A sample size of 00 patients (00 per arm) achieves 00% power to detect a difference of 00 (standard deviation 00) in the MSQOL-00 MHC in a design with three repeated measurements, assuming an intra-subject correlation between observations of 0.00, an alpha error of 0.00, and 00% of the patients lost to follow-up ([S0 Appendix](#pone.0000000.s000){ref-type="supplementary-material"}). Because no data on the READY for MS were available when the study was designed, our estimate was based on the large effect size for 