An open letter to Psychological Medicine, again! by D Tuller et al

[Karen Kirke]

The Chalder scale is one of the most idiotic, unscientific questionnaires I have ever had the misfortune to investigate. It's nonsense on so many levels. Maybe someone like Carolyn Wiltshire could do a demolition job on it.

Lewis et al (2013) critiqued the Chalder Fatigue scale resoundingly in their paper “Clinical characteristics of a novel subgroup of chronic fatigue syndrome patients with postural orthostatic tachycardia syndrome” http://onlinelibrary.wiley.com/doi/...ionid=70907FE210C961680D4EFDB88398E516.f02t02


Here are some quotes:


“Secondly, due to its ‘low ceiling effect’, the Chalder fatigue scale is not a good indicator of change in fatigue levels in patients with CFS.” (p.507)


“Whereas there was a wide range of FIS scores, there appeared to be a ‘low ceiling effect’ with the Chalder fatigue scale (Fig. 2a), in which due to the low range of scores on the Chalder fatigue scale, a high proportion of subjects demonstrated maximum fatigue scores, yet demonstrating highly varied FIS scores. There was a correlation between the two fatigue measuring tools (r = 0.1; r2 = 0.03; P = 0.01); however, 62.5% (n = 105) of subjects scored the maximum score of 7 on the Chalder fatigue scale (physical), whereas the same subjects reported fatigue on the FIS in the range from 44 to 156 (Fig. 2b). Similar results were found for both total and the mental domain of the Chalder fatigue scale.” (p.505)


“The observed ‘low ceiling effect’ with the Chalder fatigue scale in this study was consistent with previous findings [55–57]. Goudsmit et al. noted that 50% of CFS patients scored the highest possible score on this scale, whereas 77% scored the two highest possible scores. The authors noted a marked overlap between patients who rated themselves as moderately or severely ill, yet scored the highest possible score on the Chalder fatigue scale.
We demonstrated here that although there is some correlation between the Chalder fatigue scale and the FIS, there remains a marked discrepancy between what individuals report using the two scales in terms of fatigue. Subjects who reported the maximum possible Chalder fatigue score of 7 also scored a range of FIS scores from 44 to 156. Further research is needed to examine this effect of the Chalder fatigue scale. However in the meantime problems may arise in the clinical setting as those with a maximum score at baseline will not be able to record a change in fatigue during or following treatment and will therefore appear to be unresponsive to therapy.” (p.508)

 

[Lucibee]

I've had a go at unpicking the CFQ on my blog.

First, the fact that it logs change and not absolute values of anything, and that its use as a repeated measures instrument could lead to confusion (it certainly did me): https://lucibee.wordpress.com/2016/04/02/fatigued-by-scales-as-outcome-measures/

Second, a clarification on confusion: https://lucibee.wordpress.com/2017/03/30/more-on-fatigue/

Finally, how that all ties in with "recovery" (or not): https://lucibee.wordpress.com/2017/03/31/even-more-on-fatigue-getting-really-tired-now/

I'm well aware that I've probably just added to the confusion by doing this, but hey!

 

[slysaint]

I'm well aware that I've probably just added to the confusion by doing this, but hey!

taken from your blog (hope you don't mind)
"
I think the problem here is that whenever someone tries to do fancy stats, it somehow mentally legitimises what they are doing and they stop thinking.

Think, people, think! Wake up! It’s not logical!

In my very humble opinion, the CFQ should only ever be used as a diagnostic tool (and probably only to diagnose Chalder Fatigue Syndrome). It is NOT a repeated measures instrument. It does NOT measure absolute fatigue. It is NOT suitable for use as a trial outcome measure."

From what I've read, I agree 100%...........
Chalder Fatigue Syndrome, and possibly the paediatric variety, Crawley Fatigue Syndrome.

 

[Lucibee]

I should have added that the only tool a statistician should use on the CFQ is a sharp stick.

 

[lilpink]

It does NOT measure absolute fatigue. It is NOT suitable for use as a trial outcome measure."

Very true. It has a glass ceiling. I score 11 / 11 (the worst possible score) and yet I know people who are far more debilitated than I, but they would only be able to score 11/11 also. If I were to become worse I would still only score 11/11. It's a completely pointless bit of machinery.

 

[Lucibee]

My latest point was about the CFQ's use as part of the recovery criteria. In essence, it already contains its own measure of recovery, because it asks you to compare yourself "to how you felt when you were last well", so a score of 11 or less (out of 33) should be enough to indicate "recovery" (of sorts), at least on the basis of fatigue symptoms. [Actually, I guess this is why the bimodal score might be better, because then a score of 0 will be more "accurate".]

So there is no need to use scores from a reference population, particularly when that population is being used to determine diagnostic validity and not "wellness" or "recovery" validity. It then becomes increasingly daft to use the upper limits of the scores from that reference population (who are themselves ill - they are visiting their GP after all), as they would not define themselves as "recovered" either.

And all that assumes that trial participants have completed the CFQ as intended, which I would argue there's a good chance they haven't, and are using it to log their progress (or lack of) rather than directly comparing themselves with when they were last well. I posited that some may score themselves at 11/33 because they are no worse than they were a month ago, having already hit the ceiling. But we'll never know that.

 

[Dolphin]

It then becomes increasingly daft to use the upper limits of the scores from that reference population (who are themselves ill - they are visiting their GP after all), as they would not define themselves as "recovered" either.

Note that people weren't necessarily asked about their fatigue levels around the time they visited their GP:

Though people who didn't attend GP in the previous year who would on average be healthier were excluded.

General population participants were registered with five group general practices in the southeast of England chosen to ensure a mix of social class and urban vs. rural distribution. As family doctors in the UK are free of charge, all residents have the right to register. Recruiting representative community samples from general practitioner's lists is a widely used method. Thirty-one thousand, six hundred and fifty-one men and women aged 18–45 registered with the five general practices were asked to take part in the original study (Stage 1) (see Ref. [3]). For this current study, only completed data from those who went to see their general practitioner the following year with either a viral illness or a complaint other than a viral illness were used in this study. More detailed description of the sample and recruitment procedures is reported elsewhere (Stage 2) (see Refs. [18,19]). The 1615 patients used for this study are those who completed all the items of the fatigue scale. Aside from knowing that participants presented to the GP with either an infection or another complaint, no further information regarding medical condition, illness, and general practitioner attendance was sought.

[3] Pawlikowska T, Chalder T, Hirsch SR, Wallace P, Wright DJ, Wessely SC. Population based study of fatigue and psychological distress. BMJ 1994;308:763–6.

 

[Esther12]

Note that people weren't necessarily asked about their fatigue levels around the time they visited their GP:

Though people who didn't attend GP in the previous year who would on average be healthier were excluded.

I'm sure we looked up figures on how many people didn't see their GP in a year, and for the working age population it was a significant portion (presumably tending to be more healthy than those who did attend their GP). Hard to know how that will have affected things.

 

[slysaint]

I watched 'Child of our time' on BBC last night; the children they have been following are now 16. Amongst the things they were looking into was change in sleep patterns, use of mobiles phones, online gaming, stress of exams etc.
They got them to wear monitors, took strands of their hair (this was impressive; they could test for cortisol over several months and saw a spike around exam time), and examined pretty accurate data.

Another programme I sometime watch is Food unwrapped where they often do mini-experiments with groups of people which have a number of measurable tests including testing for 'fitness';

there was also recently a program where a simple 3 minute blood test could reliably show if an illness was bacterial or virus (which could dramatically cut down the number of antibiotics prescribed)....the machine to analyse the test would initially cost £1,000 and then £3 per test and has been around for several years.

My point is that there are a lot of far better, more scientific and accurate means of testing available that do not cost a fortune. There is simply no need for any kind of random questionnaire based measurement.

eta: ie the Chalder Fatigue Questionnaire/scale use as a measuring tool should be scrapped,
and any research trial/study relying on it for their conclusions should be reassessed.
eta2: I think the fitness thing was on Trust Me I'm a doctor not Food Unwrapped

 

[arewenearlythereyet]

I watched 'Child of our time' on BBC last night; the children they have been following are now 16. Amongst the things they were looking into was change in sleep patterns, use of mobiles phones, online gaming, stress of exams etc.
They got them to wear monitors, took strands of their hair (this was impressive; they could test for cortisol over several months and saw a spike around exam time), and examined pretty accurate data.

Another programme I sometime watch is Food unwrapped where they often do mini-experiments with groups of people which have a number of measurable tests including testing for 'fitness';

there was also recently a program where a simple 3 minute blood test could reliably show if an illness was bacterial or virus (which could dramatically cut down the number of antibiotics prescribed)....the machine to analyse the test would initially cost £1,000 and then £3 per test and has been around for several years.

My point is that there are a lot of far better, more scientific and accurate means of testing available that do not cost a fortune. There is simply no need for any kind of random questionnaire based measurement.

I agree with this completely....almost.

There is nothing wrong with questionnaires per se. They can bring valuable general information, particularly in the early stages of research. However they need to be used with caution, have excellent design and not be used in isolation to fudge results.

We are arguing a slightly contradictory argument if we dismiss questionnaires out of hand, since we always say that doctors should listen to the opinion of patients?

The best example I can give is from my field (food). You screen a range of new products for overall acceptance using opinion based questionnaires in very controlled conditions. This screens down a shortlist of likely products, but the general nature of the test means you don't know why it scored what it did. You then follow this up with discriminatory tests that identify levels of particular attributes eg too sweet not sweet enough etc. You then redevelop the product using standard measurements like weight of sweetening agent etc and retest. So it's the combination of subjective opinion with actual si measurements that helps you come to the right answer.

In our case, researchers should pair treatment metrics such as VO2 max, blood levels of hormones or metabolites with a questionnaire that determines opinion. This then adds weight to the evidence and a level of confidence to the results and the design of the experiment.

In my experience you can often equally come unstuck if you pursue a narrow field of investigation without checking against the broader objective. Questionnaires can be a good touchstone to keep you on track.

 

[slysaint]

We are arguing a slightly contradictory argument if we dismiss questionnaires out of hand, since we always say that doctors should listen to the opinion of patients?

That's not what I said or meant............my point was the use of a questionnaire as a definitive scale of measurement.

eta: see added note on my other post.

 

[arewenearlythereyet]

That's not what I said or meant............my point was the use of a questionnaire as a definitive scale of measurement.

Sorry that's not how it read.

I will then say I 100% agree with you that we should use both methodologies.

 

[Snowdrop]

I watched 'Child of our time' on BBC last night; the children they have been following are now 16. Amongst the things they were looking into was change in sleep patterns, use of mobiles phones, online gaming, stress of exams etc.
They got them to wear monitors, took strands of their hair (this was impressive; they could test for cortisol over several months and saw a spike around exam time), and examined pretty accurate data.

Although there will be the issue of how to interpret the data. What does it all mean beyond at exam time people tend to be anxious. Is that a bad thing? It seems kind of normal. Even relating the spike to their test results may not yeild anything clear. There are always so many variables to consider.

 

[Dolphin]

ThunderClap for ME Awareness Day on PACE trial (Facebook/Twitter/Tumblr)
http://forums.phoenixrising.me/inde...al-facebook-twitter-tumblr.51138/#post-844117

Links to:
An open letter to Psychological Medicine, again!
23 March 2017
http://www.virology.ws/2017/03/23/an-open-letter-to-psychological-medicine-again/

 

[AndyPR]

I posted to Action For ME's Facebook page this morning asking whether they will announce if they support this open letter or not....and my post has been deleted...

 

[Yogi]

I posted to Action For ME's Facebook page this morning asking whether they will announce if they support this open letter or not....and my post has been deleted...

That is a disgrace. It was supposed to be at end of April they would issue a statement?

This needs to be publicised so that no-one supports AFME. AFME are actively working against ME patients interests (and on #MEAwarenessday as well).

 

[slysaint]

I posted to Action For ME's Facebook page this morning asking whether they will announce if they support this open letter or not....and my post has been deleted...

Standard practice for them I think; anything they don't like, they simply make it dissappear.

 

[AndyPR]

That is a disgrace. It was supposed to be at end of April they would issue a statement?

This needs to be publicised so that no-one supports AFME. AFME are actively working against ME patients interests (and on #MEAwarenessday as well).

Yup. I can't remember exactly what I put and while it was to the point I don't believe that I was abusive with it.

AfME, showing how much they actually care for PwME...

 

[Yogi]

Yup. I can't remember exactly what I put and while it was to the point I don't believe that I was abusive with it.

AfME, showing how much they actually care for PwME...

Politely ask again. Also ask them why they deleted the first post.

Can we get everyone to ask on AFME on Facebook if you are on it. What they gonna do. Delete everyone.

Let it go viral on #MEAwarenessday that AFME are pwme's number 1 enemy!!

 

[JayS]

They were being praised in the debate in the Scottish Parliament yesterday, weren't they? If any sympathetic ears are listening, the result is they think this is a good charity. Same for newly diagnosed patients, or patients who are new to the 'community.' There are US-based entities that are also attractive to people new to the situation, which caused great frustration in the past. The landscape has changed, for the better, but certain elements of it are quite similar.