Overlap myositis, a distinct entity beyond primary inflammatory myositis: A retrospective analysis of a large cohort from the REMICAM registry.

Inflammatory idiopathic myositis (IIM) comprises a heterogeneous group of systemic muscular diseases that can occur together with other connective tissue diseases (CTD), named overlap myositis (OM). The question of whether OM is a distinct entity still remains controversial. The present study was conducted to assess the clinical and prognostic differences between patients diagnosed with OM, primary polymyositis (PM) and primary dermatomyositis (DM). The study consists of a retrospective longitudinal and multicenter series of IIM patients. Patients were classified as OM, PM and DM. Overlap myositis was defined as patients fulfilling criteria for IIM plus criteria for other CTD (namely systemic sclerosis, systemic lupus erythematosus, mixed connective tissue disease, rheumatoid arthritis and primary Sjögren's syndrome). A total of 342 patients were included (98 OM, 137 PM and 107 DM). Overlap myositis patients, in comparison with PM and DM, showed significant differences, with more extramuscular involvement, particularly more arthritis (66%, 34.6% and 48.1%, respectively), puffy fingers (49.5%, 11.1% and 24.3%), sclerodactyly (45.4%, 2.2% and 2%), dysphagia (41.8%, 18.2% and 26.4%), Raynaud phenomenon (65.3%, 16.9% and 19.8%), leucopenia (28.9%, 2.2% and 8.4%), thrombocytopenia (8.2%, 2.2% and 1.9%), interstitial lung disease (ILD) (48%, 35% and 30.8%), renal manifestations (13.4%, 3.7% and 1.9%), and more severe infections (41.3%, 26.7% and 21%). No significant differences were found in survival between groups in log rank test (P = 0.106). Multivariate adjusted survival analyses revealed a worse prognosis for severe infections, ILD and baseline elevation of acute phase reactants. Overlap myositis stands out as a distinct entity as compared to PM and DM, featuring more extramuscular involvement and more severe infections. Close monitoring is recommended in this subset for early detection and treatment of possible complications.

Nuño-Nuño L ，Joven BE ，Carreira PE ，Maldonado-Romero V ，Larena-Grijalba C ，Llorente Cubas I ，Tomero E ，Barbadillo-Mateos MC ，García de la Peña Lefebvre P ，Ruiz-Gutiérrez L ，López-Robledillo JC ，Moruno-Cruz H ，Pérez A ，Cobo-Ibáñez T ，Almodóvar R ，Lojo L ，García de Yébenes MJ ，López-Longo FJ ... -  《-》

Novel classification of idiopathic inflammatory myopathies based on overlap syndrome features and autoantibodies: analysis of 100 French Canadian patients.

Troyanov Y ，Targoff IN ，Tremblay JL ，Goulet JR ，Raymond Y ，Senécal JL ... -  《medicine》

The spectrum of idiopathic inflammatory myopathies in South Africa.

Chinniah KJ ，Mody GM 《-》

Polymyositis: is there anything left? A retrospective diagnostic review from a tertiary myositis centre.

The current classification criteria for idiopathic inflammatory myopathy (IIM) retain PM as a major disease subgroup. However, evolution in the understanding of IIM has suggested that many of these patients could be better described as having an alternative diagnosis. In the present study, we apply the latest understanding of IIM subtyping to retrospectively review PM diagnoses in a large cohort of IIM patients. Within a previously reported cohort of 255 patients from a UK tertiary myositis clinic, 37 patients classified as PM according to both the EULAR/ACR IIM criteria and expert opinion were identified. Clinical data and complementary tests were reviewed, and consensus decisions regarding final classification were reached in each case. Nine (9/37, 24.3%) patients remained classified as PM, 3.5% (9/255) of the original cohort; these PM patients were seronegative for myositis antibodies, responsive to immunosuppression, and in 4/7 (57.1%) patients where muscle biopsy was performed had HLA-1 upregulation and endomysial inflammatory infiltrates. Immune-mediated necrotizing myopathy (5/37, 13.5%) and connective tissue disease overlap myositis (7/37, 19%) were the main alternative diagnoses. The remaining patients were diagnosed as: unspecified myopathy (6/37, 16%), dermatomyositis (2/37, 5%), cancer-associated myopathy (3/37, 8.1%), and non-inflammatory myopathy (1/37, 3%, myofibrillar myopathy). Four patients (4/37, 10%) had insufficient data available to confidently reclassify. Our study confirms that PM can now be considered a rare IIM subgroup. A thorough examination, complete myositis autoantibody panel, and careful interpretation of the biopsy results is recommended to confirm the correct IIM sub-type.

Loarce-Martos J ，Lilleker JB ，Parker M ，McHugh N ，Chinoy H ... -  《-》

Long-term pulmonary outcomes and mortality in idiopathic inflammatory myopathies associated with interstitial lung disease.

Cobo-Ibáñez T ，López-Longo FJ ，Joven B ，Carreira PE ，Muñoz-Fernández S ，Maldonado-Romero V ，Larena-Grijalba C ，Cubas IL ，Muriel ET ，Mateos CB ，de la Peña Lefebvre PG ，Gomez-Gomez A ，Nogal LB ，Pérez A ，Almodovar R ，Lojo L ，Ruiz-Gutiérrez L ，López-Robledillo JC ，García de Yébenes MJ ，Nuño-Nuño L ... -  《-》