RESUMEN
BACKGROUND: Multiple sclerosis (MS) has a profound impact on patients' health-related quality of life (HRQoL). It is unclear how HRQoL can be best assessed for different purposes. This study aimed to compare two HRQoL questionnaires of differing lengths for feasibility of administration, patient perceptions and psychometric properties. METHODS: This was an open-label, 24-month study in 334 patients with relapsing MS treated with subcutaneous interferon ß-1a. At baseline and months 6, 12, 18 and 24, patients completed the Multiple Sclerosis International Quality of Life (MusiQoL) and Multiple Sclerosis Quality of Life-54 (MSQOL-54) questionnaires and compared them using an evaluation questionnaire. HRQoL scores over time and psychometric properties (correlations with clinical disease measures, relative validity and responsiveness to change) of the questionnaires were assessed. RESULTS: A minority of patients had missing items on either HRQoL measure. Completion time was significantly shorter for MusiQoL versus MSQOL-54 (p<0.0001). Patients felt that MusiQoL was easier to use than MSQOL-54 but preferred MSQOL-54 in terms of thoroughness. Mean HRQoL scores increased significantly from baseline to 24 months; correlations of both measures were stronger with an anxiety and depression measure than with disability or recent relapse occurrence. Relative validity and responsiveness to change were similar for both instruments. CONCLUSION: The shorter MusiQoL is suitable for evaluating HRQoL in patients with MS and may be more practical to administer than the more thorough MSQOL-54.