Background The Myositis Activity Profile (MAP), a questionnaire to assess limitations of activities of daily life in patients with inflammatory myopathy (IM), was developed and tested on psychometric properties in Sweden and later on translated and validated in English1,2. To the best of our knowledge, there is no validated version available for German speaking patients.
Objectives To translate and cross-culturally adapt the MAP into German language and to determine content and construct validity.
Methods A cross-cultural adaptation of the English version of the MAP into German was performed following international guidelines. To assess content validity of the new German version, patients rated difficulty and importance of items of the MAP using a visual analog scale (VAS range 0–10). For construct validity the correlation between the MAP and five functional tests (Short Physical Performance Battery, one leg stand, Grip Ability Test, upper and lower Progressive Isoinertial Lifting, and the 6 minute walk) were analyzed with the Spearman correlation coefficient. Additionally, for discriminative validity differences between patients and age and gender matched healthy controls were analyzed using the Mann-Whitney- U Test. Item fit within subscales was calculated by Cronbach's alpha.
Results Twenty German speaking patients with a diagnosis of acute (20%), subacute (25%) or chronic (55%) myositis were included. Participants were 56.5 ±10.13 years old and 75% of them were female. The median combined difficulty and importance of the 32 items of the MAP was 5.67 (range 5.3–6.5). Correlations between the total score of the MAP and the Short Physical Performance Battery (-0.52), Grip Ability Test (0.52), Progressive Isoinertial Lifting Evaluation (lumbal part: -0.62, cervical part -0.60) and the 6 minute walk test (-0.69) were moderate and the correlation with the one leg stand test was low (-0.26). Healthy participants had significant lower scores (single items, subscales and total score) than patients (p≤0.05). Cronbach's alpha coefficients for the four subscales varied between 0.85 and 0.92.
Conclusions This initial validation of the German version of the MAP showed that the 32 items from the English version were also suitable for Swiss conditions. Cronbach's alpha coefficients were similar to those from the English version. As expected the MAP correlated moderately with functional tests, except with the one leg stand. Although balance may be important in patients with IM, the MAP does not cover balance ability. In summary, the MAP seems to be a valid and easy applicable methodology for assessing limitations of activity in daily life. However, further research is required to confirm these preliminary results and to test reliability.
Alexanderson H, Lundberg IE, Stenstrom CH: Development of the myositis activities profile–validity and reliability of a self-administered questionnaire to assess activity limitations in patients with polymyositis/dermatomyositis. J Rheumatol 2002
Alexanderson H, Reed AM, Ytterberg SR: The Myositis Activities Profile-initial validation for assessment of polymyositis/dermatomyositis in the USA. J Rheumatol 2012
Disclosure of Interest None declared