Clinical and laboratory features of scleroderma patients developing skeletal myopathy

Skeletal muscle involvement, or myopathy, has been a recognized feature of systemic sclerosis (SSc). We studied retrospectively 302 Japanese patients with SSc to elucidate the clinical and laboratory features in scleroderma patients developing skeletal myopathy during their clinical course. Forty-three patients (14%) developed skeletal myopathy during their course of the disease. The mean age of the patients who developed skeletal myopathy was significantly lower than that of those who did not. The ratio of male to female was significantly higher in the myopathic patients. The patients with diffuse cutaneous SSc were more likely to develop myopathy than those with limited cutaneous SSc. The prevalences of heart involvement, pulmonary fibrosis, diffuse pigmentation of the skin, and contracture of phalanges were significantly greater in those with skeletal myopathy than in those without. None of the patients with skeletal myopathy had anticentromere antibody. These findings suggested that the SSc patients with severe internal organ involvement, such as pulmonary fibrosis and heart disease, and some other complications were prone to develop skeletal myopathy during their clinical course of the disease.