SOME DISEASES OF MUSCLE

A bibliometric analysis of idiopathic inflammatory myopathies from 1982 to 2021

OBJECTIVE

There has been an increasing number of literature related to idiopathic inflammatory myopathies (IIM) in the past few decades. However, there is a lack of intuitive and systematic analysis of research on IIM. Therefore, this study aimed to perform a bibliometric analysis to identify the current trends and hotspots of research on IIM.

METHODS

Articles and reviews on IIM published during 1982-2021 were acquired from the Web of Science Core Collection (WoSCC) database. VOSviewer application was applied to conduct a network analysis of the keywords, institutions, and countries. The top 100 most-cited publications regarding IIM were analyzed.

RESULTS

In total, 665 publications were included. Globally, the USA produced the most articles on IIM (144). Karolinska Institutet was the institution with the most outputs (47). Rheumatology ranked on top of journals, with 47 IIM-related documents collecting a total of 1420 citations. In the area of IIM documents, biomarkers were the most common research theme. According to the co-occurrence analysis of keywords, "cardiac involvement," "criteria," and "refractory adult" were identified as significant future research centers.

CONCLUSION

The scientific literature on IIM has advanced rapidly in the past 4 decades. The classification criteria, treatment, and extramuscular manifestations of IIM have been identified as promising research frontiers in the field. The global status and trends of the IIM literature from a bibliometric aspect can offer a helpful guidance and new insight for researchers and medical workers in the domain. Key Points • This study reveals the topic trends and knowledge structure of idiopathic inflammatory myopathies literature over the last 40 years. • This study identifies potential future research hotspots, including "cardiac involvement," "criteria," and "refractory adult."

Idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM), also known as myositis, are a heterogeneous group of autoimmune disorders with varying clinical manifestations, treatment responses and prognoses. Muscle weakness is usually the classical clinical manifestation but other organs can be affected, including the skin, joints, lungs, heart and gastrointestinal tract, and they can even result in the predominant manifestations, supporting that IIM are systemic inflammatory disorders. Different myositis-specific auto-antibodies have been identified and, on the basis of clinical, histopathological and serological features, IIM can be classified into several subgroups - dermatomyositis (including amyopathic dermatomyositis), antisynthetase syndrome, immune-mediated necrotizing myopathy, inclusion body myositis, polymyositis and overlap myositis. The prognoses, treatment responses and organ manifestations vary among these groups, implicating different pathophysiological mechanisms in each subtype. A deeper understanding of the molecular pathways underlying the pathogenesis and identifying the auto-antigens of the immune reactions in these subgroups is crucial to improving outcomes. New, more homogeneous subgroups defined by auto-antibodies may help define disease mechanisms and will also be important in future clinical trials for the development of targeted therapies and in identifying biomarkers to guide treatment decisions for the individual patient.

Polymyositis: does it really exist as a distinct clinical subset?

PURPOSE OF REVIEW

To summarize information on polymyositis; diagnosis, definitions, published data and opinions.

RECENT FINDINGS

Polymyositis originally referred to inflammatory muscle diseases presenting with muscle weakness and inflammatory cell infiltrates on muscle tissue visible by microscopy. Over time and with improved technology to immunophenotype infiltrating inflammatory cells and characterize muscle fibres, the meaning of polymyositis changed and became more specific. There is ongoing controversy over the term polymyositis, with proponents for a strict definition based on histopathological and immunohistochemical features on muscle biopsies whereas others advocate for a broader clinical and histopathological phenotype. Over the past decades, the discovery of several myositis-specific autoantibodies together with distinct histopathological features have enabled the identification of new subsets previously labelled as polymyositis notably the antisynthetase syndrome and the immune-mediated necrotizing myopathies thus reducing the number of patients classified as polymyositis.

SUMMARY

There are still a small number of patients among the idiopathic inflammatory myopathies that can be classified as polymyositis as discussed in this review but the entity is now considered relatively rare.

Incidence of serious complications of corticosteroid therapy in respiratory disease. A retrospective survey of patients in the Brompton hospital

A retrospectively controlled study is described of mortality and serious morbidity in 550 patients treated with corticosteroids and 499 controls. The overall incidence of side-effects was similar in both groups, but gastro-intestinal bleeding, diabetes, and mental disturbance early in treatment occurred more frequently in the corticosteroid group. Other individual side-effects did not occur significantly more often than in the controls, but there was an overall increased frequency of complications with increased dose, and also an increased mortality with increase in the maintenance dose. Gastro-intestinal bleeding was not related to a past or present chronic peptic ulcer, and was not commoner in treated patients. Reactivation of tuberculosis and exacerbation of mental disturbance did not occur. Weight gain occurred in 29% of patients, but appeared to be related closely to a satisfactory response to treatment. Hypertension occurred in 4% of the treated group. Overall mortality in the two groups was similar. Mortality due specifically to corticosteroids was difficult to assess: two patients died of haematemesis and three died with severe asthma during withdrawal of treatment, but there was no increase in mortality following physical stress in the treated series. Sudden death in asthmatics was not more frequent in corticosteroid-treated patients. All seven control patients who died suddenly with asthma were middleaged. Increase in duration of treatment was not associated with increased risk. Indeed the long-term, low-dose group had a lower incidence of complications than the rest and a mortality similar to that of the controls. A trial of corticosteroids for less than one month carried no risk in 41 patients.