Proposed study to compare FACIT-Fatigue and PROMIS Fatigue 10a individual item responses and scores over specific periods of follow-up. It would be useful, since it was not written explicitly, that the specific aims to examine floor/ceiling effects (distributions), internal consistency and convergent validity pre-specifiy which fatigue measure is focused on: FACIT-Fatigue or PROMIS Fatigue. Presumably, one is the “main endpoint” and the second is being used for the convergent validity aim. Or have I misunderstood?
Also, I was unclear why the authors pre-specified examination of the Crohn’s Disease Activity Index (CDAI), as the 2 trials requested are studies of patients with rheumatoid arthritis – I highly doubt the CDAI was collected. Perhaps this is a copy/paste error from another project?