Validation of the multiple sclerosis international quality of life (MusiQoL) questionnaire in Norwegian patients.

OBJECTIVES

To assess the validity and reliability of the multidimensional, self-administered Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire, previously validated in a large international sample, in Norwegian patients.

PATIENTS AND METHODS

Patients with different types and severities of multiple sclerosis (MS) were recruited from a single MS centre in Norway. All patients completed the MusiQoL and Short Form-36 (SF-36) QoL questionnaires at baseline and a mean of 21 (SD 7) days later. A neurologist collected sociodemographic, MS history and outcome data. Construct validity, internal consistency, reproducibility and external consistency were tested.

RESULTS

One hundred and four patients were evaluated. Construct validity was confirmed in terms of satisfactory item internal consistency correlations in eight of nine MusiQoL dimensions (Spearman's correlation: 0.34-0.79) and scaling success of item discriminant validity (75.0-100%). All dimensions of the MusiQoL questionnaire exhibited satisfactory internal consistency (Cronbach's alpha: 0.44-0.87) and reproducibility (intraclass correlation coefficients: 0.36-0.86). External validity testing showed that the global MusiQoL score correlated significantly with all but one individual SF-36 dimension score (Spearman's correlation: 0.29-0.56).

CONCLUSIONS

These results demonstrate that the Norwegian-language version of the MusiQoL questionnaire is a valid and reliable instrument for assessing health-related QoL in Norwegian patients with MS.