Risks for Developing ME/CFS in College Students Following Infectious Mononucleosis: A Prospective Cohort Study, 2020, Jason et al

[EndME]

I'm not sure if I've understood your question.

The group is selected based on those meeting the category at 6 months, e.g. S-ME/CFS at 6 months. The scores at baseline and IM (the single measurement point within 6 weeks of symptom onset) are the scores at those timepoints for those that end up in the 6-month category. So things works backwards from the selection at 6 months.

Let me know if this isn't what you asked

Hi Simon, I got that part. Maybe I misunderstood the study, but I was wandering if similar data existed for the groups that are being classified by diagnostic criteria without working backwards 6 months after IM infection. For example I was wandering how many people in the whole student population (including those that never developed IM) would be in the S-ME/CFS group at time 1 to get a feel for how this matches other prevalence estimates and I thought something similar for the ME/CFS group would be interesting to get a hunch at how often Fukuda might be diagnosing problems not necessarily related to IM or ME/CFS. Does that data exist?

 

[Simon M]

What's the true rate of ME/CFS post IM? (2)

The three other studies I mentioned earlier all have ME/CFS post-IM rates of about 12%. But looking more carefully, they also support higher rates.

1. Katz, 2009 ME/CFS post mono in adolescents
Published rate 13%, corrected rate 17%, Canadian criteria (probably).

13% is an uncorrected figure that does not adjust for losses:.

The study diagnosed 39 cases out of 301 people they tried to contact. However, they were only able to contact 286 (95%) and of the 70 people (24%) of people who did not recover fully, 53 (76% of these) were clinically assessed. 39 of those assessed (74%) were diagnosed with ME/CFS. Correcting for losses, 39/(286x 76%)= 17% of IM cases resulted in ME/CFS at 6 months.

Criteria and thresholds for fatigue and function
"We used the Jason et al. (15) revision (PDF) of the Fukuda (1) criteria to diagnose CFS." Looking at this reference, it appears to be a paediatric implementation of the Canadian criteria, with mandatory components, unlike Fukuda.

Fatigue is assessed by a 7 item frequency and 7 item severity scale, requiring a score of at least 4 on both. Every study seems to have its own approach to assessing fatigue. This seems reasonable. I'm not sure how function is assessed, but there doesn't seem to be a specific scale for consistency.

Overall, the 17% seems reasonable. If these are Canadian criteria (views?), then this 17% would be comparable with the 8% for S-CFS, since almost all ME/CFS cases are Fukuda only. On the other hand, the 23% for the Jason study is significantly higher, and the posts above suggest it includes non-ME/CFS cases. Things look a bit muddy or inconsisent to me.

Comments on Dubbo & Pedersen studies to follow (spoiler: I'm not sure we have any figures we can truly trust).

 

[Simon M]

Hi Simon, I got that part. Maybe I misunderstood the study, but I was wandering if similar data existed for the groups that are being classified by diagnostic criteria without working backwards 6 months after IM infection. For example I was wandering how many people in the whole student population (including those that never developed IM) would be in the S-ME/CFS group at time 1 to get a feel for how this matches other prevalence estimates and I thought something similar for the ME/CFS group would be interesting to get a hunch at how often Fukuda might be diagnosing problems not necessarily related to IM or ME/CFS. Does that data exist?

No. Diagnosis involves clinical examination, and was only done for those who didn't recover from IM. But it is an interesting point.

The prevalence of ME/CFS of people under 20 (almost all in this stiudy) is probably aboiut 0.3%, and I doubt many of those are able to attend university. I would be very interested to know how many of the S-ME/CFS group would have qualified for it at baseline, givem that about half had moderate fatigue then, and their symptom rate was high (marginally higher than the ME/CFS group at 6 months (21.2 vs 19.6).

 

[EndME]

No. Diagnosis involves clinical examination, and was only done for those who didn't recover from IM. But it is an interesting point.

The prevalence of ME/CFS of people under 20 (almost all in this stiudy) is probably aboiut 0.3%, and I doubt many of those are able to attend university. I would be very interested to know how many of the S-ME/CFS group would have qualified for it at baseline, givem that about half had moderate fatigue then, and their symptom rate was high (marginally higher than the ME/CFS group at 6 months (21.2 vs 19.6).

Thanks!