Post

1) There's a new critical review of patient-reported outcome measures in ME/CFS and Long Covid. The paper argues that trials often fail to include important symptom domains such as post-exertional malaise, dysautonomia and mast cell activation symptoms.

2) Some of the authors are patients themselves. They reviewed 37 myalgic encephalomyelitis and 68 long COVID trials that focus on biomedical interventions and used 397 outcome measures in total. Most of the trials relied on patient-reported outcome measures (PROMs).

3) Several widely used PROMs such as the Beck Depression Inventory (BDI) or the Fatigue Severity Scale (FSS) provide no or limited published evidence for reliability validity, or responsiveness in patients with ME/CFS.

4) The Chalder Fatigue Scale is the only ME specific PROM that has been evaluated for content validity by cognitive interviewing (the current standard) and it performed very poorly. 5 items lacked clarity and it asks patients to rate their according to their life before illness.

5) Other issues in PROMS used in ME/CFS trials are lack of patient involvement in development, ceiling and/or floor effects where many patients score the the maximum/minimum, and failure to take successful pacing into account (as this reduces symptoms).

6) 54% of PROMs in LC or ME/CFS clinical trials mainly assess fatigue. In contrast, PROMs that specifically assess PEM are only used in 18% of LC and 5% of ME/CFS trials. Often the DSQ-PEM is used for PEM but it has multiple problems (e.g it doesn't consider symptom delay).

8) For mental health measures, it mentions the problem that commonly used measures often count physical symptoms as well. The PHQ-9 for instance explores tiredness, appetite and sleep problems and attributes these to depression and anxiety.

9) The paper also mentions that hardly any trials consider mast cell activation symptoms such as pruritus and flushing. For non PROM outcome measures it recommends to include return to work and actimetry and also to assess re-infection with Sars-Cov-2.

10) Link to the paper (open-access): van Rhijn-Brouwer et al. Outcome measures in long COVID clinical trials: a review.