Patients were sub-grouped according to their autoantibody profiles (myositis-specific, myositis-associated, or seronegative). The index date was defined as the time point for the first registered MDI assessment. The longitudinal trajectories of damage with autoantibody status as the main predictor were analyzed using linear mixed models.

RESULTS

A total of 757 adult patients were included in this study. Each year of disease duration since diagnosis had an estimated MDI score increase of 0.16 units for the seronegative group (reference). Compared with the seronegative group as reference, patients with dermatomyositis-specific autoantibodies developed less damage per year of follow-up since diagnosis (average 0.08 less score, P = 0.04), whereas patients with anti-PM/Scl autoantibodies developed more damage per year of follow-up since diagnosis (average 0.28 higher score, P = 0.03) independent of sex and age at diagnosis. The seronegative subgroup and the immune-mediated necrotizing myopathy autoantibody subgroup had the strongest correlation between severity of muscle damage and HAQ-DI scores at five years of follow-up, rho=0.84, P < 0.001 and rho=0.72, P < 0.001, respectively.

CONCLUSION

Our study is the first to describe patterns and trajectories of change in damage over time in relation to autoantibody defined subgroups in a large international multicenter cohort of patients with IIM. Patients with anti-PM/Scl scored a greater extent of damage, whereas patients with dermatomyositis-specific antibodies had less damage than seronegative patients. Severity in muscle damage had moderate to strong correlation with functional disability among the IMNM and seronegative subgroups with lower correlations for the other subgroups. These findings suggest that autoantibodies may be useful predictors of long-term damage.

High-intensity resistance training improves quality of life, muscle endurance and strength in patients with myositis: a randomised controlled trial

Myositis is associated with reduced quality of life, which is accompanied by significant impairments in muscle endurance and strength, altogether representing cardinal traits in patients with myositis. This randomised controlled trial aimed to investigate the effect of high-intensity resistance training on quality of life in patients with myositis. Thirty-two patients with established, stable myositis were randomised to 16 weeks of high-intensity resistance training (intervention group) or 16 weeks of usual care (control group). Primary outcome was quality of life assessed as the change in the physical component summary score (PCS) of the Short Form-36 health questionnaire from baseline to post-intervention. Secondary outcomes included functional capacity measures, such as functional index 3, and International Myositis Assessment and Clinical Studies Group (IMACS) disease activity and damage core set measures, including manual muscle testing 8 (MMT8). The primary outcome PCS showed an improvement in favour of high-intensity resistance training with a between-group difference of 5.33 (95% CI 0.61; 10.05) (p = 0.03). Additionally, functional index 3 showed a between-group difference indicating greater gains with high-intensity resistance training 11.49 (95% CI 3.37; 19.60) (p = 0.04), along with a between-group improvement in MMT8 1.30 (95% CI 0.09; 2.51) (p = 0.04). High-intensity resistance training for 16 weeks effectively improved quality of life in patients with myositis. Clinical measures of muscle endurance and muscle strength were also found to improve with high-intensity resistance training, while patients stayed in disease remission. Consequently, progressively adjusted high-intensity resistance training is feasible and causes no aggravation of the disease, while benefitting patients with myositis.Clinical trial registration: Clinicaltrials.gov ID: NCT04486261- https://clinicaltrials.gov/study/NCT04486261 .

The impact of pain on daily activities in patients with idiopathic inflammatory myopathies: Report from the OMERACT myositis working group

BACKGROUND

International focus groups with patients with idiopathic inflammatory myopathies (IIM) conducted by the OMERACT Myositis Working Group over the years demonstrated the pain as an important symptom experienced by these patients. In this study, we aimed to examine the frequency and degree of pain interference, the aspects of daily life impacted by pain, and the factors associated with pain interference in adults with IIM.

METHODS

This was a prospective observational study with two visits. The patients who fulfilled the probable/definite IIM (ACR/EULAR Myositis Classification Criteria) were enrolled. Pain interference was assessed with PROMIS pain interference form (6a). Myositis core set measures and PROMIS fatigue (7a) and physical function (8b) were obtained at both visits. Logistic regression and linear mixed models were performed to assess the association between pain interference and other parameters.

RESULTS

A total of 129 patients with IIM (60 % females) were recruited from U.S., South Korea, Netherlands, Sweden, and Australia. Approximately 71 % reported pain interference. The patients in the greater pain interference group were more likely to be female, had significantly worse patient/physician global disease activity, fatigue, and physical function than those in the lower pain interference group. The most commonly impacted life aspect was household chores. Manual muscle testing, patient/physician global disease activity, fatigue, and physical function were all significantly associated with pain interference score >60.

CONCLUSION

The majority of the patients with IIM experience the impact of pain on their daily activities, particularly household chores. Myositis disease activity, duration, and subtype could be associated with greater pain interference.

Direct and indirect costs of idiopathic inflammatory myopathies in adults: A systematic review

Idiopathic inflammatory myopathies (IIMs) are rare disorders characterized by inflammation of skeletal muscle, which can result in fatty replacement of muscle, muscle atrophy, and subsequent weakness. Therapeutic advancements have improved clinical outcomes but impose an economic impact on healthcare systems. We aimed to summarize the direct and indirect costs associated with IIMs in a systematic review (PROSPERO Registration #CRD42023443143). Electronic databases (MEDLINE, Embase, CINAHL, and Scopus) were systematically searched for full-length articles (excluding case reports) reporting costs specific to patients diagnosed with an IIM, published between database inception and April 19, 2023. Direct cost categories included inpatient, outpatient, medication, home/long-term care, and durable medical equipment such as mobility and respiratory aids. Indirect costs included lost productivity. Eligibility criteria were met by 21 of the 3,193 unique titles identified. Costs are expressed in 2023 United States of America dollars, with adjustments for differences in purchasing power applied to currency conversions. As no study reported on all cost categories, annualized cost of IIM per patient was estimated by calculating the mean cost per category, and then adding the means of the different cost categories. By this method, IIM was estimated to cost $52,210 per patient per year. Proportional contributions by category were lost productivity (0.278), outpatient care (0.214), medications (0.171), inpatient care (0.161), home/long-term care (0.122), and durable medical equipment (0.053). Newer findings with intravenous immunoglobulin considered first line therapy for IIM demonstrated markedly higher annual medication costs per patient, upwards of $33,900 compared to an average of $3,908 ± $1,042 in older studies. Future cost-effectiveness studies require updated cost-of-illness studies reflecting the evolving sub-classification and treatment options for IIM, and should consider the impact of IIM on patients and their families.

The Role of Exercise to Improve Physiological, Physical and Psychological Health Outcome in Idiopathic Inflammatory Myopathies (IIM)

Idiopathic inflammatory myopathies (IIM) impact all aspects of health, physiological, physical, and psychological. Hallmark symptoms of IIM are muscle weakness, reduced muscle endurance and aerobic capacity. Recently, pain and fatigue as well as anxiety and depression have emerged as common and debilitating symptoms in patients with IIM. The aim of this scoping review is to, in a holistic way, describe how IIM impact patients' physiological, physical, and psychological health and how exercise has a role to treat as well as potentially counteract the effects of the disease. Inflammation induces non-immune response and organ damage. These changes with additional impact of physical inactivity lead to muscle impairment and reduced aerobic capacity. Pain, fatigue and low psychological well-being and overall quality of life are also common health aspects of IIM. Medical treatment can reduce inflammation but has in turn serious side effects such as muscle atrophy, type-II diabetes, and hypertension, which exercise has the potential to treat, and perhaps also counteract. In addition, exercise improves muscle function, aerobic capacity and might also reduce fatigue and pain. New evidence shows that reducing systemic inflammation may also improve patient-reported subjective health, quality of life and psychological well-being. Exercise in combination with medical treatment is becoming an important part of the treatment for patients with IIM as exercise has the potential to promote health aspects of various dimensions in patients with IIM.

Pathogenic role and clinical significance of neutrophils and neutrophil extracellular traps in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of chronic autoimmune diseases characterized by muscle damage and extramuscular symptoms, including specific skin rash, arthritis, interstitial lung disease, and cardiac involvement. While the etiology and pathogenesis of IIM are not yet fully understood, emerging evidence suggests that neutrophils and neutrophil extracellular traps (NETs) have a role in the pathogenesis. Recent research has identified increased levels of circulating and tissue neutrophils as well as NETs in patients with IIM; these contribute to the activation of the type I and type II interferons pathway. During active IIM disease, myositis-specific antibodies are associated with the formation and incomplete degradation of NETs, leading to damage in the lungs, muscles, and blood vessels of patients. This review focuses on the pathogenic role and clinical significance of neutrophils and NETs in IIM, and it includes a discussion of potential targeted treatment strategies.

Impaired health-related quality of life in idiopathic inflammatory myopathies: a cross-sectional analysis from the COVAD-2 e-survey

Objectives

To investigate health-related quality of life in patients with idiopathic inflammatory myopathies (IIMs) compared with those with non-IIM autoimmune rheumatic diseases (AIRDs), non-rheumatic autoimmune diseases (nrAIDs) and without autoimmune diseases (controls) using Patient-Reported Outcome Measurement Information System (PROMIS) instrument data obtained from the second COVID-19 vaccination in autoimmune disease (COVAD-2) e-survey database.

Methods

Demographics, diagnosis, comorbidities, disease activity, treatments and PROMIS instrument data were analysed. Primary outcomes were PROMIS Global Physical Health (GPH) and Global Mental Health (GMH) scores. Factors affecting GPH and GMH scores in IIMs were identified using multivariable regression analysis.

Results

We analysed responses from 1582 IIM, 4700 non-IIM AIRD and 545 nrAID patients and 3675 controls gathered through 23 May 2022. The median GPH scores were the lowest in IIM and non-IIM AIRD patients {13 [interquartile range (IQR) 10-15] IIMs vs 13 [11-15] non-IIM AIRDs vs 15 [13-17] nrAIDs vs 17 [15-18] controls, P < 0.001}. The median GMH scores in IIM patients were also significantly lower compared with those without autoimmune diseases [13 (IQR 10-15) IIMs vs 15 (13-17) controls, P < 0.001]. Inclusion body myositis, comorbidities, active disease and glucocorticoid use were the determinants of lower GPH scores, whereas overlap myositis, interstitial lung disease, depression, active disease, lower PROMIS Physical Function 10a and higher PROMIS Fatigue 4a scores were associated with lower GMH scores in IIM patients.

Conclusion

Both physical and mental health are significantly impaired in IIM patients, particularly in those with comorbidities and increased fatigue, emphasizing the importance of patient-reported experiences and optimized multidisciplinary care to enhance well-being in people with IIMs.

TCRβ clones in muscle tissue share structural features in patients with idiopathic inflammatory myopathy and are associated with disease activity

Objectives

To characterize the T cell receptor (TCRβ) repertoire in peripheral blood and muscle tissues of treatment naïve patients with newly diagnosed idiopathic inflammatory myopathies (IIMs).

Methods

High throughput RNA sequencing of the TCRβ chain was performed in peripheral blood and muscle tissue in twenty newly-diagnosed treatment-naïve IIM patients (9 DM, 5 NM/OM, 5 IMNM and 1 ASyS) and healthy controls. Results thereof were correlated with markers of disease activity.

Results

Muscle tissue of IIM patients shows more expansion of TCRβ clones and decreased diversity when compared to peripheral blood of IIM as well as healthy controls (both p=0.0001). Several expanded TCRβ clones in muscle are tissue restricted and cannot be retrieved in peripheral blood. These clones have significantly longer CDR3 regions when compared to clones (also) found in circulation (p=0.0002), while their CDR3 region is more hydrophobic (p<0.01). Network analysis shows that clonal TCRβ signatures are shared between patients. Increased clonal expansion in muscle tissue is significantly correlated with increased CK levels (p=0.03), while it tends to correlate with decreased muscle strength (p=0.08).

Conclusion

Network analysis of clones in muscle of IIM patients shows shared clusters of sequences across patients. Muscle-restricted CDR3 TCRβ clones show specific structural features in their T cell receptor. Our results indicate that clonal TCRβ expansion in muscle tissue might be associated with disease activity. Collectively, these findings support a role for specific clonal T cell responses in muscle tissue in the pathogenesis of the IIM subtypes studied.

Glucagon-Like Peptide-1 Receptor Agonists in the Treatment of Idiopathic Inflammatory Myopathy: From Mechanisms of Action to Clinical Applications

Idiopathic inflammatory myopathies (IIMs) result in proximal muscle weakness and other intramuscular and extramuscular manifestations. Pharmacologic treatments in use for IIMs are limited to corticosteroids and immunosuppressants in addition to supportive physical and occupational therapy. Glucagon-like peptide-1 receptor (GLP-1R) agonists are currently utilized in the treatment of type II diabetes and obesity but may play a role in the treatment of IIMs. The current scoping review of extant literature aims to synthesize findings from studies assessing the therapeutic effects of GLP-1R agonists in the management of inflammatory myopathy and muscle atrophy. A literature search was conducted through PubMed, resulting in a total of 19 research-based articles included in this review. Mice and human studies showed, with varying levels of significance, that GLP-1R agonists led to decreases in muscle atrophy, inflammation, adiposity, and weakness; improvement in muscle microvasculature and endurance; and promotion of muscle mitochondria biogenesis. The potential for GLP-1R agonists to improve muscle function and architecture underscores the need for large randomized controlled, clinically comparative trials of GLP-1R agonists in patients with IIM.

Discordance between patient- and physician-reported disease activity in adult idiopathic inflammatory myopathy

OBJECTIVES

Patient-reported global disease activity (patient-global) is a myositis core set measure. Understanding the drivers of patient-global is important in patient assessment, and disagreements between physician and patient perception of disease activity may negatively impact shared decision making. We examined the determinants of patient-global and discordance between patient-global and physician-reported global disease activity (physician-global) in idiopathic inflammatory myopathies (IIMs).

METHODS

Adults with IIM were enrolled in a prospective observational cross-sectional study. The following myositis outcome measures were collected: patient-global, physician-global, extramuscular and muscle disease activity, manual muscle testing, HAQ, creatine kinase, fatigue, pain, Patient-Reported Outcomes Measurement Information System physical function, 36-item Short Form, sit to stand, timed up and go, 6-minute walk and Actigraph steps/min/day count. A linear regression model was used to determine the contribution of each measure to patient-global. Discordance was defined as ≥3 points difference between patient-global and physician-global.

RESULTS

Fifty patients [60% females; mean age 51.6 years (s.d. 14.9)] with probable/definite IIM (EULAR/ACR classification criteria for IIM) were enrolled. Physical function and fatigue measures contributed to patient-global the most, followed by measures of pain, physical activity, quality of life and muscle disease, while physician-global was primarily driven by muscle disease activity. Patient-global was discordant with physician-global in 30% of the patients, of which patient-global was higher than physician-global in 66%. Pain, fatigue and physical activity contributed more to patient-global than physician-global.

CONCLUSION

Fatigue, pain and physical activity are important driving factors of the differences observed in the patient vs physician assessment of myositis disease activity. Understanding the gap between patient and physician perspectives may help provide better patient-centred care.

Epidemiology of the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic autoimmune diseases that affect the skeletal muscles and can also involve the skin, joints, lungs and heart. The epidemiology of IIM is obscured by changing classification criteria and the inherent shortcomings of case identification using healthcare record diagnostic coding. The incidence of IIM is estimated to range from 0.2 to 2 per 100,000 person-years, with prevalence from 2 to 25 per 100,000 people. Although the effects of age and gender on incidence are known, there is only sparse understanding of ethnic differences, particularly in indigenous populations. The incidence of IIM has reportedly increased in the twenty-first century, but whether this is a genuine increase is not yet known. Understanding of the genetic risk factors for different IIM subtypes has advanced considerably. Infections, medications, malignancy and geography are also commonly identified risk factors. Potentially, the COVID-19 pandemic has altered IIM incidence, although evidence of this occurrence is limited to case reports and small case series. Consideration of the current understanding of the epidemiology of IIM can highlight important areas of interest for future research into these rare diseases.

255th ENMC workshop: Muscle imaging in idiopathic inflammatory myopathies. 15th January, 16th January and 22nd January 2021 - virtual meeting and hybrid meeting on 9th and 19th September 2022 in Hoofddorp, The Netherlands

The 255th ENMC workshop on Muscle Imaging in Idiopathic Inflammatory myopathies (IIM) aimed at defining recommendations concerning the applicability of muscle imaging in IIM. The workshop comprised of clinicians, researchers and people living with myositis. We aimed to achieve consensus on the following topics: a standardized protocol for the evaluation of muscle images in various types of IIMs; the exact parameters, anatomical localizations and magnetic resonance imaging (MRI) techniques; ultrasound as assessment tool in IIM; assessment methods; the pattern of muscle involvement in IIM subtypes; the application of MRI as biomarker in follow-up studies and clinical trials, and the place of MRI in the evaluation of swallowing difficulty and cardiac manifestations. The following recommendations were formulated: In patients with suspected IIM, muscle imaging is highly recommended to be part of the initial diagnostic workup and baseline assessment. MRI is the preferred imaging modality due to its sensitivity to both oedema and fat accumulation. Ultrasound may be used for suspected IBM. Repeat imaging should be considered if patients do not respond to treatment, if there is ongoing diagnostic uncertainty or there is clinical or laboratory evidence of disease relapse. Quantitative MRI is established as a sensitive biomarker in IBM and could be included as a primary or secondary outcome measure in early phase clinical trials, or as a secondary outcome measure in late phase clinical trials. Finally, a research agenda was drawn up.

High fatigue scores in patients with idiopathic inflammatory myopathies: a multigroup comparative study from the COVAD e-survey

Idiopathic inflammatory myopathies (IIMs) confer a significant risk of disability and poor quality of life, though fatigue, an important contributing factor, remains under-reported in these individuals. We aimed to compare and analyze differences in visual analog scale (VAS) scores (0-10 cm) for fatigue (VAS-F) in patients with IIMs, non-IIM systemic autoimmune diseases (SAIDs), and healthy controls (HCs). We performed a cross-sectional analysis of the data from the COVID-19 Vaccination in Autoimmune Diseases (COVAD) international patient self-reported e-survey. The COVAD survey was circulated from December 2020 to August 2021, and details including demographics, COVID-19 history, vaccination details, SAID details, global health, and functional status were collected from adult patients having received at least one COVID-19 vaccine dose. Fatigue experienced 1 week prior to survey completion was assessed using a single-item 10 cm VAS. Determinants of fatigue were analyzed in regression models. Six thousand nine hundred and eighty-eight respondents (mean age 43.8 years, 72% female; 55% White) were included in the analysis. The overall VAS-F score was 3 (IQR 1-6). Patients with IIMs had similar fatigue scores (5, IQR 3-7) to non-IIM SAIDs [5 (IQR 2-7)], but higher compared to HCs (2, IQR 1-5; P < 0.001), regardless of disease activity. In adjusted analysis, higher VAS-F scores were seen in females (reference female; coefficient -0.17; 95%CI -0.21 to -13; P < 0.001) and Caucasians (reference Caucasians; coefficient -0.22; 95%CI -0.30 to -0.14; P < 0.001 for Asians and coefficient -0.08; 95%CI -0.13 to 0.30; P = 0.003 for Hispanics) in our cohort. Our study found that patients with IIMs exhibit considerable fatigue, similar to other SAIDs and higher than healthy individuals. Women and Caucasians experience greater fatigue scores, allowing identification of stratified groups for optimized multidisciplinary care and improve outcomes such as quality of life.

Treatment with add-on IVIg in Myositis Early In the diSease course May be sUperior to Steroids alone for reaching CLinical improvEment (TIME IS MUSCLE): study protocol of a phase-2 double-blind placebo-controlled randomised trial

INTRODUCTION

For idiopathic inflammatory myopathies (IIM) ('myositis') standard initial treatment is high-dosed glucocorticoids, which results in relatively slow improvement of muscle strength. Early immunosuppression or modulation by intensive treatment ('hit-early, hit-hard') may induce faster reduction of disease activity and prevent chronic disability due to disease-induced structural muscle damage. Intravenous immunoglobulin (IVIg) in addition to standard glucocorticoid treatment may be promising in this regard as was shown in various studies: add-on IVIg improved symptoms and muscle strength in refractory myositis patients and monotherapy IVIg improved outcomes after 9 weeks, in about half of treatment-naive patients.

HYPOTHESIS

We hypothesise that early add-on IVIg leads to a greater clinical response after 12 weeks in patients with newly diagnosed myositis, in comparison to prednisone monotherapy. Second, we expect that early treatment with add-on IVIg leads to a faster time to improvement and sustained positive effects on multiple secondary outcomes.

METHODS

The Time Is Muscle trial is a phase-2 double-blind placebo-controlled randomised trial. Forty-eight patients with IIM will be treated with IVIg or placebo at baseline (within 1 week after diagnosis) and after 4 and 8 weeks, in addition to standard therapy with prednisone. The primary outcome is the Total Improvement Score (TIS) of the myositis response criteria at 12 weeks. At baseline, and after 4, 8, 12, 26 and 52 weeks, relevant secondary outcomes will be assessed, including time to moderate improvement (TIS≥40), mean daily prednisone dosage, physical activity, health-related quality of life, fatigue and MRI muscle imaging parameters.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the medical ethics committee of the Academic Medical Centre, University of Amsterdam, the Netherlands (2020_180; including a first amendment approval at the 12 April 2023; A2020_180_0001). The results will be distributed through conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

EU Clinical trials register (2020-001710-37).

B-cell receptor profiling before and after IVIG monotherapy in newly diagnosed idiopathic inflammatory myopathies

OBJECTIVE

To unravel B-cell receptor (BcR) characteristics in muscle tissues and peripheral blood and gain more insight into BcR repertoire changes in peripheral blood in idiopathic inflammatory myopathies (IIMs), and study how this correlates to the clinical response to IVIG.

METHODS

Nineteen treatment-naive patients with newly diagnosed IIM were prospectively treated with IVIG monotherapy. RNA-based BcR repertoire sequencing was performed in muscle biopsies collected before, and in peripheral blood (PB) collected before and nine weeks after IVIG treatment. Results were correlated to patients' clinical improvement based on the total improvement score (TIS).

RESULTS

Prior to IVIG treatment, BcR clones found in muscle tissue could be retrieved in peripheral blood. Nine weeks after IVIG treatment, new patient-specific dominant BcR clones appeared in peripheral blood while pre-treatment dominant BcR clones disappeared. The cumulative frequency of all dominant BcR clones before treatment was significantly higher in individuals who responded to IVIG compared with those who did not respond to IVIG, and correlated with a higher CK. During follow-up, a decrease in the cumulative frequency of all dominant clones correlated with a higher TIS.

CONCLUSION

In treatment-naive patients with newly diagnosed IIM, muscle tissue and peripheral blood share expanded BcR clones. In our study a higher cumulative frequency of dominant BcR clones in blood before treatment was associated with a higher CK and better treatment response, suggesting that response to IVIG may depend on the composition of the pre-treatment BcR repertoire.

Inflammatory myopathy in adults, health-related quality of life, and wellbeing: a round trip between immune disease and wellness

INTRODUCTION

Health-related quality of life (HRQoL) and wellbeing are poorer in patients with chronic conditions than in the general population, and this is the case of individuals with myositis. Research has shown a negative relationship between this disease and wellbeing, but there is little data on the effect that enhanced wellbeing has on the disease course.

AREAS COVERED

HRQoL, wellbeing, and other related concepts are examined here with special emphasis on the benefits of positive status in the physical, environmental, psychological, and social function areas for reducing the severity of the clinical course and organ damage in a chronic condition such as myositis. The factors affecting HRQoL, and wellbeing are analyzed to delineate specific strategies that will lead to improvements in the life of adult patients with myositis. The mechanisms implicated in these changes are also discussed.

EXPERT OPINION

Myositis refers to a heterogeneous group of chronic systemic autoimmune diseases. HRQoL and wellbeing are poor in these patients, and evidence suggests that improvements in this line can have positive repercussions on the course and outcome of the disease. Strategies to improve HRQoL and wellbeing should be designed for adults with myositis.

Pain in autoimmune inflammatory myopathies: a scoping review

BACKGROUND

Pain is considered a priority for research by adult patients with autoimmune inflammatory myopathy (AIM) and their families. Our aim was to review the literature for studies reporting on pain in adult AIM and to summarise their findings.

METHODS

A scoping review was conducted searching for studies in PubMed and MEDLINE including more than five adult patients with AIM and assessing pain using a patient-reported outcome measure. Study population characteristics, pain measurement and clinical correlates of pain were extracted using a standardised protocol.

RESULTS

The search strategy identified 2831 studies with 33 meeting inclusion criteria. Most studies used visual analogue scales (n=14) and/or the Medical Outcomes Study 36-Item Short Form Bodily Pain Scale (n=17). Frequency of pain and/or myalgias ranged from 64% to 100%. Subjects with AIM had significantly more pain than the general population and comparable pain to other chronic rheumatic diseases. Insufficient results were available to identify significant clinical correlates of pain in AIM.

CONCLUSION

This review suggests that the burden of pain in AIM is considerable. Still, due to the heterogeneity and low quality of the evidence, significant knowledge gaps persist. Studies are needed to characterise pain trajectories of patients with AIM.

Impaired physical function in patients with idiopathic inflammatory myopathies: results from the multicentre COVAD patient-reported e-survey

OBJECTIVES

The assessment of physical function is fundamental in the management of patients with idiopathic inflammatory myopathies (IIMs). We aimed to investigate the physical function of patients with IIMs compared with those with non-IIM autoimmune rheumatic diseases (AIRDs) utilizing Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function (PF) data obtained in the COVAD study, an international self-reported e-survey assessing the safety of COVID-19 vaccines in AIRDs.

METHODS

Demographics, AIRD diagnosis, disease activity, and PROMIS PF short form-10a data were extracted from the COVAD database. PROMIS PF-10a scores were compared between disease categories and stratified by disease activity. Factors affecting PROMIS PF-10a scores other than disease activity were identified by multivariable regression analysis in patients with inactive disease.

RESULTS

A total of 1057 IIM patients, 3635 non-IIM AIRD patients and 3981 healthy controls (HCs) responded to the COVAD e-survey from April to August 2021. Using a binomial regression model, the predicted mean of PROMIS PF-10a scores was significantly lower in IIM patients compared with non-IIM AIRD patients or HCs [36.3 (95% CI 35.5, 37.1) vs 41.3 (95% CI 40.2, 42.5) vs 46.2 (95% CI 45.8, 46.6), P < 0.001], irrespective of disease activity. The independent factors for lower PROMIS PF-10a scores in patients with inactive disease were older age, female, longer disease duration, and a diagnosis of inclusion body myositis or polymyositis.

CONCLUSION

Physical function is significantly impaired in IIMs compared with non-IIM AIRDs or HCs, even in patients with inactive disease. Our study highlights a critical need for better strategies to minimize functional disability in patients with IIMs.

Is it really myositis? Mimics and pitfalls

Idiopathic inflammatory myopathies are a heterogeneous set of systemic inflammatory disorders primarily affecting muscle. Signs and symptoms vary greatly between and within subtypes, requiring supportive laboratory and pathologic evidence to confirm the diagnosis. Several studies are typical assessments for patients with suspected inflammatory myopathy, including muscle enzymes, autoimmune markers, imaging, and muscle biopsy. Misdiagnoses of myositis are not only related to the overlap of clinical phenotype with non-inflammatory myopathies, but also due to the limitations of diagnostic tests employed. Since many of the investigative tests are non-specific, they share features with other disorders, including muscular dystrophies, endocrine, toxic, and metabolic myopathies, and other neuromuscular or rheumatologic conditions. Recognizing the limitations of tests and understanding the shared features between inflammatory and non-inflammatory myopathies can help prevent misdiagnosing myositis with one of its several mimics.

The health-related quality of life, mental health and mental illnesses of patients with inclusion body myositis (IBM): results of a mixed methods systematic review

Background

Inclusion body myositis (IBM) is a rare neuromuscular disease (NMD) and effective therapies are not available. Thus, it is relevant to determine the health-related quality of life (HRQoL) in IBM patients including aspects of mental health and illnesses.

Objectives

To identify and summarize the assessment of HRQoL, mental health and illnesses in IBM, the major factors that determine and influence them as well as the respective influence of IBM in general and compared to other NMD as a systematic review.

Methods

We performed a mixed methods systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was conducted within the databases PubMed, PsycINFO, LIVIVO and the Cochrane Database. Data were narratively summarized and categorized in the physical, psychological and social HRQoL dimensions.

Results

The systematic screening totalled 896 articles. Six studies were finally identified, comprising of 586 IBM patients. The applied patient reported outcome measures (PROMs) varied. Quantitatively, the main physical impairments (e.g. weakness, functioning, role perception) were assessed using the general population or other NMD as comparators. Results on social and psychological HRQoL were frequently inconsistent. Qualitatively, psychological and social limitations accompanied IBM related physical deteriorations.

Conclusions

A research gap exists regarding rigour determinants of HRQoL and mental illness in IBM. In-depth qualitative studies could help to prepare the ground for the assessment of long-term HRQoL data combined with appropriately focussed psychological PROMs advancing the understanding of the HRQoL in IBM throughout the course of the disease from a patient perspective.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02382-x.

[Dermatomyositis and juvenile dermatomyositis]

Dermatomyositis (DM) is an inflammatory multisystem disease of unknown etiology, which can already occur in children but first onset can also be in older adulthood. Myalgia and muscle weakness can occur later in the course of the disease or even be completely absent in some forms. Classical signs on the skin include heliotrope rash, facial erythema, Gottron's papules and nailfold capillary abnormalities. For the diagnosis, screening for the presence of myositis-specific autoantibodies has become increasingly more relevant. Muscle enzymes may be elevated but not in approximately one third of patients. In the absence of typical clinical or serologic findings, additional examination methods such as nailfold capillaroscopy, magnetic resonance imaging, electromyography, skin or muscle biopsies may help to establish the diagnosis. Depending on the clinical and serological subtype, additional screening for gastrointestinal or cardiopulmonary involvement should be considered. In adults, an age-appropriate tumor screening should also be performed. Apart from corticosteroids as induction therapy, biologics and small molecule inhibitors are gaining in importance in addition to conventional disease-modifying anti-rheumatic drugs and intravenous immunoglobulins. The prognosis for DM and juvenile DM (JDM) has improved. Most patients recover at least to some extent; however, a few patients die and a minority develop persisting muscle atrophy or severe calcinosis.

Pathophysiological Mechanisms and Treatment of Dermatomyositis and Immune Mediated Necrotizing Myopathies: A Focused Review

Idiopathic inflammatory myopathies (IIM), collectively known as myositis, are a composite group of rare autoimmune diseases affecting mostly skeletal muscle, although other organs or tissues may also be involved. The main clinical feature of myositis is subacute, progressive, symmetrical muscle weakness in the proximal arms and legs, whereas subtypes of myositis may also present with extramuscular features, such as skin involvement, arthritis or interstitial lung disease (ILD). Established subgroups of IIM include dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), anti-synthetase syndrome (ASyS), overlap myositis (OM) and inclusion body myositis (IBM). Although these subgroups have overlapping clinical features, the widespread variation in the clinical manifestations of IIM suggests different pathophysiological mechanisms. Various components of the immune system are known to be important immunopathogenic pathways in IIM, although the exact pathophysiological mechanisms causing the muscle damage remain unknown. Current treatment, which consists of glucocorticoids and other immunosuppressive or immunomodulating agents, often fails to achieve a sustained beneficial response and is associated with various adverse effects. New therapeutic targets have been identified that may improve outcomes in patients with IIM. A better understanding of the overlapping and diverging pathophysiological mechanisms of the major subgroups of myositis is needed to optimize treatment. The aim of this review is to report on recent advancements regarding DM and IMNM.

Branched chain amino acids in the treatment of polymyositis and dermatomyositis: a phase II/III, multi-center, randomized controlled trial

OBJECTIVES

To assess the efficacy and safety of branched chain amino acids (BCAAs) in the treatment of PM/DM prior to official approval of their use in Japan.

METHODS

Treatment naïve adults with PM/DM were enrolled in a randomized, double-blind trial to receive either TK-98 (drug name of BCAAs) or placebo in addition to conventional treatment. After 12 weeks, patients with an average manual muscle test (MMT) score <9.5 were enrolled in an open label extension study for a further 12 weeks. The primary end point was the change of the MMT score at 12 weeks. The secondary end points were the clinical response and the change of functional index (FI).

RESULTS

Forty-seven patients were randomized either to the TK-98 (n = 24) or placebo (n = 23) groups. The changes of MMT scores at 12 weeks were 0.70±0.19 (mean±SEM) and 0.69±0.18, respectively (P = 0.98). Thirteen patients from the TK-98 group and 12 from the placebo group were enrolled in the extension study. The MMT scores in both groups improved similarly. The increase of the FI scores of the shoulder flexion at 12 weeks was significantly greater in the TK-98 group (27.9±5.67 vs. 12.8±5.67 for the right shoulder flexion, and 27.0±5.44 vs. 13.4±5.95 for the left shoulder [P < 0.05]). Frequencies of adverse events upto 12 weeks were similar.

CONCLUSION

BCAAs showed no effect on the improvement of the muscle strength evaluated by MMT and the clinical response. However, they were partly effective for improving dynamic repetitive muscle functions.

TRIAL REGISTRATION

UMIN-CTR Clinical Trial, https://center6.umin.ac.jp/, UMIN000016233.

Consumer-based activity trackers in evaluation of physical activity in myositis patients

OBJECTIVES

Inflammatory myopathies are characterized by muscle weakness that limit activities of daily living. Daily step count is an accepted metric of physical activity. Wearable technologies such as Fitbit® enable tracking of daily step counts. We assessed psychometric properties of Fitbit® and compared the accuracy of Fitbit® step counts to ActiGraph®.

METHODS

This was a pilot, proof of concept, prospective observational study with 4 visits at 0, 1-, 3-, and 6-months in polymyositis (PM), dermatomyositis (DM), necrotizing myopathy (NM) or anti-synthetase syndrome (AS) subjects. Six core set measures [manual muscle testing, physician (MD-GDA), patient (PT-GDA), and extra-muscular disease activity, HAQ-DI and creatine kinase], 3 functional tests [six-minute walk, timed up-and-go, sit-to-stand tests] and SF-36 physical function-10 (PF10) were collected at each visit. Patients wore waist-worn Fitbit® One and ActiGraph® T3X-BT concurrently for 7 days/month for 6-months.

RESULTS

Twenty-four (10 DM, 8 PM/NM, 6 AS) patients (17 females/7 males; 91% Caucasian) were enrolled. Test-retest reliability of daily steps was strong in 1-month follow-up (ICC 0.89). Daily steps and peak 1-min cadence showed moderate-strong correlations with MD-GDA, PT-GDA, HAQ-DI, SF-36 PF10 and all three functional tests. Fitbit® and ActiGraph® step counts demonstrated good agreement and strong correlation (ICC 0.96).

CONCLUSION

Fitbit® daily steps and peak 1-min cadence are reliable and valid measures of physical activity in a cohort of myositis patients. This pilot data suggests that Fitbit® has a potential for use in clinical practice and trials to monitor physical activity in myositis patients, but larger studies are needed for further validation.

Intravenous immunoglobulins as first-line treatment in idiopathic inflammatory myopathies: a pilot study

OBJECTIVES

We explored efficacy and safety of IVIg as first-line treatment in patients with an idiopathic inflammatory myopathy.

METHODS

In this investigator-initiated phase 2 open-label study, we included 20 adults with a newly diagnosed, biopsy-proven idiopathic inflammatory myopathy, and a disease duration of less than 9 months. Patients with IBM and prior use of immunosuppressants were excluded. The standard treatment regimen consisted of IVIg (Privigen) monotherapy for 9 weeks: a loading dose (2 g/kg body weight) and two subsequent maintenance doses (1 g/kg body weight) with a 3-week interval. The primary outcome was the number of patients with at least moderate improvement on the 2016 ACR/EULAR Total Improvement Score. Secondary outcomes included time to improvement, the number of patients requiring rescue medication and serious adverse events.

RESULTS

We included patients with DM (n = 9), immune-mediated necrotizing myopathy (n = 6), non-specific myositis/overlap myositis (n = 4) and anti-synthetase syndrome (n = 1). One patient was excluded from analyses because of minimal weakness resulting in a ceiling effect. Eight patients (8/19 = 42.0%; Clopper-Pearson 95% CI: 19.6, 64.6) had at least moderate improvement by 9 weeks. Of these, six reached improvement by 3 weeks. Seven patients required rescue medication due to insufficient efficacy and prematurely ended the study. Three serious adverse events occurred, of which one was pulmonary embolism.

CONCLUSION

First-line IVIg monotherapy led to at least moderate improvement in nearly half of patients with a fast clinical response in the majority of responders.

TRIAL REGISTRATION

Netherlands Trial Register identifier, NTR6160.

Health-related quality of life and work impairment in idiopathic inflammatory myopathies in South Australia

AIM

The idiopathic inflammatory myopathies (IIM) are rare autoimmune diseases that are usually chronic and often present with skeletal muscle inflammation and weakness. We sought to examine the impact of IIM in a cohort of 50 South Australian patients on health-related quality of life (HRQOL) and work productivity (WP). We uniquely categorized patients across gender, IIM subtypes, employment status, and also whether there was extramuscular involvement from IIM.

METHODS

Multiple modalities were used, as recommended by the International Myositis Assessment and Clinical Studies Group (IMACS), to assess the impact of IIM, including manual muscle strength testing (MMT-8), the Physician and Patient Global Activity Assessments (PHGAA, PTGAA), Myositis Disease Activity Assessment Tool (MDAAT), and serum creatinine kinase (CK) levels. The impacts of IIM on HRQOL and WP were analyzed using the Medical Outcomes Study 36-items Short Form (SF-36) and Work Productivity and Activity Impairment (WPAI) questionnaires, respectively.

RESULTS

We found significantly lower HRQOL outcome scores in most of the SF-36 domains when compared to the most recent population norms (P ≤ .01). Physical health was predominantly affected with relative preservation of emotional health. There were also significant associations between MMT-8, PHGAA and PTGAA scores and HRQOL and WP.

CONCLUSIONS

Our findings highlight the significant impact of IIM on HRQOL and WP in a well-characterized cohort of patients with IIM within Australia, and therefore the importance of a holistic approach to the management of these patients.

Utility of patient-reported outcomes measurement information system (PROMIS) physical function form in inflammatory myopathy

OBJECTIVE

Idiopathic inflammatory myopathies (IIM) are a group of diseases characterized by muscle weakness, which limit activities of daily living. Patient Reported Outcomes Measurement Information System (PROMIS) is a set of outcome measures developed using NIH funding, but has not yet been studied in adult IIM. Currently, the most commonly used PROs in IIM are Health Assessment Questionnaire (HAQ-DI) and SF-36 physical function-10 (PF10), both of which have several limitations. In this study, we investigated psychometric properties of PROMIS physical function-20 (PF-20) and compared to HAQ-DI and SF-36 PF10.

METHODS

Patients with IIM completed PROMIS PF-20 and six myositis core set measures [manual muscle testing (MMT), physician (MD-GDA), patient (PT-GDA) and extra-muscular global disease activity, HAQ-DI and creatine kinase], SF-36 PF10 and functional tests [six-minute walk, timed up-and-go and sit-to-stand tests] at monthly visits over 6-months. Total improvement score (TIS) using 2016 ACR/EULAR myositis response criteria was obtained as measures of change.

RESULTS

Fifty patients [mean age, 51.6; 60% females] were enrolled; 6 PM, 24 DM, 9 NM and 11 with AS. PROMIS PF-20 showed strong test-retest reliability when repeated in 1-month. PROMIS PF-20 had moderate-strong correlations with MD-GDA, PT-GDA, MMT, HAQ-DI, SF-36 PF10, and functional tests indicating good convergent validity. Change in PROMIS PF-20 strongly correlated with TIS demonstrating good responsiveness. HAQ-DI and SF-36 PF10 exhibited similar validity and responsiveness; HAQ-DI was found to have a ceiling effect.

CONCLUSION

PROMIS PF-20 demonstrates favorable psychometric properties in a large cohort of myositis patients and offers distinct advantages.

A. R. ENS, Wada Y, Abdul Rahman Z, Ahmad S, Mohamud R, Mat Lazim N, Yean CY. Prevalence of Nasopharyngeal Carcinoma in Patients with Dermatomyositis: A Systematic Review and Meta-Analysis

Simple Summary

This first systematic review and meta-analysis on the prevalence of nasopharyngeal carcinoma in patients suffering dermatomyositis was necessitated by the absence of a true and reliable prevalence estimate necessary to adequately inform medical preparedness and decisions. Following a careful review of literature and data analyses, a prevalence of 3.3% was found. It is hoped that a clear knowledge of the actual prevalence of nasopharyngeal carcinoma in dermatomyositis patients would not only help sensitize clinicians and patients about the frequency of these disease conditions but would also enhance the adoption of precautions essential to mitigate their co-occurrence in patients.

Abstract

For more than 50 years, nasopharyngeal carcinoma (NPC) has been associated with dermatomyositis (DM), a rare idiopathic inflammatory disorder that mainly affects the skin and muscles. Although the association between these rare diseases is well-documented, the actual prevalence of NPC in DM patients remains unknown. Here, a systematic review and meta-analysis of published data was conducted in accordance with the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Electronic databases including PubMed, Scopus, ScienceDirect, and Google Scholar were searched without year or language restrictions for studies reporting the occurrence of NPC in DM patients. The study protocol was lodged with PROSPERO (CRD42021225335). A total of 95 studies covering 303 cases of NPC among 16,010 DM patients was included. Summary estimates were calculated using the random-effects model. The pooled prevalence of NPC in DM was 3.3% (95% CI, 2.5–4.3). When stratified according to study location, higher prevalence estimates were obtained for Hong Kong (36.5%), Malaysia (27.7%), and Singapore (11.9%). There was a predominance of cases among male DM patients compared with females, and most patients were aged 40 and above. Many of the NPC cases were found to be diagnosed after the diagnosis of DM. It is therefore pertinent to screen for NPC in DM patients, especially among older DM patients in the Asian region.

Mycophenolate in idiopathic inflammatory myositis: outcome data of a large South Asian cohort

BACKGROUND

Consensus on treatment of idiopathic inflammatory myositis (IIM), particularly with regard to flares and interstitial lung disease (ILD), does not exist. We studied the long-term outcome and treatment response in our large, retrospective cohort of adult South-Asian patients exclusively with IIM.

METHODOLOGY

Electronic records of IIM patients satisfying inclusion and exclusion criteria were studied longitudinally at presentation, at 3, 6, 12, 18 and 24 months and thereafter yearly till their last follow up (F/u) visit. Depending on clinical, imaging, and muscle enzyme profile during the F/u period, patients were categorised as complete (CR) and partial responders (PRs). Parameters favouring CR were assessed using multivariate logistic regression analysis. Outcome parameters and flares on immunosuppressants (IS) were then assessed in patients with/without ILD.

RESULTS

Two hundred thirty-two patients with median F/u duration of 44.5 months (25-80.25) were included. ILD was seen in 40.1%. Patients with non-Jo1 anti-synthetase antibodies (n=26) were numerically more than those with Jo-1 antibody (n=24). CR status was attained by 50.9% patients. Absence of pericardial effusion (p=0.042, OR 4.223, 95% CI: 1.05-16.9) and presence of Gottron's rash (p=0.044, OR 1.78, 95% CI 1.017-3.121) at baseline predicted CR by multivariate regression. Majority received mycophenolate during the entire F/u period. Discontinuation of steroids was feasible in 51.7% after a median duration of 24 months (18-42). After excluding patients with ILD, flares were numerically lesser in patients only on mycophenolate compared with those only on methotrexate (p=0.06). Further flares were curtailed when switched from other agents to mycophenolate.

CONCLUSION

Mycophenolate is an effective treatment option in IIM patients with and without co-existing ILD. Presence of Gottron's rash and absence of pericardial effusion were found to be predictors of favourable clinical outcome in this largest single-centre study.

Patient insights on living with idiopathic inflammatory myopathy and the limitations of disease activity measurement methods - a qualitative study

Background

The idiopathic inflammatory myopathies (IIMs) are chronic autoimmune conditions, typically resulting in proximal muscle weakness and impacting upon quality of life. Accurate measurement of IIM disease activity is imperative for appropriate medical management and carrying out valid clinical trials. The International Myositis Assessment and Clinical Studies Group (IMACS) “Disease Activity Core Set Measures” are the current gold-standard of IIM disease activity assessment. Anecdotally, patients with an IIM report that the IMACS Core Set Measures and other available methods do not necessarily capture their perceived disease activity. Investigating the patient experiences of living with an IIM and their views on the accuracy of the IMACS Core Set Measures will provide valuable insights for both clinical and research purposes.

Methods

Eighteen interviews with patients with an IIM were carried out and analysed thematically, using a grounded theory approach. Experiences on living with an IIM and perceptions on the accuracy of disease activity measurement methods were explored.

Results

Interview analysis revealed four themes: 1) fatigue, 2) pain, 3) day-to-day symptom variation, 4) limitations of creatine kinase levels and manual muscle testing.

Conclusions

This study has provided valuable insights into patient experiences of living with an IIM. Aspects of IIM disease activity perceived not to be wholly measured by the IMACS Core Set Measures have also been identified. These findings have implications for future IIM clinical care and research, in particular providing justification for research into pain, fatigue and symptom variation.

Insights into the knowledge, attitude and practices for the treatment of idiopathic inflammatory myopathy from a cross-sectional cohort survey of physicians

The idiopathic inflammatory myopathies (IIM) are heterogeneous and lead to high morbidity and mortality. Knowledge deficits among healthcare professionals could be detrimental to clinical care. Identifying areas of deficient Knowledge, Attitude and Practice (KAP) of IIM can improve physician education and patient outcomes. To assess the proportion of physicians treating IIM with poor KAP and identify the key areas of deficit. An anonymised and validated e-survey (57 questions) was circulated among physicians treating IIM (purposive sampling). Responses were evaluated using the Likert scale for good (> 70% correct response), poor (> 20% chose > 2 answers) and the rest as intermediate consensus. Descriptive statistics were used. Intergroup comparisons were done using non-parametric tests. Of 80 (9.1% of 883) respondents, 90% were rheumatologists and 37.5% academicians. The knowledge base of treating physicians was good in specific domains such as triggers (80-90%), clinical presentation (MDA5, statin myositis, steroid myopathy, anti-synthetase syndrome) (82-92%), IIM mimics (41-89%), investigations (23-92%) and risk of osteoporosis in IIM (79%). There is also an intermediate knowledge base/consensus for outcome measures (30-56%) and response criteria (30-53%). There was poor knowledge and consensus on trials (27-34%), EULAR/ACR criteria (31%) and exercise-based interventions (17-62%). While 90% agree on the need for muscle biopsy to diagnose polymyositis, only one-third advocated it for juvenile and adult DM. Physicians have a good understanding of the triggers, clinical presentation and mimics of IIM. Poor to intermediate knowledge and consensus exists regarding muscle biopsy, outcome measures, response criteria and exercise-based interventions, which could be addressed through future focussed educational initiatives.

Recurrent focal myositis developing into a generalised idiopathic inflammatory myopathy with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase autoantibodies

We present the case of a 43-year-old woman with generalised idiopathic inflammatory myopathy (IIM) with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) autoantibodies (Abs) that developed following recurrent focal myositis. Anti-HMGCR Abs are myositis-specific Abs that are associated with immune-mediated necrotising myopathy, a subtype of IIM that is characterised by relatively prominent and severe muscle involvement, generally necessitating multimodal immunosuppressant treatment. While earlier reports have described patients developing polymyositis following focal myositis, this is the first report to describe a patient developing IIM with anti-HMGCR Abs following focal myositis. Thus, clinicians should be aware of the possibility that focal myositis may develop into a generalised IIM and should instruct the patient and monitor the patient accordingly.

Revisiting Pathological Classification Criteria for Adult Idiopathic Inflammatory Myopathies: In-Depth Analysis of Muscle Biopsies and Correlation Between Pathological Diagnosis and Clinical Manifestations

The European Neuromuscular Centre (ENMC) pathological classification criteria of idiopathic inflammatory myopathies (IIMs) are debatable. The aim of this study was to explore their practicability and reproducibility. We conducted a retrospective analysis of 57 cases of IIMs excluding dermatomyositis (DM) and sporadic inclusion body myositis (sIBM) by in-depth analysis of muscle biopsies and comparisons of the clinical characteristics among polymyositis (PM), non-specific myositis (NSM) and necrotizing autoimmune myopathy (NAM). In 57 non-DM/sIBM-IIM cases, 25 were classified as PM, 15 as NSM, and 17 as NAM. Among them, 51 underwent multilevel sectioning examination of biopsies, with pathological changes at different levels warranting diagnostic rectification in 11 patients (21.57%): 4 PM were reclassified as NSM, and 7 NSM as NAM. Applying atypical CD8+ T cells surrounding non-necrotic muscle fibers resulted in diagnostic rectification from NSM to PM in 2 patients; using 20 T cells (instead of 10) as the threshold for the perivascular infiltration led to diagnostic rectification from NSM to NAM in 9 patients. There were no differences in disease duration or treatment outcomes among the subgroups. The strict pathological criteria to distinguish non-DM/sIBM-IIMs are of limited practicability and reproducibility, and may be of limited clinical significance.

Diagnostic value of additional histopathological fascia examination in idiopathic inflammatory myopathies

Background and purpose

Correct diagnosis of idiopathic inflammatory myopathies (IIM) may prevent harm from both lack of treatment in IIM patients and unnecessary treatment in non‐IIM patients. However, it is unknown whether additional histopathological fascia examination may contribute to diagnosing IIM.

Methods

Thirty‐two magnetic resonance imaging guided en bloc biopsies from patients diagnosed with IIM (except inclusion body myositis) from 2010 to 2017 were reviewed: dermatomyositis (DM) (n = 6), non‐specific/overlap myositis (NM/OM) (n = 11), immune‐mediated necrotizing myopathy (n = 12) and anti‐synthetase syndrome (n = 3). Muscle biopsy specimens were examined according to the 2004 European Neuromuscular Centre (ENMC) criteria. Fascia was subsequently examined for the presence of lymphocytic infiltrates. Isolated fascia involvement was defined as the presence of lymphocytic infiltrates in the fascia/epimysium on histopathology in the absence of any ENMC muscle histopathology/immunohistochemistry criteria.

Results

One patient with DM (17%) and one patient with NM/OM (9%) had isolated fascia involvement. One patient with immune‐mediated necrotizing myopathy (8%) and one patient with anti‐synthetase syndrome (33%) had fascia involvement, albeit in combination with muscle involvement.

Conclusion

Histopathological fascia examination may contribute to early diagnosis of DM and NM/OM in a small proportion of patients.

The clinical and histopathological features of idiopathic inflammatory myopathies with asymmetric muscle involvement

The objective is to determine the frequency of idiopathic inflammatory myopathies (IIMs) with asymmetric muscle involvement (IIMs-A) as initial manifestations in total IIMs and to compare the demographic, clinical, histopathological and radiological characteristics of IIMs-A with classical IIMs (IIMs-C). We retrospectively reviewed the clinical, laboratory, muscle images, histopathological features and treatment response of patients at the Qilu hospital who were diagnosed as IIMs from April 2005 to August 2017. We found among 134 IIMs patients, 13(9.2%) patients with IIMs-A were identified, of which 7 patients were diagnosed as dermatomyositis (DM), 2 as polymyositis (PM), 4 as immune-mediated necrotizing myopathy (IMNM) using the European Neuromuscular Centre (ENMC) criteria. The mean age of our group was 59.1 years old. The duration from the initial symptoms to the first examination was less than 12 months in 12 patients (92.3%). 46.2% patients accompanied with weakness of distal limbs and bulbar symptoms. Finger flexion involvement was found in 5 patients (38.5%). There was no patient that finger flexion was weaker than shoulder abduction. The creatine kinase (CK) level in the serum ranged from 41 IU/L to 9125 IU/L (average: 3192.7 ± 2769.9 IU/L). Serum positive anti-mitochondrial antibodies (AMAs) were found in four patients (30.8%). Endomysial fibrosis and inflammatory cell infiltration were detected in 92.3%, 84.6% patients respectively. Mitochondrial abnormalities in histopathological finding of muscle biopsy were seen in 100% cases. The major histocompatibility complex class I (MHC-I) (84.6%) and class II (MHC-II) (92.3%) expressed on muscle biopsies from almost all cases of our patients. MAC antibody, however, was detected in only 20-40% patients. Eight patients (61.5%) had favorable outcomes. The conclusion was that IIMs-A presented mainly in DM, generally with mitochondrial abnormality and highly positive AMAs. The relationship between the presence of AMAs and the asymmetric muscle involvement in DM needs to be further clarified. We should also consider the diagnosis of IIMs when the patient has features of positive AMAs and asymmetric muscle involvement.

Autoantibody testing in idiopathic inflammatory myopathies

The diagnosis and classification of idiopathic inflammatory myopathies are based mainly on clinical and histological features. The discovery of myositis-specific and myositis-associated antibodies has simplified the (sub)classification of inflammatory myopathies. Patients suspected of having an idiopathic inflammatory myopathy should undergo routine antibody testing to gain more insight into distinct phenotypes, comorbidities, treatment response and prognosis. Furthermore, autoantibody testing can help in patients with atypical patterns of weakness or with an unresolved limb-girdle myopathic phenotype, or interstitial lung disease. However, some important technical and methodological issues can hamper the interpretation of antibody testing; for example, some antibodies are not included in the widely available line blots. We aim to provide a practical review of the use of autoantibody testing in idiopathic inflammatory myopathies in clinical practice.

Autoimmune Myopathies: Updates on Evaluation and Treatment

The major forms of autoimmune myopathies include dermatomyositis (DM), polymyositis (PM), myositis associated with antisynthetase syndrome (ASS), immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). While each of these conditions has unique clinical and histopathological features, they all share an immune-mediated component. These conditions can occur in isolation or can be associated with systemic malignancies or connective tissue disorders (overlap syndromes). As more has been learned about these conditions, it has become clear that traditional classification schemes do not adequately group patients according to shared clinical features and prognosis. Newer classifications are now utilizing myositis-specific autoantibodies which correlate with clinical and histopathological phenotypes and risk of malignancy, and help in offering prognostic information with regard to treatment response. Based on observational data and expert opinion, corticosteroids are considered first-line therapy for DM, PM, ASS, and IMNM, although intravenous immunoglobulin (IVIG) is increasingly being used as initial therapy in IMNM related to statin use. Second-line agents are often required, but further prospective investigation is required regarding the optimal choice and timing of these agents.

Current Classification and Management of Inflammatory Myopathies

Inflammatory disorders of the skeletal muscle include polymyositis (PM), dermatomyositis (DM), (immune mediated) necrotizing myopathy (NM), overlap syndrome with myositis (overlap myositis, OM) including anti-synthetase syndrome (ASS), and inclusion body myositis (IBM). Whereas DM occurs in children and adults, all other forms of myositis mostly develop in middle aged individuals. Apart from a slowly progressive, chronic disease course in IBM, patients with myositis typically present with a subacute onset of weakness of arms and legs, often associated with pain and clearly elevated creatine kinase in the serum. PM, DM and most patients with NM and OM usually respond to immunosuppressive therapy, whereas IBM is largely refractory to treatment. The diagnosis of myositis requires careful and combinatorial assessment of (1) clinical symptoms including pattern of weakness and paraclinical tests such as MRI of the muscle and electromyography (EMG), (2) broad analysis of auto-antibodies associated with myositis, and (3) detailed histopathological work-up of a skeletal muscle biopsy. This review provides a comprehensive overview of the current classification, diagnostic pathway, treatment regimen and pathomechanistic understanding of myositis.

Quality of life correlates with muscle strength in patients with dermato- or polymyositis

The aim of this study was to compare health-related quality of life (HQoL) in adults with dermatomyositis (DM) or polymyositis (PM) with a healthy control group and to assess whether muscle strength was associated with HQoL in patients with DM or PM. A cross-sectional study was performed and included 75 patients with DM or PM and 48 healthy controls. HQoL was assessed by the Short Form 36 questionnaire (SF-36). Muscle strength of the patients was assessed using the Manual Muscle Test-8 (MMT8). Covariables and possible confounding factors were collected by validated tools. Associations were determined in multiple linear regression models. The patients had significantly lower HQoL than the control group in both the physical component summary score (PCS) and the mental component summary score (MCS). Thus, the PCS-difference between groups was 32% (p < 0.001), whereas the MCS-difference was 14% (p < 0.001). Muscle strength was associated with one domain in the patients; Physical Function (β = 1.2; 95% confidence interval 0.37 to 2.1). No statistically significant associations were found between muscle strength and HQoL in the remaining domains. Patients with DM or PM have reduced HQoL compared to healthy controls. Notably, muscle strength was associated with scores of the domain reflecting perceived physical function in patients. These findings corroborate the validity of including selected patient reported outcomes in the evaluation and monitoring of patients with DM or PM.

Health-Related Quality of Life (HRQoL) in Idiopathic Inflammatory Myopathy: A Systematic Review

Health-related quality of life (HRQoL) is a research priority in chronic diseases. We undertook a systematic review (registration #CRD42015024939) to identify, appraise and synthesize the evidence relating to HRQoL in idiopathic inflammatory myopathies (IIM). A comprehensive search was conducted in August 2015 using CINAHL, EMBase and Pubmed to identify studies reporting original data on HRQoL in IIM using generic HRQoL instruments. Characteristics of samples and results from selected studies were extracted and appraised using a standardized approach. Qualitative synthesis of the results was performed. Ten studies including a total of 654 IIM subjects were included in this systematic review. HRQoL was significantly impaired in all subsets of IIM compared with the general population. Disease activity, disease damage and chronic disease course were associated with poorer HRQoL. Insufficient or conflicting results were found in associations between clinical features, treatment, disease duration and mood or illness perception, and HRQoL in IIM. This study suggests that HRQoL is impaired in IIM. However, due to the paucity and heterogeneity of the evidence to date, robust estimates are lacking and significant knowledge gaps persist. There is a need for studies that systematically investigate the correlates and trajectory of HRQoL in IIM.

Neuromuscular complications in cancer

Cancer is becoming a treatable and even often curable disease. The neuromuscular system can be affected by direct tumor invasion or metastasis, neuroendocrine, metabolic, dysimmune/inflammatory, infections and toxic as well as paraneoplastic conditions. Due to the nature of cancer treatment, which frequently is based on a DNA damaging mechanism, treatment related toxic side effects are frequent and the correct identification of the causative mechanism is necessary to initiate the proper treatment. The peripheral nervous system is conventionally divided into nerve roots, the proximal nerves and plexus, the peripheral nerves (mono- and polyneuropathies), the site of neuromuscular transmission and muscle. This review is based on the anatomic distribution of the peripheral nervous system, divided into cranial nerves (CN), motor neuron (MND), nerve roots, plexus, peripheral nerve, the neuromuscular junction and muscle. The various etiologies of neuromuscular complications - neoplastic, surgical and mechanic, toxic, metabolic, endocrine, and paraneoplastic/immune - are discussed separately for each part of the peripheral nervous system.

Immunotherapies for Immune-Mediated Myopathies: A Current Perspective

Until recently, the treatment of immune-mediated inflammatory myopathies has largely been empirical with glucocorticoids, steroid-sparing immunosuppressive drugs, and intravenous immunoglobulin. However, a proportion of patients are only partially responsive to these therapies, and there has been a need to consider alternative treatment approaches. In particular, patients with inclusion body myositis are resistant to conventional immunotherapies or show only a transient response, and remain a major challenge. With increasing recognition of the different subtypes of immune-mediated inflammatory myopathies, and improved understanding of their pathogenesis, more targeted treatments are now being trialled. The overall approach to treatment, and novel therapies targeting B cells, T cells, and specific cytokines are discussed in this review.

Neuromuscular issues in systemic disease

The neuromuscular system can be involved in several systemic conditions. Clinical manifestations can appear at onset or throughout the course of the disease process. New investigational methods, including imaging of peripheral nerves, new laboratory tests, and antibodies, are available. In addition to symptomatic therapies, specific treatment options, such as for familial amyloid neuropathy and Fabry's disease, are becoming increasingly available. Pathomechanisms vary depending on the underlying disease process. In addition to metabolic, hormonal, immune, and antibody-mediated mechanisms, in some generalized diseases, genetic causes need to be considered. This review focuses on different aspects of the peripheral nervous system including the nerve roots, plexuses, mononeuropathies and generalized neuropathies, neuromuscular junction disorders, muscle, and autonomic nervous system.