Background: The existing health-related quality of life questionnaires on multiple sclerosis (MS) only partially reflect the patient's point of view on the reduction of activities of daily living. Their development and validation was not performed in different languages. That is what prompted the development of the Multiple Sclerosis International Quality of Life (MusiQoL) Questionnaire as an international multidimensional measurement instrument. This paper presents this new development and the results of the German subgroup versus the total international sample.
Patients and methods: A total of 1,992 MS patients from 15 countries, including 209 German patients, took part in the study between January 2004 and February 2005. The patients took the MusiQoL survey at baseline and at 21±7 days as well as completing a symptom-related checklist and the SF-36 short form survey. Demographics, history and MS classification data were also generated. Reproducibility, sensitivity, convergent and discriminant validity were analysed.
Results: Convergent and discriminant validity and reproducibility were satisfactory for all dimensions of the MusiQoL. The dimensional scores correlated moderately but significantly with the SF-36 scores, but showed a discriminant validity in terms of gender, socioeconomic status and health status that was more pronounced in the overall population than in the German subpopulation. The highest correlations were observed between the MusiQoL dimension of activities of daily living and the Expanded Disability Status Scale (EDSS).
Conclusion: The results of this study confirm the validity and reliability of MusiQoL as an instrument for measuring the quality of life of German and international MS patients.