Idiopathic Inflammatory Myopathies Cohort Research Articles

Anti-synthetase syndrome is associated with a higher risk of hospitalization among patients with idiopathic inflammatory myopathy and COVID-19.

Data with fine granularity about COVID-19-related outcomes and risk factors were still limited in the idiopathic inflammatory myopathies (IIMs) population. This study aimed to investigate clinical factors associated with hospitalized and severe COVID-19 in patients with IIMs, particularly those gauged by myositis-specific antibodies. This retrospective cohort study was conducted in the Renji IIM cohort in Shanghai, China, under an upsurge of SARS-CoV-2 omicron variant infections from December 2022 to January 2023. Clinical data were collected and analyzed by multivariable logistic regression to determine risk factors. High-dimensional flow cytometry analysis was performed to outline the immunological features. Among 463 infected patients in the eligible cohort (n=613), 65 (14.0%) were hospitalized, 19 (4.1%) suffered severe COVID-19, and 10 (2.2%) died. Older age (OR=1.59/decade, 95% CI 1.18 to 2.16, p=0.003), requiring family oxygen supplement (2.62, 1.11 to 6.19, 0.028), patients with anti-synthetase syndrome (ASyS) (2.88, 1.12 to 7.34, 0.027, vs. other dermatomyositis), higher IIM disease activity, and prednisone intake >10mg/day (5.59, 2.70 to 11.57, <0.001) were associated with a higher risk of hospitalization. Conversely, 3-dose inactivated vaccination reduced the risk of hospitalization (0.10, 0.02 to 0.40, 0.001, vs. incomplete vaccination). Janus kinase inhibitor (JAKi) pre-exposure significantly reduced the risk of severe COVID-19 in hospitalized patients (0.16, 0.04 to 0.74, 0.019, vs. csDMARDs). ASyS patients with severe COVID-19 had significantly reduced peripheral CD4+ T cells, lower CD4/CD8 ratio, and fewer naive B cells but more class-switched memory B cells compared with controls. ASyS and family oxygen supplement were first identified as risk factors for COVID-19-related hospitalization in patients with IIMs. JAKi pre-exposure might protect IIM patients against severe COVID-19 complications.

Global disparities in the treatment of idiopathic inflammatory myopathies: results from an international online survey study.

We aimed to explore current practice and interregional differences in the treatment of idiopathic inflammatory myopathies (IIMs). We triangulated these observations considering countries' gross national income (GNI), disease subtypes, and symptoms using patient-reported information. A cross-sectional ancillary analysis of the 'COVID-19 vaccination in auto-immune disease' (COVAD) e-survey containing demographic characteristics, IIM subtypes (DM, PM, IBM, anti-synthetase syndrome [ASSD], immune-mediated necrotizing myopathy [IMNM], overlap myopathies [OM]), current symptoms (surrogate for organ involvement) and treatments (corticosteroids [CS], immunomodulators [IM], i.e. antimalarials, immunosuppressants [IS], IVIG, biologic treatments and targeted-synthetic small molecules). Treatments were presented descriptively according to continents, GNI, IIM and organ involvement, and associated factors were analysed using multivariable binary logistic regressions. Of 18 851 respondents from 94 countries, 1418 with IIM were analysed (age 61 years, 62.5% females). DM (32.4%), IBM (24.5%) and OM (15.8%) were the most common subtypes. Treatment categories included IS (49.4%), CS (38.5%), IM (13.8%) and IVIG (9.4%). Notably, treatments varied across regions, GNI categories (IS mostly used in higher-middle income, IM in lower-middle income, IVIG and biologics largely limited to high-income countries), IIM subtypes (IS and CS associated with ASSD, IM with OM and DM, IVIG with IMNM, and biologic treatments with OM and ASSD) and disease manifestations (IS and CS with dyspnoea). Most inter-regional treatment disparities persisted after multivariable analysis. We identified marked regional treatment disparities in a global cohort of IIM. These observations highlight the need for international consensus-driven management guidelines considering patient-centred care and available resources.

Identification of Novel Associations and Localization of Signals in Idiopathic Inflammatory Myopathies Using Genome-Wide Imputation.

The idiopathic inflammatory myopathies (IIMs) are heterogeneous diseases thought to be initiated by immune activation in genetically predisposed individuals. We imputed variants from the ImmunoChip array using a large reference panel to fine-map associations and identify novel associations in IIM. We analyzed 2,565 Caucasian IIM patient samples collected through the Myositis Genetics Consortium (MYOGEN) and 10,260 ethnically matched control samples. We imputed 1,648,116 variants from the ImmunoChip array using the Haplotype Reference Consortium panel and conducted association analysis on IIM and clinical and serologic subgroups. The HLA locus was consistently the most significantly associated region. Four non-HLA regions reached genome-wide significance, SDK2 and LINC00924 (both novel) and STAT4 in the whole IIM cohort, with evidence of independent variants in STAT4, and NAB1 in the polymyositis (PM) subgroup. We also found suggestive evidence of association with loci previously associated with other autoimmune rheumatic diseases (TEC and LTBR). We identified more significant associations than those previously reported in IIM for STAT4 and DGKQ in the total cohort, for NAB1 and FAM167A-BLK loci in PM, and for CCR5 in inclusion body myositis. We found enrichment of variants among DNase I hypersensitivity sites and histone marks associated with active transcription within blood cells. We found novel and strong associations in IIM and PM and localized signals to single genes and immune cell types.

Autoantigenic properties of the aminoacyl tRNA synthetase family in idiopathic inflammatory myopathies

ObjectivesAutoantibodies are thought to play a key role in the pathogenesis of idiopathic inflammatory myopathies (IIM). However, up to 40% of IIM patients, even those with clinical manifestations of anti-synthetase syndrome (ASSD), test seronegative to known myositis-specific autoantibodies. We hypothesized the existence of new potential autoantigens among human cytoplasmic aminoacyl tRNA synthetases (aaRS) in patients with IIM. MethodsPlasma samples from 217 patients with IIM according to 2017 EULAR/ACR criteria, including 50 patients with ASSD, 165 without, and two with unknown ASSD status were identified retrospectively, as well as age and gender-matched sera from 156 population controls, and 219 disease controls. Patients with previously documented ASSD had to test positive for at least one of the five most common anti-aaRS autoantibodies (anti-Jo1, -PL7, -PL12, -EJ, and -OJ) and present with one or more of the following clinical manifestations: interstitial lung disease, myositis, arthritis, Raynaud's phenomenon, fever, or mechanic's hands. Demographics, laboratory, and clinical data of the IIM cohort (ASSD and non-ASSD) were compared. Samples were screened using a multiplex bead array assay for presence of autoantibodies against a panel of 117 recombinant protein variants, representing 33 myositis-related proteins, including all nineteen cytoplasmic aaRS. Prospectively collected clinical data for the IIM cohort were retrieved and compared between groups within the IIM cohort and correlated with the results of the autoantibody screening. Principal component analysis was used to analyze clinical manifestations between ASSD, non-ASSD groups, and individuals with novel anti-aaRS autoantibodies. ResultsWe identified reactivity towards 16 aaRS in 72 of the 217 IIM patients. Twelve patients displayed reactivity against nine novel aaRS. The novel autoantibody specificities were detected in four previously seronegative patients for myositis-specific autoantibodies and eight with previously detected myositis-specific autoantibodies. IIM individuals with novel anti-aaRS autoantibodies (n = 12) all had signs of myositis, and they had either muscle weakness and/or muscle enzyme elevation, 2/12 had mechanic's hands, 3/12 had interstitial lung disease, and 2/12 had arthritis. The individuals with novel anti-aaRS and a pathological muscle biopsy all presented widespread up-regulation of major histocompatibility complex class I. The reactivities against novel aaRS could be confirmed in ELISA and western blot. Using the multiplex bead array assay, we could confirm previously known reactivities to four of the most common aaRS (Jo1, PL12, PL7, and EJ (n = 45)) and identified patients positive for anti-Zo, -KS, and -HA (n = 10) that were not previously tested. A low frequency of anti-aaRS autoantibodies was also detected in controls. ConclusionOur results suggest that most, if not all, cytoplasmic aaRS may become autoantigenic. Autoantibodies against new aaRS may be found in plasma of patients previously classified as seronegative with potential high clinical relevance.

Using multi-parametric quantitative MRI to screen for cardiac involvement in patients with idiopathic inflammatory myopathy

Idiopathic inflammatory myopathies (IIM) is a group of heterogeneous autoimmune systemic diseases, which not only involve skeletal muscle but also myocardium. Cardiac involvement in IIM, which eventually develops into heart failure, is difficult to identify by conventional examinations at early stage. The aim of this study was to investigate if multi-parametric cardiac magnetic resonance (CMR) imaging can screen for early cardiac involvement in IIM, compared with clinical score (Myositis Disease Activity Assessment Tool, MDAAT). Forty-nine patients of IIM, and 25 healthy control subjects with comparable age-range and sex-ratio were enrolled in this study. All subjects underwent CMR examination, and multi-slice short-axis and 4-chamber cine MRI were acquired to evaluate biventricular global circumferential strain (GCS) and global longitudinal strain (GLS). Native T1 and T2 mapping were performed, and post-contrast T1 mapping and LGE were acquired after administration of contrast. A CMR score was developed from native T1 mean and T2 mean for the identification of cardiac involvement in the IIM cohort. Using contingency tables MDAAT and CMR were compared and statistically analyzed using McNemar test. McNemar’s test revealed no significant difference between CMR score and MDAAT (p = 0.454). CMR score had potential to screen for early cardiac involvement in IIM patients, compared to MDAAT.

P114 A service evaluation of the Myositis clinic at London North West University Healthcare Trust

Abstract Background/Aims The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare diseases, primarily characterised by inflammation of skeletal muscle which leads to muscle weakness, but often involving several other organ systems. The myositis service at London North West University Healthcare Trust (LNWUH) was created in 2017 with the aim of standardising care and improving clinical outcomes for patients. The International Myositis Assessment and Clinical Studies Group (IMACS) established disease activity core set measures to validate clinical response to treatment in studies, but the optimal treatment and real world data on clinical outcomes for patients with IIM is not well described. We undertook a service evaluation to understand the cohort, assess the effectiveness of the service, and in order to inform future service improvements for patients with IIM. Methods We performed a retrospective analysis of the IIM cohort at LNWUH as of January 2021, which consisted of 40 patients. Data were gathered from electronically stored notes and results. Results 65% of our cohort were female, 35% were male. The age range was 18-85. The most common subgroup was dermatomyositis (22.5%). The presenting symptoms included muscle weakness (82.5%), dysphagia (32.5%) and interstitial lung disease (ILD) (27.5%). The most common primary antibody was HMG-CoA reductase, followed by anti-Jo1. More than one antibody was present in 47.5% of patients. three patients had no detectable antibody. 1 in 5 patients had a normal creatine kinase (CK) at baseline. 89% had a raised troponin at baseline, with only two of these having confirmed cardiac involvement on imaging (echocardiogram or cardiac MRI). 30% of the cohort are currently taking mycophenolate mofetil (MMF), 27.5% are taking methotrexate, and 20% are taking hydroxychloroquine. 30% of patients have received rituximab, 20% intravenous immunoglobulin (IVIg), and 7.5% cyclophosphamide. Normalisation of CK was seen in 80% of patients, compared with 20% for pulmonary function tests (PFTs). 63% of patients were in clinical remission one year after diagnosis. Three patients died, two from MDA5-positive rapidly progressive interstitial lung disease. Conclusion In our cohort of patients with IIM, most patients had a significant improvement in their CK and muscle strength with treatment, but there remain challenges. We have established a baseline demographic and clinical outcome data for our cohort that will be used to make service improvements in line with the BSR guideline in development “Adult patients with idiopathic inflammatory myopathy”, and to assess future performance of the service. Disclosure I. Welding: None. A. Isaacs: None.

Distribution and trajectory of direct and indirect costs of idiopathic inflammatory myopathies

ObjectivesTo estimate the annual direct and indirect costs associated with Idiopathic Inflammatory Myopathies (IIM) over time, including the pre-diagnostic period. MethodsA cohort of incident adult IIM patients (n = 673) was identified from the Swedish National Patient Register from 2010 to 2016 and matched with general population comparators (n = 3343). Follow-up started at IIM diagnosis and corresponding date in the general population. International Classification of Diseases codes (ICD-10) were used for IIM case definition. Costs were calculated using national register data. ResultsThe costs related to IIM started to increase 2 years before diagnosis. In the year following diagnosis, the mean annual IIM cost was €21 639 compared to €4816 in the general population. Five years after diagnosis, the mean annual cost in the IIM cohort was €12 796. Outpatient visits, hospitalizations and productivity loss were the components driving the increment in overall annual disease-related expenditures. Indirect costs accounted for a significant portion of IIM long-term societal costs. The highest costs were found in individuals of working age with cancer-associated IIM. ConclusionsThe mean annual costs in IIM were 3 to 5 times higher than in the general population in the 5-year period following diagnosis. These costs started to increase long before diagnosis, were at their peak in the year post-diagnosis and remained elevated thereafter. Indirect costs contributed to a substantial portion of this increment. Early in the IIM disease course, clinicians and allied health professionals should aim to improve function, reduce damage and address barriers to return-to-work to mitigate these costs.

P156 Myositis flares are associated with reduced work productivity and fewer hours worked: illustration of the future potential of digital healthcare solutions in rheumatic diseases

Background/Aims The digital healthcare revolution provides the opportunity for clinicians and researchers to collect useful data on a frequent and remote basis. Work ability is impacted by many rheumatic diseases, including the idiopathic inflammatory myopathies (IIMs), however, methods to assess the real-time impacts are limited. This study aims to explore the impact of IIM flares and symptoms upon employment using frequently collected data via a smartphone-based app. Methods The Myositis Physical Activity Device Study recruited a UK-based adult IIM cohort who completed weekly employment and flare questions via a specially designed smartphone-based app throughout a 91 day period in 2019/20. Employment-related questions were assessed every week (see Table 1 for details). Flares were reported via a weekly question. Employment variables were compared between flare and non-flare weeks using descriptive statistics. The relationship between flares and work productivity was assessed using multi-level mixed effects logistic regression modelling, adjusted for age and sex. Results Data on 13 (69% female) employed participants was analysed. A median of 5 flares were reported per patient during the three month period (IQR 3, 9). Summary employment results are displayed in Table 1. Participants reported greater impact of IIM upon employment, lower productivity and fewer hours worked during a flare week, compared to a non-flare week. There was a significant association between flares and detrimental impact upon work productivity (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03, 1.12, p < 0.01). Flares were also significantly associated with an increased number of work hours missed due to IIM (OR 1.04, 95% CI 1.01, 1.08, p = 0.02) P156 Table 1:- Summary employment parameters compared between flare and non-flare weeksEmployment parameterAnswer formatWhole study period (159 weeks)Flare weeks (60 weeks)Non-flare weeks (99 weeks)p-value*Number of weeks’ work productivity affected by IIM (%)Dichotomous - “yes”, “no”54 (34.0)33 (55.0)21 (21.2)<0.01Mean effect of IIM upon work productivity (SD)Visual analogue scale - “Myositis had no effect on work" (0);“Myositis completely prevented me from working” (100)29.8 (28.8)46.2 (33.3)19.9 (20.0)<0.01Mean number of scheduled work hours per week per participant (SD)Numerical33.2 (15.8)36.9 (19.33)31.0 (13.0)<0.01Mean number of hours worked per week per participant (SD)Numerical23.5 (15.1)18.86 (17.1)26.23 (13.2)<0.01Proportion of hours worked per week per participant / % (SD)Calculated by research team73.7 (38.7)55.9 (43.2)84.7 (31.1)<0.01Mean number of hours of weekly work missed due to IIM per participant (SD)Numerical6.6 (16.6)14.9 (23.4)1.5 (6.6)<0.01Proportion of hours of weekly work missed due to IIM per participant / % (SD)Calculated by research team12.7% (29.5)29.2 (41.1)2.6 (10.0)<0.01SD = standard deviation *Categorical variables were compared using the Chi-squared test and continuous variables compared using the student t-test. Conclusion Our study has demonstrated that IIM flares are significantly associated with detrimental impact upon employment ability. On average, patients lost 15 hours of work a week during a flare compared to less than 2 hours outside a flare. The economic and personal impact of flares highlights the need for research in this area, with the aim of allowing early identification and instigation of treatment and possible need for supported work. Smartphone based remote monitoring of flares and other pertinent variables could enhance digital consultations, which may become more common in the post COVID-19 setting. Disclosure J.C. Williams: None. A.G.S. Oldroyd: None. W.G. Dixon: None. H. Chinoy: None.

High early mortality in idiopathic inflammatory myopathies: results from the inception cohort at a tertiary care centre in northern India.

We determined the mortality along with the proportion of disease related adverse events measured individually and by a composite adverse outcome (devised by including deaths, disability, relapses and minimal response) and its predictors in an inception cohort of idiopathic inflammatory myopathies (IIM). IIM from the MyoCite cohort (December 2017-19) were reviewed for early outcomes (mortality, IMACS core set). Comparisons were drawn between those meeting the primary and secondary outcomes. Of 70 patients [62 adults, M:F = 1:4.8, age 43 (28.5-51) and eight children, M:F = 1:1, 14.5 (8.8-16)], dermatomyositis (DM) was the most common subset [29 (41.4%) adults; 7 (87.5%) children]. Over 10 (4-15) months, 10 (15.2%) died and four polymyositis were reclassified. One-year survival for anti-melanoma differentiation antigen 5 (MDA5) subtype was 30% and anti-synthetase syndrome (ARS) subtype was 75%. Overall, lower respiratory infections were the most common cause of death [n = 3 (30%)] followed closely by malignancy and rapidly progressive interstitial lung disease (RP-ILD). Amongst survivors, a major IMACS response was recorded in 54.5% adults and 100% children. Thirty per cent suffered from moderate to severe disability and 16.7% experienced relapses. Overall, two-thirds accrued the composite adverse outcome. On multivariate analysis, older age and anti-MDA5 predicted mortality. Arthritis, rash and positive ANA reduced and anti-MDA5 increased the risk for the composite adverse outcome. Indian patients with IIM suffer high early mortality attributable to infection, cancer and RP-ILD, calling for high vigilance post diagnosis. Autoantibodies and certain clinical features identify risk for composite adverse outcomes.

Teleconsultation experience with the idiopathic inflammatory myopathies: a prospective observational cohort study during the COVID-19 pandemic.

Teleconsultation has assumed a central role in the management of chronic and disabling rheumatic diseases, such as the idiopathic inflammatory myopathies (IIM), during COVID-19. However, the feasibility, challenges encountered, and outcomes remain largely unexplored. Here, we describe our teleconsultation experience in a prospectively followed cohort of adult and juvenile IIM. 250 IIM enrolled into the MyoCite cohort (2017-ongoing) were offered the option of audio/visual teleconsultation using WhatsApp during the nationwide lockdown. Clinical outcomes (major/minor relapse) and prescription changes were compared between IIM subsets. Socio-demographic and clinico-serological characteristics of those who sought teleconsultation were compared with those who did not. 151 teleconsultations were sought over a 93 day period by 71 (52.2%) of 136 IIM (median age 38 years, F:M 4.5:1). Nearly one-third (38%) consulted on an emergency basis, with voice consultations being the primary medium of communication. Over a quarter (26.8%) reported relapse (15.5% minor, 11.3% major), these being more common in JDM [71.4%, OR 8.9 (1.5–51)] as compared with adult IIM, but similar across various antibody-based IIM subtypes. Patients who relapsed required more consultations [2(2–3) vs 1(1–2), p 0.009]. The demographic and socioeconomic profile of the patients seeking consultation (n = 71) was not different from those who did not (n = 65). Voice-based teleconsultations may be useful to diagnose and manage relapses in IIM during the pandemic. Patient education for meticulous and timely reporting may be improve care, and larger multicentre studies may identify subsets of IIM that require greater care and early tele-triage for effective management of the condition.

The Low Prevalence of Inclusion Body Myositis in an Outpatient Rheumatology Myositis Cohort.

IntroductionSporadic inclusion body myositis (IBM) is a rare type of myopathy of unknown etiology typified by the presence of distinctive muscle fiber inclusions. IBM belongs to a larger family of conditions called the idiopathic inflammatory myopathies (IIM). This study seeks to compare the prevalence, clinical manifestations, and disease course of IBM patients to a cohort of polymyositis (PM) and dermatomyositis (DM) patients in an outpatient rheumatology myositis cohort.MethodsWe conducted a retrospective chart review of all adult patients attending rheumatology clinics at the Cook County Hospital from 2006 to 2011 with the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) diagnoses of idiopathic inflammatory myopathies (IIM). Data collected included patient demographics, serial muscle strength testing, serial creatine kinase (CK), muscle biopsies, and immunosuppressive therapies received. ResultsWe identified 112 patients with IIM with the following breakdown: 66 - dermatomyositis, 42 - polymyositis, and four - IBM. These four patients represent the primary cohort. They had a mean age of 67 years (range 62-74), the mean follow-up period of 15 months (range 3-47), mean initial muscle strength in the weakest group of 3.75 (range 2-5, standard deviation [SD]=1.3), mean initial CK of 1,968 U/L (range 313-4,795, SD=1,970), mean final muscle strength in the weakest group of 3.75 (range 3-4, SD=0.5), mean final CK of 1,326 U/L (range 213-2,943, SD=1,200).ConclusionsOur IBM patients had many features similar to other described IBM cohorts, including older age, male predominance, slow progression (stable CK and muscle strength), and lack of response to immunosuppressive therapy. Interestingly, we found a low prevalence of IBM in our outpatient rheumatology IIM cohort.

Statin use in patients with non-HMGCR idiopathic inflammatory myopathies: A retrospective study.

BackgroundStatins are the most widely used lipid lowering therapies which reduce cardiovascular risk, but are associated with muscular adverse events (AEs). Idiopathic inflammatory myopathies (IIM) are autoimmune diseases of the muscle with higher risk of cardiovascular disease. More data is needed regarding statin safety in patients with intrinsic muscle disease such as IIM.HypothesisStatins are tolerated in patients with IIM without leading to significant increase in muscular AEs.MethodsStatin use was retrospectively examined in a longitudinal IIM cohort. Safety analysis included assessment of muscular and nonmuscular AEs by chart review. IIM patients receiving a statin during the cohort follow‐up period were matched to IIM patients not receiving a statin for comparative analysis of longitudinal outcomes.Results33/214 patients had a history of statin use. 63% started for primary prevention, while others were started for clinical ASCVD events, vascular surgery, IIM related heart failure, and cardiac transplantation. A high intensity statin was used in nine patients with non‐HMGCR myositis, and tolerated in 8/9 patients. Statin related muscular AE was noted in three patients. There were no cases of rhabdomyolysis, or statin related nonmuscular AEs in a median observation period of 5 years. In patients newly started on statins during cohort follow‐up (n = 7) there was no change in disease activity after statin initiation. Long term outcomes were not different between statin and nonstatin IIM control groups.ConclusionStatins were well tolerated in patients with non‐HMGCR positive IIM. Given the accelerated atherosclerotic risk in IIM patients, further prospective studies of statin safety in IIM patients are warranted.

Performance of the new EULAR/ACR classification criteria for idiopathic inflammatory myopathies (IIM) in a large monocentric IIM cohort

BackgroundIn 2017, the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) published new classification criteria for idiopathic inflammatory myopathies (IIM). ObjectivesTo [1] assess the performance of the EULAR/ACR criteria in a monocentric cohort of consecutive patients with IIM, compare them with the Bohan and Peter (BP) criteria, and with the physician's diagnosis; and [2] evaluate the effect of including the presence of interstitial lung disease (ILD) as variable in the criteria. Methods439 consecutive patients with a diagnosis of IIM followed at the Rheumatology Clinic, Karolinska University Hospital, Sweden were enrolled. The patients were diagnosed as IIM and subclassified by expert physicians. Clinical, laboratory, serological and histopathological data were collected from existing databases (Euromyositis registry and Swedish Rheumatology quality registry) and clinical charts of the patients. The sensitivity of the EULAR/ACR and the BP criteria was calculated. ResultsThe EULAR/ACR criteria had a higher sensitivity (87.7%) compared to the BP criteria (80.4%). The concordance between the two sets of criteria was low (k = 0.253 p<0.001). The EULAR/ACR criteria showed a very high specificity (>98%) for the major IIM subgroups polymyositis, dermatomyositis, and inclusion body myositis. The sensitivity was variable and was high in inclusion body myositis (98%), dermatomyositis (90%) and lower in polymyositis (73%). When including ILD in the variables of the criteria, six more patients were classified as IIM cases (1.3%). ConclusionThe EULAR/ACR criteria for IIM are applicable with high sensitivity and specificity using data available from existing databases and clinical charts and represent a major step forward from the previous criteria for IIM and its subgroups. Their application will improve the quality of clinical trials and research studies with IIM patients.

Acute Coronary Syndrome in Idiopathic Inflammatory Myopathies: A Population-based Study.

Evidence suggests an increased risk of cardiovascular (CV) diseases, including acute coronary syndrome (ACS), in idiopathic inflammatory myopathies (IIM). The aim of this study was to investigate the risk of ACS in an incident IIM cohort compared to the general Swedish population. A cohort of 655 individuals with incident IIM and 6813 general population comparators were identified from national registries. IIM subjects were diagnosed from 2002 to 2011. Followup started at IIM diagnosis and corresponding date in the general population. ACS, CV comorbidities, and CV risk factors were defined using International Classification of Diseases codes. Incidence rates including 95% CI were calculated. Cox proportional hazards models were used to compare the risk of ACS in patients with IIM and the general population. The competing risk of death was accounted for using competing risk regression models. The incidence rate of ACS in IIM was higher than in the general population, particularly within the first year of diagnosis and in older individuals. The overall ACS incidence rate in IIM was 15.6 (95% CI 11.7-20.4) per 1000 person-years, with an HR of 2.4 (95% CI 1.8-3.2) compared with the general population. When accounting for the competing risk of death, the risk of ACS in IIM remained increased with a cumulative incidence of 7% at 5 years compared to 3.3% in the general population. IIM individuals are at higher risk of ACS, particularly within the first year after diagnosis.

The performance of the European League Against Rheumatism/American College of Rheumatology idiopathic inflammatory myopathies classification criteria in an expert-defined 10 year incident cohort.

ObjectivesTo assess the performance of the EULAR/ACR idiopathic inflammatory myopathies (IIMs) classification criteria in a cohort of incident IIM cases and examine how criteria-assigned IIM subtype correlates with expert opinion.MethodsAdults with newly diagnosed IIM attending Salford Royal NHS Foundation Trust were identified over a 10 year period. A retrospective review of all putative cases was performed and those fulfilling a consensus expert opinion diagnosis of IIM were included. Clinical, serological and histological data were collected and each case was assigned a single IIM subtype. The EULAR/ACR classification criteria were then applied and sensitivity, specificity and positive and negative predictive values were calculated, presented with 95% CIs.ResultsA total of 1637 cases were screened, with 255 consensus expert opinion IIM cases ultimately identified. Applying the EULAR/ACR classification criteria, the sensitivity to diagnose an IIM was 99.6% (95% CI 97.2, 100) and 80.9% (95% CI 76.0, 85.8) for the criteria cut-points of probable and definite diagnoses, respectively. In 94/255 cases the IIM subtype differed between consensus expert opinion and classification criteria, most strikingly in the group subtyped as PM by the EULAR/ACR criteria, where there was discrepancy in the majority (i.e. in 87/161).ConclusionThe EULAR/ACR criteria performed with high sensitivity in identifying IIM in this external cohort of incident IIM. However, substantial disagreements arose between consensus expert opinion and the criteria regarding IIM subtype assignments, resulting in a large proportion of criteria-assigned cases of PM having heterogeneous features. These results may have important implications for future use of these criteria in subsequent research.

Venous Thromboembolic Events in Idiopathic Inflammatory Myopathy: Occurrence and Relation to Disease Onset.

To assess the incidence of venous thromboembolic events (VTEs) in patients with idiopathic inflammatory myopathies (IIMs), to compare the incidence of VTEs in IIM to the incidence in the general population, and to identify patient categories at high risk and investigate the development of risk in relation to a diagnosis of IIM. Using nationwide registers, we identified a cohort of 440 individuals with newly diagnosed IIM and 4,459 individuals from the general population. Patients with IIM were diagnosed between 2005 and 2011. The start of follow-up was the date of IIM diagnosis and the corresponding date in the general population. VTE was defined as hospital care with an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code indicating VTE, with a filled prescription for anticoagulant medication. Incidence rates including 95% confidence intervals (95% CIs) were calculated, and Cox proportional hazards models were used to compare the risk of VTE in patients with IIM to the risk in the general population. The incidence of VTEs was higher in patients with IIM than in the general population and was highest in patients who previously had cancer, who were ages >71 years when diagnosed with IIM, or who had dermatomyositis. The overall hazard ratio (HR) of VTE comparing the IIM cohort to the general population was 7.81 (95% CI 4.74, 12.85). The HR was highest the first year after IIM diagnosis, with HR 26.6 (95% CI 10.4, 68.0). Patients with IIM are at increased risk of VTE compared to the general population, especially during the first year after the diagnosis. Preventive measures should be focused on patients who previously have had cancer, who are ages >71 years when diagnosed, or who have dermatomyositis.

Mortality in idiopathic inflammatory myopathy: results from a Swedish nationwide population-based cohort study

Patients with idiopathic inflammatory myopathies (IIMs) suffer an increased burden of comorbidities, but data on mortality in recently diagnosed IIM are conflicting. Also, little is known when, if ever, in...

INVITED EDITORIAL COMMENT

<h3>Background</h3> Myositis-specific autoantibodies (MSA) are increasingly recognized as important diagnostic and prognostic markers in idiopathic inflammatory myopathies (IIM) (polymyositis, dermatomyositis, sporadic inclusion body myositis and necrotizing autoimmune myositis). The prevalence of these MSAs in other systemic autoimmune rheumatic diseases and neuromuscular diseases is unclear. <h3>Objectives</h3> To compare positivity of MSA in a cohort of IIM patients to positivity in healthy controls and different systemic autoimmune rheumatic diseases (SARD) or chronic inflammatory demyelinating polyneuropathy (CIDP). <h3>Methods</h3> A line immunoassay (Myositis 12 IgG DOT for BlueDiver) for IgG autoantibodies against Jo-1, PL-7, PL-12, EJ, SRP, Mi-2, MDA-5, TIF1-γ, HMGCR, SSA/Ro52kD, SAE1/2 and NXP-2 antigens was performed in patients with IIM (n=146), healthy controls (blood donors, n=40) and disease controls (n=200). The disease control group consisted of patients with other SARD (rheumatoid arthritis, RA; systemic sclerosis, Ssc; Sjögren9s syndrome, SjS; and systemic lupus erythematosus, SLE) (n=40 for each disease group) and CIDP (n=40). A result &gt;10 arbitrary units was considered significantly positive. <h3>Results</h3> 50% of 146 patients with IIM tested positive for an MSA (table 1), compared to 3,5% of 200 disease controls (table 1). 1 SSc patient was positive for Jo-1, 1 CIDP patient was positive for PL12, 2 SSc patients were positive for TIF1-gamma, 2 patients (1 SSc and 1 SjS patient) were positive for SAE1/2, and 1 SjS patient was positive for NXP2. The prevalence of SAE1/2 and TIF1-gamma positivity was similar in the IIM and disease control group. No healthy control had a significantly positive MSA. <h3>Conclusions</h3> MSA positivity in patients with a clinical non-IIM diagnosis (other SARD or CIDP) is infrequent compared to positivity in the IIM group. For TIF1-gamma and SAE1/2 assay performance may need to be optimized. The distribution of subtypes of MSA in this IIM cohort is consistent with data of previous studies.¹ <h3>References</h3> Allenbach Y, Benveniste O. Diagnostic Utility of Autoantibodies in Inflammatory Muscle Diseases. J Neuromuscul Dis. 2015; 2:13–25. <h3>Disclosure of Interest</h3> None declared

Dermatomyositis: the Asia-Pacific perspective

Dermatomyositis: the Asia-Pacific perspective