Clinical, electrophysiologic, and histopathologic profile, and outcome in idiopathic inflammatory myositis: An analysis of 68 cases

Exploring the link between inflammatory myopathies and cancer: A comprehensive retrospective analysis in a Colombian cohort

BACKGROUND

This study investigates the association between inflammatory myopathies (IM), and their correlation with cancer. There are several potential causes behind the association of cancer and inflammatory myopathies. The positivity of specific antibodies for myositis plays a significant role. Our objective is to describe cancer and inflammatory myopathies in Colombia, focusing on demographics, clinical characteristics, and laboratory data.

METHODS

We retrospectively analyzed 112 IM patients diagnosed at Fundación Valle del Lili in Cali, Colombia, the cases met the EULAR/ACR criteria. Data included demographics, clinical signs, laboratory findings, and malignancy. Malignancy associations were explored using logistic regression. The survival analysis was assessed using Kaplan-Meier curves and the Log-Rank test.

RESULTS

Dermatomyositis was the most common subtype (45.5%), with a female predominance (66.1%). Cancer diagnosis occurred in 11.6% of cases, predominantly thyroid cancer. The median time from myopathy onset to cancer diagnosis was 11 months, with 75% of cases within the first year. Bivariate analysis indicated associations between cancer and age, Gottron's papules, digital ulcers, and heliotrope rash. However, multivariate analysis identified age as the only significant malignancy risk factor. Survival analysis showed better rates in younger patients.

CONCLUSION

This study provides into the link between IM and cancer in the Colombian population. Thyroid cancer predominated, with a slightly higher proportion of female cancer diagnoses. Age emerged as a significant risk factor for malignancy. Understanding this association is crucial for early detection and improving patient outcomes related to IM-associated malignancies.

Long Term Outcomes in Idiopathic Inflammatory Myositis: An Observational Epidemiologic Study over 15 Years

Background

We report a longitudinal observational cohort of idiopathic inflammatory myositis (IIM) focusing on the long-term clinical outcome and associated parameters.

Methods

IIM patients were classified as per Bohan and Peter criteria. In those with ≥ 24 months of follow-up; the treatment response, functional outcomes, and damage at last follow-up were recorded. Complete clinical response and clinical remission as defined by Oddis et al., was used to define outcomes at last follow-up.

Results

The cohort consists of 175 patients, mean age 40.9 (+12.6) years, M:F 1:3.3; and the major subsets were dermatomyositis (44.6%), overlap myositis (25.7%), antisynthetase syndrome (6.3%), polymyositis (14.3%), and juvenile DM/OM (8.6%). Ninety-four patients have followed up for 24 months or more, with the median (IQR) of 65(35,100.7) months. Of them, 74.1% and 11.8% had complete and partial clinical responses respectively at the last follow-up. In our cohort 40.2% were off-steroids and 13.8% were in clinical remission at the last follow-up. Complete clinical response was associated with better functional outcomes and lesser damage as determined by HAQ-DI of 0[OR10.9; 95%CI (3.3,160)], MRS [OR 3.2; 95%CI (1.4,7.3)] and lesser MDI [OR 1.7; 95% CI (1.1,2.7)] respectively as compared to partial response (unadjusted analysis). Baseline parameters and IIM subsets did not significantly influence the functional outcome and damage. The mortality rate in our cohort is 24/175 (13.7%), the disease-specific mortality rate being 9.1%. Large majority of deaths were early, associated with active disease.

Conclusion

We report good long-term outcomes in all major myositis subsets. Partial clinical response to treatment is associated with worse functional outcomes and damage accrual. Death occurs early in association with active disease.

Observational longitudinal study to assess the outcome of patients with idiopathic inflammatory myositis using validated tools

INTRODUCTION

There have been major changes in the classification and treatment of patients with idiopathic inflammatory myositis (IIM) in the last 2 decades. A major challenge is to identify the parameters that can affect the outcome and prognosis of these patients. Here, we have longitudinally followed a well-characterized cohort of IIM patients in a rheumatology center and reported the outcome using the validated tools.

METHOD

Patients with a clinical diagnosis of IIM and a follow-up duration of greater than 2 years were prospectively included in the study. The duration of the study was 6 years: July 2016-July 2022. Clinical details and follow-up were recorded using pro-formas and outcomes were noted using validated tools. Ethics approval and written informed consent were taken.

RESULTS

Forty patients had a clinical diagnosis of IIM. Mean follow-up duration was 43.8 (15) months. Out of 40 patients, 32 (80%) achieved remission (8 patients each were off corticosteroid and off treatment for >6 months), 5 (12%) expired and 3 (8%) had active disease. Disease course was non-relapsing in 22/35 (73%) patients. Mean manual muscle testing-8 score (n = 29) and myositis disease activity assessment tool score (n = 35) at the final visit were 75.6 (6.8) and 0.048 (0.07) respectively. Thirteen patients had damage (37%). Patients with disease duration >1 year at the time of presentation were more likely to develop chronic-continuous disease course (P = .023, odds ratio [OR] = 7.6), more frequently required second-line or third-line immunosuppression (P = .001, OR = 24) with higher myositis damage index score (p = .0002, OR = 47).

CONCLUSIONS

IIM patients had good outcomes with the majority achieving remission and near-complete muscle recovery. However, the patients presenting late to the rheumatologists were more likely to have smoldering disease, more immunosuppressive medicines, and greater accumulated damage.

Joint and muscle inflammatory disease: A scoping review of the published evidence

OBJECTIVES

Polyarthritis is commonly reported in idiopathic inflammatory myositis patients, but few studies have focused on the overlap of myositis with rheumatoid arthritis which is a difficult diagnosis in the absence of well-defined diagnostic criteria. The primary objective of this scoping review was to map the field of research to explore the potential diagnoses in patients presenting with both myositis and polyarthritis.

METHODS

Two electronic databases (MEDLINE/PubMed® and Web of Science®) were systematically searched using the terms (myositis OR 'inflammatory idiopathic myopathies') AND (polyarthritis OR 'rheumatoid arthritis') without any publication date limit.

RESULTS

Among individual records, 280 reports met inclusion criteria after full-text review. There was heterogeneity in the definition of overlap myositis as well as the characteristics of rheumatoid arthritis. In many studies, key data were lacking; rheumatoid factor status was reported in 56.8% (n=151), anti-citrullinated proteins antibodies status in 18.8% (n=50), and presence or absence of bone erosions in 45.1% (n=120) of the studies. Thirteen different diagnoses were found to associate myositis with polyarthritis: antisynthetase syndrome (29.6%, n=83), overlap myositis with rheumatoid arthritis (16.1%, n=45), drug-induced myositis (20.0%, n=56), rheumatoid myositis (7.5%, n=21), inclusion body myositis (1.8%, n=5), overlap with connective tissue disease (20.0%, n=56), and others (5.0%, n=14).

CONCLUSION

The spectrum of joint and muscle inflammatory diseases encompasses many diagnoses including primitive and secondary myositis associated with RA or arthritis mimicking RA. This review highlights the need for a consensual definition of OM with RA to better individualise this entity from the numerous differential diagnoses.

Clinical and laboratory characteristics of idiopathic inflammatory myositis in Saudi patients: A retrospective study in a single tertiary centre

OBJECTIVES

Idiopathic inflammatory myositis (IIM) in Saudi patients has been poorly studied owing to the lack of available data. This study aimed to identify the clinical and laboratory features of patients at a single tertiary care center.

METHODS

This retrospective study reviewed the medical records of Prince Sultan Military Medical City, Riyadh, Saudi Arabia to collect clinical and laboratory data between December 2022 and February 2017 as follows: age at disease onset, gender, follow-up duration and disease duration; clinical symptoms; laboratory result; presence and type of myositis-specific autoantibody or myositis-associated autoantibody; and type of immunosuppression, presence of malignancy, disease course, and outcome.

RESULTS

There were 26 patients with a mean age of 36.16±13.48, and 84.6% were women. The most prevalent form of IIM was dermatomyositis (n=16, 61.5%), and the most affected organ was the skin. weakness was observed in 25 patients (96.2%), and dysphagia was the most common alarm sign (n=10, 38.5%). During follow-up, the creatine kinase level was elevated at the beginning of the disease and then decreased following treatment, with a mean of 277.73 IU/L. Of the total patients, 17 (68%) were positive for anti-nuclear antibody and 5 (19.2%) were positive for anti-Jo-1.

CONCLUSION

In our patients, dermatomyositis was the most common form of myositis, and skin manifestations were the most prevalent clinical characteristics. None of the patients developed a malignancy or died.

Clinical, Serological, and Genetic Characteristics of a Hungarian Myositis-Scleroderma Overlap Cohort

Overlap myositis is a distinct subgroup of idiopathic inflammatory myositis (IIM) with various clinical phenotypes. The aim of this study was to determine the clinical, serological, and genetic features of systemic sclerosis (SSc)-IIM overlap patients. It was a retrospective study using clinical database of 39 patients, fulfilling both the criteria of SSc and IIM. 56.4% of the patients had limited cutaneous, 43.6% had diffuse cutaneous SSc, whereas 7.7% of the patients had dermatomyositis and 92.3% polymyositis. The two diseases occurred simultaneously in 58.97%, while 10.26% in myositis and 30.77% in scleroderma were initially diagnosed. The frequencies of organ involvement were interstitial lung disease 71.8%, dysphagia 66.7%, cardiac involvement 41%, pulmonary arterial hypertension (PAH) 30.8%, and renal involvement 12.8%, respectively. The presence of human leukocyte antigen (HLA) − DRB1∗03 and DQA1∗051∗01 alleles were significantly higher in the overlap patients than in healthy controls (82.35% vs. 27.54%; p < 0.0001 and 88.24% vs. 30.16; p < 0.0001). Certain clinical parameters, such as fever at diagnosis (41.67% vs. 7.41%, p = 0.0046), cardiac involvement (83.33% vs. 22.22%, p = 0.0008), subcutaneous calcinosis (41.66 vs. 11.11, p = 0.01146), and claw hand deformity (25% vs. 11.11%, p = 0.00016) were significantly associated with the presence of PAH. Upon comparison, the overlap patients and anti-Jo-1 positive antisynthetase patients showed similarities in terms of genetic results and major clinical features; however, SSc-IIM overlap patients could be distinguished with higher erythrocyte sedimentation rate (ESR) level, more frequent presence of Raynaud's phenomenon (p < 0.0001; OR: 20.00), dysphagia (p < 0.0001; OR: 15.63), and infrequent livedo reticularis (p < 0.01; OR: 0.11). SSc-IIM overlap myositis is a unique group within IIM-s possessing characteristic clinical features.

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.

Antisynthetase syndrome: A distinct disease spectrum

The discovery of novel autoantibodies related to idiopathic inflammatory myopathies (collectively referred to as myositis) has not only advanced our understanding of the clinical, serological, and pathological correlation in the disease spectrum but also played a role in guiding management and prognosis. One group of the myositis-specific autoantibodies is anti-aminoacyl-tRNA synthetase (anti-ARS or anti-synthetase) which defines a syndrome with predominant interstitial lung disease, arthritis, and myositis. Autoantibodies to eight aminoacyl-tRNA synthetases have been identified with anti-Jo1 the most common in all of idiopathic inflammatory myopathies. Disease presentation and prognosis vary depending on which anti-aminoacyl-tRNA synthetase antibody is present. In this review, we will discuss the clinical characteristics, overlap features with other autoimmune diseases, prognostic factors, and management of the antisynthetase syndrome.

The spectrum of idiopathic inflammatory myopathies in South Africa

INTRODUCTION

There are many reports on idiopathic inflammatory myopathies (IIM) but little information from sub-Saharan Africa. We conducted a retrospective study of IIM in a multi-ethnic cohort seen at a single centre in Durban, South Africa.

METHOD

The study included patients who fulfilled the Bohan and Peter or European League Against Rheumatism/American College of Rheumatology criteria for IIM. The information recorded included demographic data, clinical findings, results of investigations, treatment and outcome. Patients with overlap myositis (OM) had myositis and criteria for another connective tissue disease.

RESULTS

There were 104 patients with IIM; 82.7% female and 70.2% African blacks. They included 41 (39.4%) with OM, 26 (25%) polymyositis (PM), 26 (25%) dermatomyositis (DM), six (5.8%) juvenile dermatomyositis and five (4.8%) cancer-associated myositis. Our patients had a younger mean age at diagnosis (36.8 ± 14.7 years) compared with 45-55 years in most other studies. Scleroderma-myositis overlap accounted for 26 (63.4%) of the patients with OM. Patients with OM were significantly younger than PM (p = 0.004) and DM (p = 0.044) and had lower, but not statistically significant, creatine kinase levels at diagnosis compared with PM (p = 0.052) and DM (p = 0.073). Interstitial lung disease was more common in OM (p = 0.001) and PM (p = 0.024) than DM. Oropharyngeal weakness was more common in DM than OM (p = 0.001) and PM (p = 0.032). African blacks were younger (p = 0.028) at diagnosis and had more cardiac abnormalities (p = 0.034) than Indians.

CONCLUSION

The spectrum of IIM in our cohort of mainly African blacks is similar to other studies, with OM being the most frequent subtype. Key Points • As there is limited information on idiopathic inflammatory myopathies (IIM) in sub-Saharan Africa, this study reports the spectrum of IIM in a South African cohort of predominantly African blacks. • Our patients were younger at diagnosis, and overlap myositis was the most common phenotype. • Comparisons with other studies show similarities in the manifestations of IIM.

Prevalence of other connective tissue diseases in idiopathic inflammatory myopathies

We sought to determine the prevalence of additional connective tissue diseases (CTDs) in patients with idiopathic inflammatory myopathies (IIM), and to study the muscle biopsy patterns in various clinico-serologic subsets of myositis. We undertook a retrospective cohort study of 648 patients with a histological diagnosis of IIM. The following was determined from the South Australian Myositis Database: presence of associated CTDs, histological details and presence of myositis-specific (MSA) or myositis-associated (MAA) antibodies. Among patients with IIM, a significantly greater proportion had systemic sclerosis 32/648 (4.9%) than mixed connective tissue disease (12/648, p = 0.003), primary Sjogren's syndrome (12/648, p = 0.003), systemic lupus erythematosus (10/648, p < 0.001) or rheumatoid arthritis (6/648, p = 0.0001). Polymyositis was the most common IIM diagnosis regardless of the presence or absence of CTD. MSA/MAA was more commonly detected in those with systemic sclerosis than those with IIM alone (OR 5.35, p < 0.005). The higher prevalence of SSc (compared with other CTDs) in IIM, together with the more frequent detection of autoantibodies in this group, suggests that these conditions may be linked.

Long-term follow-up of 62 patients with myositis

The aim of this work is to evaluate disease-related mortality and the course of the disease including functional outcome and quality of life. We did a follow-up study on a large prospective cohort of 62 patients with subacute-onset idiopathic inflammatory myopathy (IIM) (dermatomyositis (n = 24), nonspecific myositis (n = 34), necrotizing autoimmune myopathy (n = 4)) after treatment with corticosteroids only (randomized controlled trial comparing daily high-dosage prednisone with pulse therapy of dexamethasone). Development of connective tissue disease (CTD) or malignancy, disease course and mortality, functional outcome and quality of life were evaluated. After a mean follow-up of 3 years (SD 1.5), 22 % had developed a CTD and 17 % a malignancy. Disease-related mortality was 15 %. A monophasic disease course was found in 27 %. Most patients had a chronic (35 %) or polyphasic disease (35 %) course and experienced single or multiple relapses. Sixteen patients (33 %) were off medication after a mean of 1 year of treatment. Disability scores improved particularly in the first 18 months. At follow-up, 68 % still perceived disabilities. Quality of life scores as measured by the short-form (SF)-36 improved in the first 18 months. After 18 months, scores remained stable during the next years of follow-up and remained low compared to a normal population. (1) Two-thirds of the patients with an IIM have a polyphasic or chronic disease course and need maintenance treatment. (2) The impact on functional outcome and quality of life is considerable and does not improve further after 18 months.

Clinical and laboratory features of overlap syndromes of idiopathic inflammatory myopathies associated with systemic lupus erythematosus, systemic sclerosis, or rheumatoid arthritis

Because overlap syndromes (OSs) are rarely described, we analyzed retrospectively their frequencies and correlations in Brazilian series of 31 patients with dermatomyositis (DM)/polymyositis (PM) associated with systemic lupus erythematosus (SLE), systemic sclerosis (SSc), or rheumatoid arthritis (RA) attended at a referral single center. Myositis-specific autoantibodies (MSAs: anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, anti-SRP, anti-Mi-2) and myositis-associated autoantibodies (MAAs: anti-PM-Scl75, anti-PM-Scl100, anti-Ku) as well as specific autoantibodies related to SLE, SSc, and RA were investigated. The mean age of the OS patients (9 DM and 22 PM) was 44.6 ± 15.4 years, with a predominance of women (83.9 %) and white ethnicity (58.1 %). PM was the most frequent inflammatory myopathy, and the clinical presentation of DM/PM was significantly different among the OS groups. Overlap was found with SSc (48.4 %), SLE (29.0 %), and RA (22.6 %). The clinical manifestations of DM/PM were identified simultaneously with SSc and RA in the majority of cases, in contrast to identification in the SLE group (p < 0.05). All patients were positive for antinuclear antibodies, and the prevalence of MSA and MAA was 38.8 % in all OS groups, mutually exclusive, and more frequent in the SSc group. Comparing the clinical and laboratory features, there was a higher frequency of vascular (skin ulcers, Raynaud's phenomenon) and pulmonary (interstitial lung disease) involvement in the SSc group (p < 0.05). Moreover, there were no differences among the groups in relation to disease relapse and deaths. Concluding, this is the first study to show the different characteristics of a series of patients with connective tissue disease (CTD)-OS in the heterogeneous Brazilian population.

Association between a C8orf13-BLK polymorphism and polymyositis/dermatomyositis in the Japanese population: an additive effect with STAT4 on disease susceptibility

Background

Accumulating evidence has shown that several non-HLA genes are involved in the susceptibility to polymyositis/dermatomyositis. This study aimed to investigate the involvement of C8orf13–BLK, one of the strongest candidate genes for autoimmune diseases, in susceptibility to polymyositis/dermatomyositis in the Japanese population. A possible gene–gene interaction between C8orf13–BLK and STAT4, which we recently showed to be associated with Japanese polymyositis/dermatomyositis, was also analyzed.

Methods

A single-nucleotide polymorphism in C8orf13–BLK (dbSNP ID: rs13277113) was investigated in the Japanese population using a TaqMan assay in 283 polymyositis patients, 194 dermatomyositis patients, and 656 control subjects.

Results

The C8orf13–BLK rs13277113A allele was associated with overall polymyositis/dermatomyositis (P<0.001, odds ratio [OR] 1.44, 95% confidence interval [CI] 1.19–1.73), as well as polymyositis (P = 0.011, OR 1.32, 95% CI 1.06–1.64) and dermatomyositis (P<0.001, OR 1.64, 95% CI 1.26–2.12). No association was observed between the C8orf13–BLK rs13277113A allele and either interstitial lung disease or anti-Jo-1 antibody positivity. The C8orf13–BLK rs13277113 A and STAT4 rs7574865 T alleles had an additive effect on polymyositis/dermatomyositis susceptibility. The strongest association was observed in dermatomyositis, with an OR of 3.07 (95% CI; 1.57–6.02) for the carriers of four risk alleles at the two SNP sites, namely, rs1327713 and rs7574865.

Conclusions

This study established C8orf13–BLK as a new genetic susceptibility factor for polymyositis/dermatomyositis. Both C8orf13–BLK and STAT4 exert additive effects on disease susceptibility. These observations suggested that C8orf13–BLK, in combination with STAT4, plays a pivotal role in creating genetic susceptibility to polymyositis/dermatomyositis in Japanese individuals.

Acquired immune and inflammatory myopathies: pathologic classification

PURPOSE OF REVIEW

We discuss pathology-based characterization and classification of acquired immune and inflammatory myopathies (IIMs).

RECENT FINDINGS

Several types of IIMs do not fit well into the typical IIM subclassifications: dermatomyositis, polymyositis and inclusion body myositis (IBM). Myopathologic features that can provide additional diagnostic clarification in IIM are types of muscle fiber pathology; immune changes (cellular and humoral); and tissues with distinctive involvement (connective tissue, vessels and muscle fibers). Pathologic classification categories include immune myopathies with perimysial pathology (IMPP), a group that can be associated with antisynthetase antibodies; myovasculopathies, including childhood dermatomyositis; immune polymyopathies, active myopathies with little inflammation such as the myopathy with signal recognition particle antibodies; immune myopathies with endomysial pathology (IM-EP), illustrated by brachio-cervical inflammatory myopathy (BCIM); histiocytic inflammatory myopathies, like sarcoid myopathy; and inflammatory myopathies with vacuoles, aggregates and mitochondrial pathology (IM-VAMP), which have inclusion body myositis as a pathologic subtype and are poorly treatable. Some myopathologic features, like B-cell foci and alkaline phosphatase staining of capillaries or perimysium, are more likely to be present in treatable categories of IIM.

SUMMARY

Myopathology can be used to classify IIM. Identification of distinctive myopathologic changes in IIM can improve diagnostic and prognostic accuracy and focus treatment, therapeutic trials and studies of pathogenic factors.