Reliability and acceptability of the Multiple Sclerosis Quality of Life-29 questionnaire in an English-speaking cohort

Background: Multiple Sclerosis Quality-of-Life Questionnaire-54 (MSQoL-54) is a disease-specific instrument for assessing health-related quality of life (HRQoL). Due to the number of items, the time taken to complete it is long. A shorter 29-item version, Multiple Sclerosis Quality-of-Life Questionnaire-29 (MSQoL-29) is yet to be evaluated in English.

Objective: To assess reliability and acceptability of English version of MSQoL-29.

Methods: Among 100 participants with MS who first completed both MSQoL-54 and MSQoL-29, 91 completed MSQoL-29 after 4–8 weeks. We looked for internal consistency (Cronbach’s alpha), acceptability, reliability (intraclass correlation coefficients (ICCs)) and agreement (Bland–Altman plots).

Results: ICCs were strongly positive between MSQoL-54 and MSQoL-29 (Physical Health Composite (PHC) –ICC = 0.914, confidence interval (CI) = 0.872–0.942; Mental Health Composite (MHC) – ICC = 0.875, CI = 0.814–0.916) and between the two MSQoL-29 (PHC – ICC = 0.970, CI = 0.955–0.980; MHC – ICC = 0.937, CI = 0.904–0.958). On Bland–Altman plots, the MSQoL-29 scores of 95% of participants during two visits were within the limits of agreement (LOAs). Time taken to complete MSQoL-29 was 7.2 ± 2.9 minutes and MSQoL-54 was 19.79 ± 5.4 minutes (p = 0.0001).

Conclusion: MSQoL-29 has good test–retest reliability in English-speaking population and was quicker to complete.