All patients with polymyositis hospitalized or seen in the rheumatology clinics at Louisiana State University Medical Center in Shreveport and two university-affiliated medical centers during the period of July 1987 to June 1988 were eligible for inclusion in the study. Subjects were identified by review of discharge diagnoses and clinic records at those institutions. The diagnosis of polymyositis was made by the established criteria of Bohan and Peters. Derma-tomyositis was diagnosed when the above criteria were satisfied and the characteristic heliotrope rash also was present. Patients were excluded if they had associated collagen vascular disease at the time of the study or if they were unable to exercise. asthma inhalers
The patients underwent an initial clinical evaluation by a rheumatologist (B.B., R. W.) to ascertain disease activity Clinical activity was defined as the presence of constitutional symptoms, muscle weakness and abnormal serum muscle enzyme values. Biochemical activity was defined as elevation of muscle enzyme levels in the absence of clinical examination findings. Patients without clinical or biochemical evidence of polymyositis were considered to have inactive disease. The disease duration was defined from date of onset of active disease to the time of the exercise study. Polymyositis was considered chronic if there was persistent disease activity despite appropriate medical therapy for at least one year.