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Acta Reumatológica Portuguesa
Original article
Original article
Predictors of myositis in mixed connective tissue disease: A multicentre retrospective study
Abstract
Objectives: We aimed to identify clinical and serological predictors of myositis in mixed connective tissue disease (MCTD).
Methods: We performed a nationwide, retrospective, multicentre study including adult-onset MCTD patients fulfilling at least one of the following diagnostic criteria: Sharp’s, Kasukawa, Alarcón-Segovia, or Kahn’s. Univariate analysis was performed using Chi-square, Fisher exact, Student’s t or Mann-Whitney U tests, as appropriate. Multivariate analysis was performed using binary logistic regression.
Results: Ninety-eight patients were included. Myositis was observed in 43.9% of patients, of whom 60.5% had myositis at disease onset.
Proximal muscle weakness was described in 30 patients with muscle involvement (70%). Gastrointestinal involvement was identified in 28% and respiratory involvement in 29% of myositis patients. In the same subgroup of patients, 41.7% had a myopathic pattern on electromyography, and 47.1% had histological myositis features in the muscle biopsy.
Fever (OR=6.96, p=0.022) was an independent predictor of myositis, regardless of sex, age at diagnosis, ancestry, and respiratory involvement. African ancestry (OR=8.39, p=0.019), leukopenia at the disease onset (OR 6.24, p=0.021), and younger age at diagnosis (OR=1.07/year, p=0.035) were identified as independent predictors of myositis at disease onset, regardless of sex and scleroderma pattern in capillaroscopy.
Conclusions: Myositis is a common manifestation of MCTD, even at the disease onset. African ancestry, leukopenia at the disease onset, younger age at diagnosis, and fever should prompt a thorough evaluation for myositis.
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Publication:
2024-06-28
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Ana Melo, Manuel Silvério-António, Joana Martins-Martinho, Francisca Guimarães, Eduardo Dourado, Daniela Oliveira, Jorge Lopes, André Saraiva, Ana Gago, Margarida Correia, Ana Fernandes, Sara Dinis, Rafaela Teixeira, Susana Silva, Carlos Costa, Tiago Beirão, Carolina Furtado, Pedro Abreu, Nikita Khmelinskii. Predictors of myositis in mixed connective tissue disease: A multicentre retrospective study. ARP Rheumatology, Vol 3, nº3 2024:174-181
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