Background Polymyositis (PM) and dermatomyositis (DM) are idiopathic inflammatory myopathies with muscle weakness and reduced muscle endurance. The impairments lead to activity limitation, participation restriction and reduced quality of life.
Objectives To investigate how grip force, activity limitation and quality of life change longitudinally from disease onset and up to five years forward. To investigate differences between women and men in regards to these variables over time and compare to reference values.
Methods A prospective longitudinal cohort study. Patients with myositis are annually registered in the Swedish Myositis Network registry. Patients with PM/DM who had measures on impairment (grip force (Grippit)), activity limitation (Myositis activities Profile (MAP)) or quality of life (Short-Form-36 (SF-36)) were included. The cohort was followed up to 5 years from disease onset.
Results The cohort consisted of 63 patients with PM and DM (women n=39, men n=24). Both women and men with PM/DM had reduced grip force compared to gender and age matched reference values, women up to four years and men up to three years after disease onset. The result also showed that men with PM/DM increased their grip force in both hands, while women did not change significantly from disease onset and up to five years.
In MAP subscales movement, avoid over exertion, work/school work and leisure, men had less activity limitation than women. Activity limitation measured by MAP decreased in men with PM/DM up to two years from disease onset in activities regarding movement, social activities, work/school work and leisure. Women remained unchanged over time in all subscales regarding activity limitation measured by MAP.
Women with PM/DM rated less than men in quality of life dimensions (SF-36) role physical, bodily pain, general health, vitality and mental health. Men with PM/DM increased the scoring in quality of life dimensions physical functioning and mental health over time. In women there were no detectable changes over time in any dimensions on quality of life measured by SF-36. Compared to reference values, quality of life for women was reduced in the SF-36 dimensions role physical up to five years, physical functioning up to two years and bodily pain, general health and vitality up to one year after disease onset. Men had only lower values than reference values at disease onset in SF-36 dimensions general health and mental health.
Conclusions Even though the disease activity decreased over time, patients with PM/DM still perceived activity limitation, impaired grip force and restricted quality of life. Especially women had impaired grip force and restricted quality of life compared to reference values. Activity limitation decreased over time for men while it remained unchanged for women.
Thus women with PM/DM perceive more disability than men concerning grip force, activity limitation and quality of life.
Disclosure of Interest None Declared