Hypothyroidism and dermato/polymyositis: a two-sample Mendelian randomization study.

Objective: Observational studies have revealed a higher probability of hypothyroidism in patients with dermatomyositis (DM) or polymyositis (PM), but there is no consensus on whether hypothyroidism causally influences DM or PM. In the present study, we assessed the causal association between hypothyroidism and the risk of dermatomyositis or polymyositis using two-sample Mendelian randomization (TSMR). Methods: The genome-wide association data of hypothyroidism and dermatomyositis/polymyositis were obtained from the IEU Open GWAS project. Then, TSMR was used to determine whether hypothyroidism is causally associated with DM or PM. Single-nucleotide polymorphisms (SNPs) significantly associated with hypothyroidism were identified and used as instrumental variables (IVs), and the causal relationship between hypothyroidism and DM/PM was examined using TSMR. MR pleiotropy and Cochran's Q test were used to confirm the heterogeneity and pleiotropy of identified IVs, then four different models, including the inverse variance weighted model (IVW), MR-Egger, weighted median and weighted model were applied in this MR analysis. Results: Sixty-eight SNPs for DM and 68 SNPs for PM were selected as the IVs (P<5×10-8; linkage disequilibrium R2 <0.001) to assess the causal association between hypothyroidism and DM/PM selected from GWASs on hypothyroidism. The results revealed a positive causal effect of hypothyroidism on both DM and PM (DM: OR 2.563, 95% CI [1.348, 4.874], P = 0.00156; PM: OR1.709, 95% CI [1.157, 2.525], P =0.007). Moreover, there was no heterogeneity or pleiotropy in the results. Conclusion: In conclusion, the MR analysis results provided strong evidence to indicate that hypothyroidism might be causally associated with DM and PM. These findings may have important implications for the pathogenesis and possible future therapies of DM/PM.

One case of spinal bulbar muscular atrophy misdiagnosed as polymyositis: Case report.

RATIONALE: Spinal bulbar muscular atrophy (SBMA) is a rare X-linked recessive motor neuron degenerative disease. Due to the lack of specificity in its early clinical manifestations, SBMA is easily misdiagnosed. Herein, we present a case in which SBMA was misdiagnosed as polymyositis. PATIENT CONCERNS: A 58-year-old patient began to develop symptoms of limb weakness 20 years ago and was admitted to the Second Hospital of Hebei Medical University 10 years ago without special treatment. Two years ago, the above symptoms worsened and he was admitted to Peking Union Medical College Hospital. The patient was misdiagnosed as polymyositis. According to the gene mutation characteristics of SBMA, the patient was diagnosed with SBMA. DIAGNOSES: The result of the Kennedy gene test was positive, and the patient was diagnosed with Kennedy disease. INTERVENTIONS: After the diagnosis of SBMA, the patient was given symptomatic treatment to alleviate the condition. OUTCOMES: Conservative treatment after discharge was requested. It is recommended that patients avoid bucking to prevent complications. LESSONS: This is a case of milder SBMA being misdiagnosed as polymyositis. For patients with weak limbs, the possibility of SBMA should be considered.

Atherosclerotic cardiovascular disease following a diagnosis of idiopathic inflammatory myopathy: analysis from a retrospective cohort in the TriNetX registry.

OBJECTIVE: Idiopathic inflammatory myopathies (IIM) confer an increased risk of morbidity from atherosclerotic cardiovascular disease (ASCVD). While ASCVD risk has been studied in other countries, these results may not be applicable to patients with dermatomyositis (DM) and polymyositis (PM) in the United States. This retrospective analysis of a cohort of patients identified by ICD code from TriNetX investigated the incidence of ASCVD after International Classification of Disease (ICD) codes of DM, PM, dermatopolymyositis (DPM) or juvenile dermatomyositis (JDM). METHOD: Patients were identified by entry of two ICD codes separated by at least 6 months, according to their first diagnosis code; ASCVD was defined as first ICD code for myocardial infarction, ischemic stroke, transient ischemic attack, or peripheral arterial disease. Cox proportional hazards regression modeled time from first IIM ICD code to ASCVD event. RESULTS: A total of 35,554 patients were identified with the mean age at first IIM code of 54 and 26.1% were male. The most common comorbidity for all groups except JDM was hyperlipidemia (39.9%) though 79.2% of patients were on no cholesterol lowering medication. ASCVD occurred in 30.4% of patients with PM, 24.3% of patients with DM and 0.9% of patients with JDM. Patients with PM had a median time to event of 9.7 years (95% Confidence interval (CI) 9.1, 10.7) and 14.3 years (95% CI 12.6, 14.8) for DM. This study demonstrates that ASCVD is a comorbidity occurring after a median of 12.5 years (95% CI 11.9, 13.6) in patients with IIM. CONCLUSIONS: ASCVD appears to be a long-term complication for IIM patients occurring in nearly a quarter of US patients without prior ASCVD with at least two ICD codes for IIM, with a median time to event of 12.5 years. There appears to be a practice gap in the recognition and treatment of hyperlipidemia in these patients. Key Points • Hyperlipidemia was a common comorbidity identified in patients with IIM though most patients were not on cholesterol lowering medication. • Development of ASCVD appears to be a long-term complication for patients with IIM in the United States.

Potential Mechanism and Therapeutic Targets of Polymyositis.

OBJECTIVE: To investigate the variability in the expression profile of genes associated with polymyositis (PM), explore the potential molecular mechanisms underlying PM, and predict novel targets for intervention. STUDY DESIGN: Descriptive study. Place and Duration of the Study: Department of Rheumatology, Taizhou Municipal Hospital, Taizhou, China, from August to November 2023. METHODOLOGY: Three microarray datasets (GSE3112, GSE39454, and GSE128470) were extracted from the gene expression omnibus (GEO). The analysis of this research involved identifying the differentially expressed genes (DEGs) in PM compared to normal samples. Enrichment analysis, gene-microRNA, gene-transcription factor (TF), and protein-protein interaction (PPI) network studies were conducted to identify hub genes and relevant pathways. Additionally, the drug-gene interaction database (DGIdb) was used to predict therapeutic medications. RESULTS: Eighty-eight DEGs were identified. The enrichment analysis results highlighted the significant involvement of downregulated DEGs in antigen processing and presentation. Based on the PPI networks, seven hub genes with high connectivity degrees were selected including a cluster of differentiation 74 (CD74), human leukocyte antigen (HLA)-DPA1, HLA-B, guanylate-binding protein 1 (GBP1), recombinant 2', 5'-oligoadenylate synthetase 1 (OAS1), HLA-C, and HLA-E. CONCLUSION: This research screened-out core genes, projected prospective therapeutic medications, discovered DEGs between PM and normal samples, and offered fresh perspectives for additional research into the possible mechanism and therapeutic targets of PM. KEY WORDS: Polymyositis, DEGs, Hub genes, Bioinformatics, Potential therapeutic agents.

The prevalence, epidemiological characteristics and mortality trends of inflammatory myopathies patients in Oman: the Prevision study.

OBJECTIVES: This research aims to investigate the prevalence, epidemiological characteristics, mortality rates, survival rates and the rate of malignancy in patients diagnosed with inflammatory myopathies (IIM) in Oman. METHODS: This is a longitudinal study, that covered a span of 16 years at eight rheumatology centres in Oman. The study included all adults and paediatric patients diagnosed with different types of idiopathic inflammatory myopathies (IIM) and who fulfil either the Bohan classification criteria or the 2017 EULAR/ACR classification criteria. RESULTS: The study included a total of 116 patient with an average age of 38.78 (±17.61 SD) years. The most prevalent form of myositis was found to be dermatomyositis (DM) 48 (41.38%), followed by polymyositis (PM) 36 (31.03%) and juvenile myositis (JDM) 18(15.52%). However, inclusion body myositis and necrotising myopathy were relatively rare conditions. The prevalence rates for DM, PM and JDM were determined as 2.2, 2.2, and 1.14 per 100,000 population respectively. Cardiac complications were observed in 14.66% of cases. Among the individuals studied, a history of malignancy was present in around 1.72% of cases. ANA antibodies were present in 71.55% of the cases, anti-Jo 1 and anti-RNP/SM antibodies were detected in 8.62%, and Anti-Ro antibodies in 24.14%. The overall mortality rate was found to be 6.90% with a rate of 11.1% among JDM cases. The five-year survival rates for PM, DM and JDM were found to be 94.4%, 91.7% and 89.0% respectively. These rates decline over a 10-year period to 67%, 69% and 83.3% respectively. CONCLUSIONS: The study highlights the prevalence, mortality, and survival rates of IIM in Oman. Patients with JDM had a higher mortality rate. This underscores the significance of using novel healthcare strategies to improve clinical outcomes and meet special requirements for this group of patients.

Value of radiomics-based automatic grading of muscle edema in polymyositis/dermatomyositis based on MRI fat-suppressed T2-weighted images.

BACKGROUND: The precise and objective assessment of thigh muscle edema is pivotal in diagnosing and monitoring the treatment of dermatomyositis (DM) and polymyositis (PM). PURPOSE: Radiomic features are extracted from fat-suppressed (FS) T2-weighted (T2W) magnetic resonance imaging (MRI) of thigh muscles to enable automatic grading of muscle edema in cases of polymyositis and dermatomyositis. MATERIAL AND METHODS: A total of 241 MR images were analyzed and classified into five levels using the Stramare criteria. The correlation between muscle edema grading and T2-mapping values was assessed using Spearman's correlation. The dataset was divided into a 7:3 ratio of training (168 samples) and testing (73 samples). Thigh muscle boundaries in FS T2W images were manually delineated with 3D-Slicer. Radiomics features were extracted using Python 3.7, applying Z-score normalization, Pearson correlation analysis, and recursive feature elimination for reduction. A Naive Bayes classifier was trained, and diagnostic performance was evaluated using receiver operating characteristic (ROC) curves and comparing sensitivity and specificity with senior doctors. RESULTS: A total of 1198 radiomics parameters were extracted and reduced to 18 features for Naive Bayes modeling. In the testing set, the model achieved an area under the ROC curve of 0.97, sensitivity of 0.85, specificity of 0.98, and accuracy of 0.91. The Naive Bayes classifier demonstrated grading performance comparable to senior doctors. A significant correlation (r = 0.82, P <0.05) was observed between Stramare edema grading and T2-mapping values. CONCLUSION: The Naive Bayes model, utilizing radiomics features extracted from thigh FS T2W images, accurately assesses the severity of muscle edema in cases of PM/DM.

Pretreatment mortality risk prediction model in patients with polymyositis/dermatomyositis-associated interstitial lung disease.

OBJECTIVES: Risk prediction for patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD) is challenging due to heterogeneity in the disease course. We aimed to develop a mortality risk prediction model for PM/DM-ILD. METHODS: This prognostic study analysed patients with PM/DM-ILD admitted to Nanjing Drum Hospital from 2016 to 2021. The primary outcome was mortality within 1 year. We used a least absolute shrinkage and selection operator (LASSO) logistic regression model to identify predictive laboratory indicators. These indicators were used to create a laboratory risk score, and we developed a mortality risk prediction model by incorporating clinical factors. The evaluation of model performance encompassed discrimination, calibration, clinical utility and practical application for risk prediction and prognosis. RESULTS: Overall, 418 patients with PM/DM-ILD were enrolled and randomly divided into development (n=282) and validation (n=136) cohorts. LASSO logistic regression identified four optimal features in the development cohort, forming a laboratory risk score: C reactive protein, lactate dehydrogenase, CD3+CD4+ T cell counts and PO2/FiO2. The final prediction model integrated age, arthralgia, anti-melanoma differentiation-associated gene 5 antibody status, high-resolution CT pattern and the laboratory risk score. The prediction model exhibited robust discrimination (area under the receiver operating characteristic: 0.869, 95% CI 0.811 to 0.910), excellent calibration and valuable clinical utility. Patients were categorised into three risk groups with distinct mortality rates. The internal validation, sensitivity analyses and comparative assessments against previous models further confirmed the robustness of the prediction model. CONCLUSIONS: We developed and validated an evidence-based mortality risk prediction model with simple, readily accessible clinical variables in patients with PM/DM-ILD, which may inform clinical decision-making.

[Magnetic resonance imaging T2 mapping could reflect disease status in patients with dermatomyositis or polymyositis].

This study aimed to explore the value of magnetic resonance imaging (MRI) T2 mapping in the assessment of dermatomyositis (DM) and polymyositis (PM). Thirty-three confirmed cases (myosin group) and eight healthy volunteers (healthy control group) at the Department of Rheumatology and Immunology, the First Affiliated Hospital of Kunming Medical University, from October 2016 to December 2017, were collected and analyzed. Multiple parameters of the myosin group were quantified, including creatine kinase (CK), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement C3, and complement C4. Disease status was evaluated using a panel of tools: myositis disease activity assessment tool-muscle (MDAAT-muscle), myositis disease activity assessment tool-whole (MDAAT-all), health assessment questionnaire (HAQ), medical outcomes study health survey short form-36 item (SF-36), hand muscle strength test (MMT-8) score, and MRI T2 mapping of muscle (22 muscles in the pelvis and thighs) T2 values. The results showed that in the myositis group, the measurements for CK, ESR, CRP, complement C3, and complement C4 were 457.2 (165.6, 1 229.2) IU/L, 20 (10, 42) mm/1h, 3.25 (2.38, 10.07) mg/L, 0.90 (0.83, 1.06) g/L, and 0.18 (0.14, 0.23) g/L, respectively. The scores for MMT-8, MDAAT-muscle, MDAAT-all, HAQ, and SF-36 were 57.12±16.23, 5.34 (4.00, 6.00), 34.63±12.62, 1.55 (0.66, 2.59), and 44.66±7.98, respectively. T2 values were significantly higher in all 22 muscles of the pelvis and thighs of patients with DM or PM compared with the healthy controls [(54.99±11.60)ms vs. (36.62±1.66)ms, P<0.001], with the most severe lesions in the satrorius, iliopsoas, piriformis, gluteus minimus, and gluteus medius muscles. The total muscle T2 value in the myositis group was positively correlated with CK, MDAAT-muscle, MDAAT-all, and HAQ (r=0.461, 0.506, 0.347, and 0.510, respectively, all P<0.05). There was a negative correlation between complement C4, SF-36, and MMT-8 scores (r=-0.424, -0.549, and -0.686, respectively, all P<0.05). Collectively, the findings from this study suggest that MRI T2 mapping can objectively reflect the disease status of DM and PM.

Therapeutic efficacy and safety of JAK inhibitors in treating polymyositis/dermatomyositis: a single-arm systemic meta-analysis.

Introduction: We performed a single-arm meta-analysis to evaluate the efficacy and safety of JAK inhibitors in the treatment of dermatomyositis (DM)/ polymyositis (PM). Methods: Relevant studies from four databases were systematically searched until April 25, 2023. The primary endpoint was Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) and other outcomes were Manual Muscle Testing (MMT) and Creatine Kinase (CK). According to the type of JAK and medication regimen, we conducted subgroup analyses. The registration number in PROSPERO was CRD42023416493. Results: According to the selection criteria, we identified 7 publications with a total of 91 patients. Regarding skin lesions, the CDASI decreased by 17.67 (95% CI: -20.94 ~ -14.41). The CK increased by 8.64 U (95% CI: -28.25 ~ 45.53). About muscle lesions, MMT increased by 10.31 (95% CI: -2.83 ~ 23.46). Subgroup analysis revealed that different types of JAK inhibitors had various degrees of reduction. CDASI in patients treated with RUX had the lowest one [-20.00 (95% CI: -34.9 ~ -5.1)], followed by TOF [-18.29 (95% CI: -21.8 ~ -14.78)] and BAR [-11.2 (95% CI: -21.51 ~ -0.89)]. Additionally, the mean reduction in CDASI in patients treated with TOF alone was 16.16 (95% CI: -21.21 ~ -11.11), in combination with other immunosuppressants was 18.59 (95% CI: -22.74 ~ -14.45). For safety evaluation, one patient developed Orolabial HSV, and two patients developed thromboembolism events. Discussion: In summary, this meta-analysis demonstrated that JAK inhibitors can potentially treat DM/PM without severe adverse reactions. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42023416493, identifier CRD42023416493.

Quantitative whole-body muscle MRI in idiopathic inflammatory myopathies including polymyositis with mitochondrial pathology: indications for a disease spectrum.

OBJECTIVE: Inflammatory myopathies (IIM) include dermatomyositis (DM), sporadic inclusion body myositis (sIBM), immune-mediated necrotizing myopathy (IMNM), and overlap myositis (OLM)/antisynthetase syndrome (ASyS). There is also a rare variant termed polymyositis with mitochondrial pathology (PM-Mito), which is considered a sIBM precursor. There is no information regarding muscle MRI for this rare entity. The aim of this study was to compare MRI findings in IIM, including PM-Mito. METHODS: This retrospective analysis included 41 patients (7 PM-Mito, 11 sIBM, 11 PM/ASyS/OLM, 12 IMNM) and 20 healthy controls. Pattern of muscle involvement was assessed by semiquantitative evaluation, while Dixon method was used to quantify muscular fat fraction. RESULTS: The sIBM typical pattern affecting the lower extremities was not found in the majority of PM-Mito-patients. Intramuscular edema in sIBM and PM-Mito was limited to the lower extremities, whereas IMNM and PM/ASyS/OLM showed additional edema in the trunk. Quantitative assessment showed increased fat content in sIBM, with an intramuscular proximo-distal gradient. Similar changes were also found in a few PM-Mito- and PM/ASyS/OLM patients. In sIBM and PM-Mito, mean fat fraction of several muscles correlated with clinical involvement. INTERPRETATION: As MRI findings in patients with PM-Mito relevantly differed from sIBM, the attribution of PM-Mito as sIBM precursor should be critically discussed. Some patients in PM/ASyS/OLM and PM-Mito group showed MR-morphologic features predominantly observed in sIBM, indicative of a spectrum from PM/ASyS/OLM toward sIBM. In some IIM subtypes, MRI may serve as a biomarker of disease severity.

Prevalence of hearing loss, tinnitus, vertigo and sudden deafness among patients with polymyositis and dermatomyositis.

Little is known about a possible association of autoimmune inner ear disease among patients diagnosed with polymyositis (PM)/dermatomyositis (DM). This study aimed to explore differences in the prevalence of inner ear symptoms among patients with and without PM/DM using a nationwide population-based dataset. Data for this study were retrieved from the Taiwan National Health Insurance Research Database. The study sample included 1622 patients diagnosed with PM/DM and 8109 propensity-score matched comparison patients without PM/DM. We performed multivariate logistic regressions to calculate odds ratios (ORs) and 95% confidence interval (CI) for tinnitus, hearing loss, sudden deafness, and vertigo among patients with PM/DM versus comparison patients. Chi-square tests showed statistically significant differences between patients with PM/DM and comparison patients in the prevalence of tinnitus (16.1% vs. 12.7%, p < 0.001), non-conductive hearing loss (9.2% vs. 6.8%, p < 0.001), and vertigo (14.4% vs. 11.1%, p < 0.001). The adjusted ORs for tinnitus, non-conductive hearing loss, and vertigo, respectively, were 1.332 (95% CI = 1.147-1.547), 1.399 (95% CI = 1.154-1.696), and 1.374 (95% CI = 1.173-1.611) for patients with PM/DM when compared to comparison patients. Our study finds that patients with PM/DM have higher prevalence rates of tinnitus, non-conductive hearing loss, and vertigo than comparison patients.

Evaluating disease status in idiopathic inflammatory myopathies with quantitative muscle ultrasound.

INTRODUCTION/AIMS: Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients. METHODS: Patients with IIM, excluding inclusion body myositis, were recruited along with age- and sex-matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures. RESULTS: Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing-8. DISCUSSION: Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.

Intravoxel Incoherent Motion Diffusion-Weighted MRI, Fat Quantification, and Electromyography: Correlation in Polymyositis and Dermatomyositis.

(1) Background: The intravoxel incoherent motion (IVIM) model can provide information about both molecular diffusion and blood flow for the evaluation of skeletal muscle inflammation. MRI-based fat quantification is advantageous for assessing fat infiltration in skeletal muscle. (2) Purpose: We aimed to quantitatively measure various parameters associated with IVIM diffusion-weighted imaging (DWI) and fat quantification in the muscles of patients with polymyositis and dermatomyositis using magnetic resonance imaging and to investigate the relationship between these parameters and electromyography (EMG) findings. (3) Material and methods: Data were retrospectively evaluated for 12 patients with polymyositis and dermatomyositis who underwent thigh MRI, including IVIM-DWI and fat quantification. The IVIM-derived parameters included the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f). Fat fraction values were assessed using the six-point Dixon technique. Needle EMG was performed within 9 days of the MRI. (4) Results: The f values (19.02 ± 4.87%) in muscles with pathological spontaneous activity on EMG were significantly higher than those (14.60 ± 5.31) in muscles without pathological spontaneous activity (p < 0.027). There were no significant differences in D, D*, ADC, or fat fraction between muscles with and without pathologic spontaneous activity. Significant negative correlations were observed between fat fraction and amplitude (r = -0.402, p < 0.015) and between fat fraction and duration (r = -0.360, p < 0.031). (5) Conclusion: The current study demonstrates that IVIM-DWI and fat quantification using 3.0 T MRI may aid in predicting EMG findings in patients with polymyositis and dermatomyositis and promote the pathophysiological study of idiopathic inflammatory myopathies.

Polymyositis is a rare and favourable outcome subtype of idiopathic inflammatory myopathy in Chinese patients.

OBJECTIVES: To investigate the prevalence and characteristics of typical polymyositis (PM) in Chinese patients with idiopathic inflammatory myopathy (IIM). METHODS: Patients diagnosed with IIM according to the 2017 EULAR/ACR criteria were included. Serological aspects including myositis-specific antibodies (MSA) and pathological data were re-evaluated. The diagnosis of typical PM was strictly done using the pathological criteria, while excluding other IIM subtypes such as dermatomyositis (DM), immune-mediated necrotising myopathies (IMNM), anti-synthetase syndrome (ASS), and sporadic inclusion body myositis (sIBM), based on their respective diagnostic criteria. RESULTS: A total of 544 IIM patients with muscle biopsy were involved, and 129 of them were diagnosed with initial PM according to the 2017 EULAR/ACR criteria. Only 6 (1.1%, 6/544) patients met the strict definition of typical PM after re-evaluation. Patients with typical PM were MSA-negative (100% vs. 35.7%, p=0.003) and had CD8+ T cells surrounding or invading non-necrotic muscle fibres in muscle biopsies (100% vs. 7.8%, p<0.001) compared to the initially diagnosed PM patients. All typical PM patients achieved clinical remission at the second-year follow-up. Typical PM patients had a favourable prognosis compared to MSA-negative IMNM and unspecific myositis patients. CONCLUSIONS: Strictly defined typical PM is a rare clinical subtype in Chinese IIM patients. Typical PM patients with classical pathology were MSA-negative and responded well to treatment and had a favourable prognosis. It is crucial for clinicians to combine clinical, serological, and pathological features to properly distinguish PM from other IIM subtypes.

Cancer Risk and Mortality in Hospitalized Patients With Idiopathic Inflammatory Myopathies in Western Australia.

OBJECTIVE: To compare cancer incidence, type, and survival between patients with idiopathic inflammatory myopathies (IIMs) in Western Australia (WA) and the general population. METHODS: Administrative health data for hospitalized patients with incident IIM (n = 803, 56.5% female, median age 62.0 yrs), classified by a validated algorithm as polymyositis (PM; 36.2%), dermatomyositis (DM; 27.4%), inclusion body myositis (IBM; 17.1%), overlap myositis (OM; 10.7%), and other IIM (8.6%), were linked to WA cancer and death registries for the period of 1980 to 2014. Cancer incidence rates (CIRs) before and after IIM diagnosis as well as cancer mortality were compared with age-, sex-, and calendar year-matched controls (n = 3225, 54.9% female, median age 64 yrs) by rate ratios (RRs) and Kaplan-Meier survival estimates. RESULTS: The prediagnosis CIR was similar for patients with IIM and controls (6.57 vs 5.95; RR 1.11, 95% CI 0.88-1.39) and for patients evolving to DM (n = 220) or other IIM subtypes (6.59 vs 6.56; RR 1.01, 95% CI 0.38-3.69). During follow-up, CIR was higher for all DM (4.05, 95% CI 3.04-5.29), with increased CIR for lung cancer vs controls (1.05 vs 0.33; RR 3.18, 95% CI 1.71-5.47). Cancer post diagnosis shortened life span by 59 months for patients with IIM (103 vs 162 months, P < 0.01), but reduced survival rates were observed only in patients with DM and IBM. CONCLUSION: Cancer risk was not increased prior to IIM, but CIR for lung cancer was increased following DM diagnosis. As cancer reduced survival only in patients with DM and IBM, these data support a strategy of limited cancer screening in IIM.

Myxovirus resistance protein A (MxA) expression in myositides: Sarcoplasmic expression is common in both dermatomyositis and lupus myositis.

INTRODUCTION/AIMS: Myxovirus resistance protein A (MxA) is a type I interferon (IFN1) pathway activation marker and MxA sarcoplasmic expression is currently recognized as a highly specific marker for dermatomyositis (DM). However, we have frequently observed endothelial tubuloreticular inclusions (TRI), another surrogate IFN1 activation marker, in a variety of overlap myositides. The aim of this study was to examine MxA expression in those myositides. METHODS: We retrospectively performed MxA immunostaining on a wide range of myositides. RESULTS: MxA sarcoplasmic expression was present in DM (94.4%, 17/18), active lupus myositis (LM, 80%,16/20), inactive LM (36%, 4/11), antisynthetase syndrome (ASyS, 20%, 2/10), systemic sclerosis (13%, 2/15), Sjogren's syndrome (7.7%, 1/13), and human immunodeficiency virus (HIV) myositis (5.6%, 1/18) and was absent in immune-mediated necrotizing myopathy (IMNM, 0/16) and hydroxychloroquine myopathy (0/5). The sensitivity and specificity of MxA sarcoplasmic expression for LM and DM combined compared with all other myositides were 84.6% (95% CI: 69.5-94.1) and 92.1 (95% CI: 83.6-97.0), respectively, and superior to TRIs. MxA capillary expression was nonspecific. Histologically, 35% of LM cases demonstrated a unique panfascicular necrotizing myopathy pattern. The remainder of the LM cases had significant morphological overlap with DM/ASyS (20%), IMNM (20%), or polymyositis (15%). DISCUSSION: MxA sarcoplasmic expression is highly prevalent in LM and DM and is a useful marker in differentiating DM and LM from other myositides. LM can manifest in various pathology patterns that need to be differentiated from DM, IMNM, ASyS, and polymyositis.

A bibliometric analysis of the research status and trends in studies on polymyositis and dermatomyositis with interstitial lung disease from 2000 to 2022 using Web of Science.

BACKGROUND: The main subtypes of idiopathic inflammatory myopathies (IIMs)-polymyositis (PM) and dermatomyositis (DM)-are often presented as interstitial lung disease (ILD) in clinical practice; therefore, many researchers have combined the three studies into PM/DM with ILD. METHODS: Using bibliometrics, the research status, progress, and hotspots of PM/DM with ILD between 2000 and 2022 were studied. Literature data on PM/DM with ILD were retrieved from the Web of Science (WoS) database for the research period. Visualization software, including VOSviewer, Pajek, CiteSpace, and Scimago Graphica were used for bibliometric analysis. RESULTS: A total of 1555 relevant articles were obtained, and the overall research in this field showed an increasing trend. Regarding contributing countries and venues, Japan published the most articles while Rheumatology was the most prolific journal. Regarding authors, the most published article was by Wang Guochun from Changchun University of Technology in China. Keyword analysis and cocited literature cluster analysis showed that diagnosis, classification, autoantibodies, antibodies, prognosis, complications, and treatment of PM/DM with ILD have been hot topics in this field recently. Moreover, our study shows that anti-mda5 antibody, mortality, gene 5 antibody, IIMs, double-blind, and prognostic factors, among others, may be new hot topics. CONCLUSION: This study found that research on PM/DM with ILD has increased over time, and scholars are paying more attention to this field. The development of new drugs for the management, treatment, and prevention of PM/DM with ILD is the primary task of researchers and a direction for future research in this field.

Burkholderia-associated polymyositis.

A diagnosis of polymyositis can readily be made when there is a typical history of proximal muscle weakness together with clinical findings, and there is corroboratory evidence in the form of elevated creatine kinase lactate dehydrogenase, aldolase, and serum glutamic-oxaloacetic transaminase (aspartate aminotransferase). A muscle biopsy usually helps in making the confirmatory diagnosis. A female in her 50s presented with non-healing multiple deep necrotic ulcers with muscle weakness. The initial possibility of vasculitis ulcers remained. Later, this proved to be a case of polymyositis with mildly elevated creatine kinase (which is usually not the case), atypical skin manifestations (usually there is no skin involvement), and negative extended myositis specific antibody panel with the growth of Burkholderia cepacia (perhaps the triggering factor). Hence, polymyositis can present with a myriad of atypical findings. Thus, thorough clinical examination and an integrated approach are necessary for early identification and treatment of the disease.

Increased Rate of Complications Following Total Knee Arthroplasty in Patients Who Have Polymyositis.

BACKGROUND: Polymyositis (PM) is a systemic connective tissue disorder that can lead to early onset degenerative joint disease and a need for total knee arthroplasty (TKA). Outcomes of TKA in patients who have PM are not well documented in the literature. The purpose of this study was to evaluate PM as a risk factor for complications after TKA. METHODS: Using a national private payer insurance database from 2010 to 2022, PM patients undergoing primary TKA were compared to 10:1 matched controls based on age, sex, and comorbidities. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. 90-day emergency department visits and inpatient readmissions were also documented. A total of 25,039 patients undergoing primary TKA were queried, of which 2,290 had PM. RESULTS: Compared to the matched controls, patients who had PM demonstrated higher rates of medical and surgical complications, including pulmonary embolism (1.0% versus 0.5%, P = .001), cerebrovascular accident (1.3% versus 0.7%, P = .002), wound complications (3.4% versus 2.1%, P < .001), and periprosthetic joint infection at 1 year (1.7% versus 1.3%, P = .042) and 2 years (2.6% versus 1.9%, P = .006). Patients who had PM displayed elevated 90-day emergency department (14.9% versus 13.3%, P = .032) and hospital readmission rate (7.1% versus 4.8%, P < .001). CONCLUSIONS: Patients who have PM are at higher risks of postoperative medical and surgical complications, including pulmonary embolism, cerebrovascular accident, wound complication, and periprosthetic joint infection. Given these results, it is helpful for orthopedic surgeons and patients to consider these risks when considering TKA for patients who have PM.