CDC (2016): Methods of applying the 1994 case definition of chronic fatigue syndrome

[Scarecrow]

I think this could exclude some people with genuine ME/CFS.

How many of the participants might have been excluded on this criterion alone but were classified as CFS under M2?


This is a staggering statistic and might be explained by your observation:

From Table 5

Physical Functioning <=70
M1/M2 (n=44) 32 (72.73 %)
M1 (n=15) 3 (20.00 %)
M2 (n=27) 14 (51.85 %)

Only 20% of people classified as CFS under M1 had a score of 70 or less in physical functioning.

 

[Dolphin]

I'm not sure that this has much to do with severity. More to do with duration of illness, how you've adapted to it and, perhaps, stability of symptoms. If the question was posed in terms of "Compared to your pre-illness activity, have you had forgetfulness or memory [or concentration] problems that have caused you to cut back on activities?", it might prompt a different - and correct - response. Perhaps it's implicit in the question that it's in comparison to pre-illness but it would certainly have caught me out. And a question shouldn't be phrased in such a way that it requires this level of analysis.

Here's a sample from the PACE Trial on how a questionnaire was worded It was not explained to those filling in the questionnaires that they should compared to when they were last well, that would be a big problem.

We would like to know more about any problems you have had with feeling tired, weak or lacking in energy in the last month. Please answer ALL the questions by ticking the answer which applies to you most closely. If you have been feeling tired for a long while, then compare yourself to how you felt when you were last well. (Please tick only one box per line).

 

[Dolphin]

I think this could exclude some people with genuine ME/CFS.

How many of the participants might have been excluded on this criterion alone but were classified as CFS under M2?

Not sure why you are mentioning M2 specifically?

This is a staggering statistic and might be explained by your observation:

From Table 5

Physical Functioning <=70
M1/M2 (n=44) 32 (72.73 %)
M1 (n=15) 3 (20.00 %)
M2 (n=27) 14 (51.85 %)

Only 20% of people classified as CFS under M1 had a score of 70 or less in physical functioning.

Which observation?

 

[Kati]

Regarding the questionnaires, there needs to be a tick box that says we are too cognitively challenged to answer the questions, and that cognitive exertion is causing exacerbation of illness.

Biomarkers please!

 

[Scarecrow]

Not sure why you are mentioning M2 specifically?

If you are excluded under M1 for answering that fatigue is relieved by rest most or all of the time, you can still qualify under M2. A higher percentage of participants classified under M2 had a physical functioning score <=70.

Which observation?

That you could be excluded under M1 and still have ME/CFS.

 

[jimells]

What does this tell you about funding channels and ability to produce change?

Recently I read someplace that if the NIH had been chosen to research polio we would have the world's best iron lung - and no polio vaccine. This is why we need extramural funding from NIH instead of halfway-done intramural research. I don't really understand why, but these government agencies will never get the job done. They seem to be good at writing checks, but not much else.

 

[jimells]

I just realized we are all looking at this study wrong. We are thinking it is a study of "CFS" criteria, when in reality it is a policy statement. We have been waiting a year for an official response to the IOM and P2P reports, and here it is:

Dear Patients,

We are still going to call your disease "Chronic Fatigue Syndrome" and define it using the Fukuda criteria since "CFS" is still characterized as debilitating fatigue of unknown origin. We have taken the recommendations of the IOM and the P2P panel under advisement, and put those reports back on the shelf to collect dust.

 

[duncan]

The NIH and CDC are both government agencies. When the exceptional medical and research talent is considering a career path, and the choices are government jobs vs high-paying, high-profile private opportunities, which do you think most of the top tier talent will trend towards?

Clue: It likely isn't usually the NIH or the CDC.

 

[Keela Too]

LOL @duncan reminds me what they used to say about teachers:

Good teachers teach, mediocre teachers teach teachers!

 

[jimells]

@Tom Kindlon has already published two comments on PubMed Commons. Way to go, Tom!

http://www.ncbi.nlm.nih.gov/pubmed/26973437#cm26973437_14719

• Tom Kindlon2016 Mar 15 7:46 p.m. (23 hours ago)
  
  Possible errors in Table 4?
  Minor point: I think there is a good chance there are errors in Table 4 in terms of listing which groups are different statistically on some criteria. For example, for both Role Physical and Social Functioning, it says the only differences are between M1 only and M2 only but it looks very likely that M1 only would also be different from M1/M2 given that compared to M2, the scores for M1/M2 are worse again, the SEMs are smaller and the sample size is bigger.
  
  PermalinkShare
• Tom Kindlon2016 Mar 15 5:23 p.m. (yesterday)edited
  
  Depression scores in this follow-up study are very different to scores in original study (looking solely at the Reeves et al. (2005) operationalization)
  Leonard Jason and colleagues previously raised concerns about the Reeves et al. (2005) chronic fatigue syndrome (CFS) criteria [which have also been described as an operationalisation of the Fukuda et al (1994) criteria] (1-4). In particular, Jason and colleagues were concerned that some people who did not have CFS might get diagnosed with CFS using this new set of criteria. They found some evidence to support this concern in a study of those with major depressive disorder who did not have CFS: 38% were found to satisfy these new criteria for CFS(4).
  
  Looking solely at the current study, it would look like there might have been little basis for these concerns. Of 71 people classified with CFS in the current study, only one (1.4%) had a Zung self-rating depression scale (SDS) (5) score of >=60. The mean SDS score for the 71 CFS participants was 44.78 (calculated from the data in Table 4) (6).
  
  However, it should be noted that the SDS (depression) scores in the follow-up study are very different from the scores in the original Georgia cohort(7). Of the 113 people diagnosed with CFS in the original Georgia cohort, data for 112 (99.1%) was published(7). The average SDS score was considerably higher at 56.2. Possibly more revealingly, 40.2% had a SDS score of >=60. As described in the paper, the SDS scale provides an index score and categories reflecting no (<50), mild (50-59), moderate (60-69), and severe (>=70) depression.
  
  I am not sure why there should be such a large difference in a cohort between the initial and follow-up studies in the rate of those with moderate or severe depression (40.2% vs 1.4%). But it does mean that caution should be used in terms of interpreting the findings reported in the current paper and their significance regarding the Reeves et al. (2005) criteria (1,6).
  
  References:
  
  [1]. Reeves WC, Wagner D, Nisenbaum R, Jones JF, Gurbaxani B, Solomon L, Papanicolaou DA, Unger ER, Vernon SD, Heim C. Chronic fatigue syndrome--a clinically empirical approach to its definition and study. BMC Med. 2005 Dec 15;3:19.
  
  [2]. Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The chronic fatigue syndrome; a comprehensive approach to its definition and study. Ann Int Med 1994, 121:953-959.
  
  [3]. Jason LA, & Richman JA. How science can stigmatize: The case of chronic fatigue syndrome. Journal of CFS 2007;14:85-103.
  
  [4]. Jason LA, Najar N, Porter N, Reh C. Evaluating the Centers for Disease Control's empirical chronic fatigue syndrome case definition. Journal of Disability Policy Studies 2009;20;93.
  
  [5]. Zung WW, Richards CB, Short MJ. Self-rating depression scale in an outpatient clinic: further validation of the SDS. Arch Gen Psychiatry.1965;13(6):508-515.
  
  [6]. Unger ER, Lin JM, Tian H, Gurbaxani BM, Boneva RS, Jones JF. Methods of applying the 1994 case definition of chronic fatigue syndrome - impact on classification and observed illness characteristics. Popul Health Metr. 2016 Mar 12;14:5.
  
  [7]. Heim C1, Nater UM, Maloney E, Boneva R, Jones JF, Reeves WC. Childhood trauma and risk for chronic fatigue syndrome: association with neuroendocrine dysfunction. Arch Gen Psychiatry. 2009 Jan;66(1):72-80.
  

 

[Valentijn]

I just realized we are all looking at this study wrong. We are thinking it is a study of "CFS" criteria, when in reality it is a policy statement. We have been waiting a year for an official response to the IOM and P2P reports, and here it is:

To be fair, this paper was probably written and submitted quite a while ago. It can take many months to get to the stage of being published by a journal.

 

[duncan]

I suspect it doesn't predate the launch of the IOM effort, though.

These people probably know how to interpret which way the wind might blow as well as anybody.

 

[anciendaze]

I have not been positively impressed with the ability of these criteria to identify PEM/PENE in any useful way. Would someone who has taken the time to go through the material tell me what role orthostatic intolerance plays in their diagnostic criteria?

I have a distinct impression they are prepared to investigate (chronic fatigue - PEM - OI). What use this might be to anyone is unclear.

 

[alex3619]

I assume the presence of PEM was based on the CDC Symptom Questionairre which I don't think is a good operationalization of PEM. But not sure if that is it.

There is a big risk PEM will be confused with exercise intolerance or regular fatigue. I would want to look carefully at study methodology before drawing conclusions about reliability of this data.

 

[geraldt52]

Giving the CDC $5M for research is like giving your alcoholic uncle $50 for groceries. It may seem like the right thing to do, but only a fool would think that it isn't going to end up as 3 bottles of cheap vodka and 2 packs of cigarettes.

 

[Scarecrow]

Would someone who has taken the time to go through the material tell me what role orthostatic intolerance plays in their diagnostic criteria?

They make no assessment of orthostatic intolerance. The symptoms they ask about in the CDC inventory are below. Some may be vaguely suggestive of an OI problem but that's about as far as it goes.

q1 Sore throat
q2 Tender lymph nodes or swollen glands in your neck or armpits
q3 Diarrhea
q4 Unusual fatigue for at least one day after exertion
q5 Muscle aches or pains
q6 Joint pain
q7 Fever
q8 Chills
q9 Unrefreshing sleep
q10 Sleeping problems
q11 Headaches
q12 Forgetfulness or memory problems
q13 Difficulty thinking or concentrating
q14 Nausea
q15 Stomach or abdominal pains
q16 Sinus or nasal symptoms
q17 Shortness of breath
q18 Eye sensitivity to light
q19 Depression
q20 Another symptom (Please specify: )

Edited: some symptoms scored through to reflect Dolphin's note just below

 

[Dolphin]

They make no assessment of orthostatic intolerance. The symptoms they ask about in the CDC inventory are below. Some may be vaguely suggestive of an OI problem but that's about as far as it goes.

They only report data on the eight Fukuda criteria symptoms not the full list in the CDC symptom inventory.

 

[anciendaze]

Could someone tell them that it is a combination of OI and PEM/PENE in at least a significant percentage of patients which makes it virtually impossible for them to comply with exercise therapy.

When you deteriorate if you spend more than about 4 hours per day upright, you have to drop other activities to participate without harm. What do you drop: eating, bathing, dressing? Do you exercise while supine?

When the effects of exercise last several days, you can't schedule enough sessions during a week to improve. The result is that patients with PEM and OI are considered non-compliant. If you ignore even these patients you are never going to come to grips with the problems of those who are literally bedbound.

This makes me wonder: just what do they think they are studying?