Background Polymyositis (PM) and dermatomyositis (DM) have proximal muscle weakness. Reduced grip force has previously been shown in a cross sectional study.
Objectives To (I) compare women and men with PM/DM to reference values from the literature regarding grip force and Health Related Quality of Life (HRQoL) from time of diagnosis to 6 years of disease duration, (II) investigate how grip force changes over time and (III) investigate correlations between grip force and HRQoL.
Methods 89 patients with PM/DM (women n=52, men n=37) from the Swedish Myositis Network registry were included in this multicentre prospective study. Grippit was used to assess grip force and Short Form-36 (SF-36) for HRQoL.
Results (I) Women and men had reduced grip force compared to reference values at time of diagnosis (p<0.001) and up to 6 (p≤0.018) and 3 (p≤0.044) years disease duration respectively. Women and men rated lower HRQoL than reference values at time of diagnosis (p≤0.018).
(II) Over time there was an increase in grip force between time of diagnosis and to follow up at 1 year (p<0.001) and two years (p≤0.035). (III) There were moderate to high correlations between grip force and HRQoL
Conclusions Conclusions: Women and men with PM/DM had reduced grip force compared to reference values at time of diagnosis. The grip force improved after time of diagnosis and men reached normal levels at four years whereas women had low grip force even after 6 years. The correlation with HRQoL may indicate a clinical significance of the low grip force in these patients.
Disclosure of Interest None Declared