Chalder & Knudsen: Long-term sickness absence among patients with chronic fatigue syndrome

[Esther12]

It's a two page nothing paper. Probably better to read the full thing than the bits I pulled out, as it's so shot. Full paper should be available here: http://www.kcl.ac.uk/innovation/groups/projects/cfs/publications/assets/2011/Knudsenlongtermsick.pdf

August 23, 2012

Summary
Chronic fatigue syndrome is associated with high levels of
occupational disability. Consecutive out-patients at a chronic
fatigue syndrome treatment service were studied for
associations between occupational status, symptom severity
and cognitive and behavioural responses to symptoms. All
patients had high symptom levels; however, those on longterm
sickness absence had significantly more physical fatigue
(b = 0.098, P50.05) and worse sleep (b = 0.075, P50.05).
Patients with long-term sickness absence also demonstrated
more embarrassment avoidance cognitions (b = 0.086,
P50.05) and avoidance resting behavioural responses
(b = 0.078, P50.05). Identifying and addressing avoidance
behaviours and cognitions regarding embarrassment in
interventions may enhance the chances of individuals
returning to work.
Declaration of interest
T.C. is an author of self-help books on chronic fatigue.

The measures they used:

Patients were asked about the number of symptoms they were
experiencing from a list of nine commonly reported by patients
with CFS (muscle pain, joint pain, tender neck/armpit glands,
un-refreshing sleep, poor memory, headaches, sore throat, malaise
for 24 hours or more after exertion, and poor concentration). The
number of psychiatric symptoms was assessed by the Revised
Clinical Interview Schedule (CISR).7 As fatigue and psychiatric
disorder commonly co-occur,8 fatigue symptoms in the CISR were
omitted. The level of fatigue was measured by the Chalder Fatigue
Scale.9 This measures physical and mental fatigue producing a
total score between 0 and 11. The Jenkins Sleep Scale was used
to assess sleep problems. The responses are given on a six-point
frequency scale (0–5), giving a total score from 0 to 20.10
The Cognitive and Behavioural Responses Questionnaire
(CBRQ) is a new scale designed to assess patients’ cognitive and
behavioural responses to symptoms.11 It has been validated on
230 patients with CFS (further details available from T.C. on
request) and has been used in patients with multiple sclerosis.11
Previous factor analysis of Likert-scored data revealed five cognitive
subscales and two behavioural subscales. Of the cognitive subscales,
one measures the level of symptom focusing, and four assess how
patients interpret their symptoms (catastrophising, damage
beliefs, fear avoidance and embarrassment avoidance). The two
behavioural response subscales measure all-or-nothing behaviour,
and avoidance/resting behaviour. Descriptions of the subscales
with examples of questions asked are provided in online Appendix
DS1. The internal reliability of the scales on the current sample
was high, with Chronbach’s alpha ranging from 0.70 to 0.88.

The strengths of this study include its clinical setting,
diagnostic procedures and the large amount of detailed
information collected about each patient. The small sample size,
multiple comparisons and the use of stepwise regression raises
the risk of findings occurring by chance (type 1 error). In order
to reduce this risk we carried out the minimum number of
statistical tests required to examine our a priori hypotheses. As
we were only able to look at cross-sectional associations, we
cannot comment on cause and effect. The use of data from a
specialised CFS clinic and the use of a new scale may limit the
generalisability of our results.

When it comes to unemployment and filling in questionnaires related to embarrassment, the inability to comment upon cause and affect seems like an important failing, particualrly as the associations don't seem that strong.

We suggest that cognitive and behavioral responses have a role in
predicting functional outcomes of any chronic illness, although
the contested nature of CFS may increase their importance. This
may accentuate any embarrassment over symptoms or fears that
symptoms may get out of control. Such reactions, when combined
with a tendency towards avoidant responses may contribute to an
increasing spiral of avoidance of all social situations including work.

Good point Trudie. Your quackery, and dishonesty about the efficacy of your treatments for CFS will have made these problems more difficult for those diagnosed with CFS. I don't think this should be used as an excuse to spend more money on your treatments though.

To date there is little evidence on the effectiveness of interventions
to prevent long-term sickness absence and facilitate return
to work in patients with CFS. The results of this study suggest that
identifying and addressing avoidance behaviours and cognitions
regarding embarrassment in interventions for CFS may enhance
the chances of individuals returning to work.

There is some evidence, isn't there Trudie? The £6 million PACE trial which you were a lead author on. Do you remember it? About a month ago, you released a paper which finally made available data showed your cognitive and behavioural treatments were not an effective intervention for returning patients to work.

Some more data available here:

http://bjp.rcpsych.org/content/suppl/2011/08/30/bjp.bp.110.082974.DC1/ds82974.pdf

When you look at the data, it's pretty clear that this paper could have been just half a page: 1) raw data, 2) say that nothing terribly significant or interesting was found, 3) conflict of interests section should mention ties to insurance companies who have a financial incentive to claim that psychological factors keep patients out of work.

Measures of disability in CFS are not very good, measures of things like 'Embarrassment avoidance' are not very good. Diagnosis of CFS is not very clear or objective. This paper is just a collection of questionnaire results from people in different situations, with different health problems, mashed together and analysed for associations. I can't believe how common these sorts of papers are in CFS. If these sorts of associations were found from objective data that we could be confident was free of confounding factors, then that would be of interest - this is just - ugh.

 

[Firestormm]

 

[peggy-sue]

So those that are more sick are off work more.
Sounds.... perfectly normal and reasonable and could have been achieved by looking at records.

I imagine the same finding would be made for any condition.

Are "catastrophising, damage beliefs, fear avoidance and embarrassment avoidance" even valid constructions?
There should be information about validation of the questionnaires that were used. Is it available?

 

[Shell]

How much did they spend on this? How long did it take to come up with "damage beliefs" etc?

 

[Sean]

"embarrassment avoidance cognitions"

Trudie, I'd like you to meet this mirror.


"avoidance resting behavioural responses"

I see self-parody is making a comeback.