Illness beliefs and treatment outcome in chronic fatigue syndrome, 1998, Deale, Chalder and Wessely

[Jonathan Edwards]

I suspect that the group of patients they saw, and see, is quite different to the group of patients who would be referred by their GP to, say, an infectious disease doctor or an immunologist.

That was my thought. When doing a trial in house, as I have done, it is very easy to pick patients that suit your narrative. For RA we have objectives measures that reflect that selection. Here it is much looser.

 

[Evergreen]

That was my thought. When doing a trial in house, as I have done, it is very easy to pick patients that suit your narrative. For RA we have objectives measures that reflect that selection. Here it is much looser.

Right, so in RA papers you can see at a glance whether selection bias might be affecting results?

As always, the devil is in the detail. This is the detail of Fulcher & White's selection:

In all, 167 outpatients were screened for the study. All had been referred to a chronic fatigue clinic in a general hospital department of psychiatry. All patients with the chronic fatigue syndrome who also had a psychiatric disorder or insomnia were offered treatment for their comorbid disorder. If treatment was successful but the patients still met criteria for the chronic fatigue syndrome they were recruited into the trial. Ninety six patients did not meet criteria for the trial. Of these patients, 74 who had a current psychiatric disorder and three who had insomnia alone usually had their fatigue alleviated by treatment for these conditions. Nine patients had organic causes for their fatigue. A further five patients were not incapacitated enough, and five others were too incapacitated to attend for outpatient treatment. Only five of 71 (7%) eligible patients refused the trial.

Sixty six patients gave valid, informed consent and entered the trial. Of these, 27 (41%) had successfully been treated for a comorbid disorder beforehand but still met criteria for the chronic fatigue syndrome.

In Deale et al. 1997:

Patients were recruited from consecutive referrals by primary care physicians and consultants to a hospital clinic specializing in chronic fatigue syndrome. Each referred patient received a standardized assessment interview with a consultant psychiatrist experienced in chronic fatigue syndrome (S.W.).

They get points for consecutive referrals.

@Hutan , here's the detail of that exclusion:

Of the 142 patients assessed for trial entry, 75 were ineligible: 50 did not meet the positive diagnostic criteria for chronic fatigue syndrome, eight had a primary diagnosis of somatization disorder, four had major depression, one had recently started taking antidepressant medication, and 12 were unable to attend sessions regularly (seven lived too far away or had work commitments, and five were bed bound or dependent on wheelchairs). Of the 67 patients eligible for trial entry, seven (10%) refused; two gave no reason for refusing, three did not wish to be randomized, and two did not wish to have cognitive behavior therapy.

 

[Trish]

Would exclusion of those with somatisation disorder, whatver that is, mean the sample selected primarily experienced fatigue, and not other somatic symptoms such as pain. Given that these were done in the 1990's, they probably used Oxford criteria, which also allowed inclusing of the milder forms of depression and anxiety. So what were they actually studying?

 

[jnmaciuch]

Would exclusion of those with somatisation disorder, whatver that is, mean the sample selected primarily experienced fatigue, and not other somatic symptoms such as pain. Given that these were done in the 1990's, they probably used Oxford criteria, which also allowed inclusing of the milder forms of depression and anxiety. So what were they actually studying?

I had the same question. I’m guessing they were using DSM IV criteria, which came out in 1994:

A. A history of many physical complaints beginning before age 30 years that occur over a period of several years and result in treatment being sought or significant impairment in social, occupational, or other important areas of functioning.

B. Each of the following criteria must have been met, with individual symptoms occurring at any time during the course of the disturbance:

1. four pain symptoms: a history of pain related to at least four different sites or functions (e.g., head, abdomen, back, joints, extremities, chest, rectum, during menstruation, during sexual intercourse, or during urination)
2. two gastrointestinal symptoms: a history of at least two gastrointestinal symptoms other than pain (e.g., nausea, bloating, vomiting other than during pregnancy, diarrhea, or intolerance of several different foods)
3. one sexual symptom: a history of at least one sexual or reproductive symptom other than pain (e.g., sexual indifference, erectile or ejaculatory dysfunction, irregular menses, excessive menstrual bleeding, vomiting throughout pregnancy)
4. one pseudoneurological symptom: a history of at least one symptom or deficit suggesting a neurological condition not limited to pain (conversion symptoms such as impaired coordination or balance, paralysis, or localized weakness, difficulty swallowing or lump in throat, aphonia, urinary retention, hallucinations, loss of touch or pain sensation, double vision, blindness, deafness, seizures; dissociative symptoms such as amnesia; or loss of consciousness other than fainting)

C. Either (1) or (2):

1. after appropriate investigation, each of the symptoms in Criterion B cannot be fully explained by a known general medical condition or the direct effects of a substance (e.g., a drug of abuse, a medication)
2. when there is a related general medical condition, the physical complaints or resulting social or occupational impairment are in excess of what would be expected from the history, physical examination, or laboratory findings

D. The symptoms are not intentionally feigned or produced (as in factitious disorder or malingering).

So….excluding probably everyone who might have met any of the more stringent ME/CFS criteria unless they happened to insist that they didn’t have a certain number of those miscellaneous symptoms. Because I’m sure that the vast majority of pwME would eventually say “okay sure, yeah, I’ve experienced that at some point” if probed with a laundry list of symptoms, especially when they’re being assessed at any time.

The “starting before age 30” criteria also sticks out to me—it would end up excluding most people who have been living with the illness for years that developed it during one of the most common periods for ME.

So I think you’re right that it’s just…people who said they were tired?

 

[rvallee]

Same. My entire outlook on the world before getting ME was a sort of external world sceptic, moral non-realist, post-modernist and post-structuralist outlook.
Basically a lot of buzzwords for saying everything is relative and we can’t even really know if there is anything real or such thing as objective truth.

In a philosophical sense, my only belief is the we cannot know if literally anything is true because every information we have is shaped by our percetions which are in turn shaped by cognitive processes (whatever that means and that’s really upto debate).

What bothers me is the framing of an opinion as a belief. They are not the same, and the opinion that this is a physical problem (in an infectious illness kind of way, not a broken bone one) is rational and arrived at using the facts available, senses, experiences and so on. Framing this as a belief is a choice, one made without actually validating anything. Because beliefs cannot be validated.

But it's framed as beliefs. The questions are very oddly phrased for this reason. Their ambiguity makes it precisely moldable to a desired outcome. Anyone answering the questionnaire might ask "what do you mean by this question?", and the universal answer, of course, is: "answer it as you understand it". So everyone is answering a slightly different question, but it's always interpreted in a particular way. Which they don't share.

But they're not asking about beliefs. They're asking about opinions, while analyzing them as beliefs. Which is highly dishonest.

I can't say I agree that this study is compelling. As a rhetorical device, sure, but scientifically speaking this is biased and useless. It takes prior beliefs to accept the interpretation as they are. Without those beliefs, the interpretation is just weird. Change the people running the study, and you can change the outcome entirely. Same with the participants, but here they are clearly a reflection of the researchers and what they sought. What they sought was confirmation of their model. They were always going to argue in support of it, and the design reflects it.

In my (old) profession, software development, I wouldn't even look at information built in such a lousy way. It's an entirely useless way of assessing knowledge or making decisions. It would be so easy to take random attributions and argue similarly about anything.

 

[Yann04]

It’s very intentional. Every word they pick is thought out with predetermined conclusions.

When they measure inactivity they call it “fear avoidance”, which is assuming an unproven mechanism.
When they measure pain levels they call it “central sensitivity”, assuming an unproven mechanism.
When they measure the effect of symptom burden on mental health, they call it catastrophising.
When they measure idiopathic chronic fatigue, they call it CFS/ME.

Again and again, they use words with much thought, every word they use, thing they measure with questionnaires, comes with unproven underlying assumptions. It’s creation of narratives with survey results. Choose the right surveys, and you can make anything true. The overreliance of medicine on poorly thought out surveys which has so many biases in administration is terrible methodology.

 

[Nightsong]

The service is located at the Maudsley. How many patients would accept a referral to one of the most well-known psychiatric hospitals in the country if they didn't think they had a psychiatric condition? Their patients are almost certainly going to have a much higher rate of psychiatric conditions than ME/CFS patients elsewhere.

 

[SNT Gatchaman]

Choose the right surveys, and you can make anything true

Spoiler: Obligatory Yes Prime Minister

 

[Evergreen]

I have often wondered about these early studies...I suspect that the group of patients they saw, and see, is quite different to the group of patients who would be referred by their GP to, say, an infectious disease doctor or an immunologist.

That was my thought. When doing a trial in house, as I have done, it is very easy to pick patients that suit your narrative. For RA we have objectives measures that reflect that selection. Here it is much looser.

I thought this was a nice illustration of how one centre can be different to others.

In the Trial Management Group minutes from the PACE trial, a number of issues are mentioned regarding King's:

At King’s a larger portion of patients opt for CBT over the trial. King’s also has a higher portion of referral with mis-diagnoses or previous treatment.

King’s has a high number of patients excluded on SF36 scores. This may be an issue of explaining the questionnaire carefully to the patient to ensure that they are describing a typical day.

So patients being referred from King's for the trial wanted CBT, were less disabled and fewer had CFS.

Increasing recruitment at King’s
ACTION 19: to write to the MRC to request permission to increase resources to allow King’s centre to recruit faster in the next two years.
ACTION 20: PIs will further discuss logistics of increasing King’s capacity by 50 or 60 per cent.

King’s
 is now is a position to commit more of his time to PACE as a SSMC consultant now that the waiting list has been reduced at this centre.
 A Specialist Registrar has also been identified at King’s that can also be a PACE dedicated doctor.
King’s increasing the target recruitment by a third.

A particular problem is also noted at King's with regard to recording adverse events:

5. NSAEs should be recorded retrospectively at King’s using data collected on other CRFs and in the medical notes.

This is echoed in the Trial Steering committee minutes:

[redacted] explained that there have been a few issues identified at the King’s site requiring attention, including a number of ineligible participants and missing adverse event data. The King’s team were praised for their hard work in addressing the problems highlighted

My understanding is that King's is the centre Chalder and Wessely are, and were, affiliated with, but am happy to be corrected on that.

 

[Robert 1973]

So what were they actually studying?

I think they were studying whatever they thought had the best chance of producing a positive result, in trials designed to maximise the probability of producing a result which could be reported as positive, with the intention of applying the reported findings to anyone who met their broad criteria, including those who would be unlikely to have been included their trials and may have been excluded.