Trial design
fatigue
We conducted an observer-blinded non-inferiority multicentre randomized clinical trial (RCT), with patients being allocated to face-to-face or blended CBT. In all treatment sites, therapists delivered both CBT formats.The non-inferiority margin was based on the results of the TREFAMS-CBT study that tested the effectiveness of CBT compared to MS nurse consultations. The between-group difference for fatigue was 6.67 points (95% confidence interval (CI): 2.70–10.68) on the Checklist Individual Strength (CIS) fatigue severity subscale.The study was approved by the Medical Ethical Review Committee, Amsterdam University Medical Centres (registration 2017.538, NL62622.029.17), and by the local ethical committees of participating hospitals and rehabilitation centres. The study was registered in the Dutch Trial Register (NTR6966; registered 18 January 2018 