Study findings challenge the content validity of the Canadian Consensus Criteria for adolescent CFS

[Dolphin]

3958 steps per day seems very high for a group of ME patients.

There is a lot of variation in the severity of people with ME, from those who can work or study full-time (likely with difficulty or some sacrifices) right down to those bedbound. And bedbound and a percentage of other severely affected patients tend to not to be in outpatient studies.

 

[Dolphin]

One difference between the groups that isn't mentioned in the abstract is step count

Steps per day - number, mean (SD)

Canadian Clinical Criteria group 3958 (2142)

Non-Canadian Clinical Criteria group 5144 (2482)

p value=0.006

Note that the difference didn't hold up at 30 weeks:

At week 30, neither steps per day nor fatigue score were significantly different among the two groups when adjusted for baseline values and allocation to clonidine/placebo (p=0.649 and p=0.831, respectively).

However, that's not quite the same thing though as by 30 weeks, different people could be in different groups.

However, it could have a relevance in the following way:

Furthermore, the prognosis over a 30 week observational period was equal. Thus, the Canadian Consensus Criteria seems to have poor content validity, questioning its usefulness in research as well as in clinical practice.

Though if the same (different) levels were recorded at both times, one would get a p=1 I think when adjusted for baseline but there would still be a difference between the groups.

 

[Hip]

If you look at this list of some of the ME/CFS enterovirus studies performed over the decades, even the studies performed in the 1980s and 1990s — which could not have used the CCC, because the CCC came out in 2003 — found major differences in the presence of enteroviruses between the ME/CFS patients and healthy controls.

These differences between patients and controls were just as significant as those found by Dr Chia in the mid 2000s, using the CCC.

This possibly suggests that the precise ME/CFS criteria used in studies may not be that important.



It would have been interesting if this present study had tested for enteroviral infections, and compared the two groups for the prevalence of these infections.