Daily physical activity of patients with CFS: a systematic review (Evering et al, 10)

Dolphin

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This was being discussed in another thread. I thought I'd give it it's own thread. I've made it easier to read by giving each sentence a paragraph.

Daily physical activity of patients with the chronic fatigue syndrome: a systematic review.

Clin Rehabil. 2010 Oct 13. [Epub ahead of print]

Evering RM, van Weering MG, Groothuis-Oudshoorn KC, Vollenbroek-Hutten MM.

Roessingh Research and Development, Enschede, The Netherlands.

Abstract
Objective: To give an overview of the physical activity level of patients with chronic fatigue syndrome in comparison with asymptomatic controls.

Data sources:
MEDLINE, Web of Science, EMBASE, PsycINFO, Picarta, the Cochrane Controlled Trial Register that is included in the Cochrane Library and reference tracking.

Review methods:
A systematic literature search was conducted focusing on studies concerning physical activity levels of patients with chronic fatigue syndrome compared to controls.

A meta-analysis was performed to pool data of the studies.

Results:
Seventeen studies were included with 22 different comparisons between patients with chronic fatigue syndrome and controls.

Fourteen studies, including 18 comparisons, showed lower physical activity levels in patients with chronic fatigue syndrome as compared to controls.

Four studies, including four comparisons, showed no differences between both groups.

The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects.

The pooled mean coefficient of variation in patients with chronic fatigue syndrome was higher as compared to control subjects (34.3% versus 31.5%), but this difference did not reach significance.

Conclusion:
Patients with chronic fatigue syndrome appear to be less physically active compared with asymptomatic controls.

There is no difference in variation of physical activity levels between patients with chronic fatigue syndrome and healthy control subjects, but the validity and reliability of some methods of measuring physical activity is questionable or unknown.

PMID: 20943713 [PubMed - as supplied by publisher]
 
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The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects.
This adds more weight to the view of studies (therapy trials?) using pretty high-functioning CFS patients. I wonder what the daily physical activity levels for typical ME patients in the community, including the substantial percentage that are severely affected?
 

Sasha

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I think that without knowing what the reviewers used as inclusion criteria - i.e. what definition(s) of CFS made a study eligible to be in their review - it's very hard to comment on this study. If even a few of the studies were showing no difference in activity between cases and controls then I agree that it can't have been ME they were looking at, or at least not a representative sample.

Another waste of research funds. Ironically, they could have done the same study casting a wide net using all CFS diagnostic criteria (Canadian through Reeves) and then done a subset analysis (Canadian vs Reeves etc.). I'd be amazed if Canadian criteria folk weren't hugely more inactive than controls while Reeves criteria folk would show little or no difference. That study, if done, could have demonstrated the pointlessness of the Reeves criteria.
 

Sean

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The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects.
I dream of being able to do 68% of what I used to before getting sick. Indeed, I would be very happy with 50%.
 
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I think that without knowing what the reviewers used as inclusion criteria - i.e. what definition(s) of CFS made a study eligible to be in their review...

..they could have done the same study casting a wide net using all CFS diagnostic criteria (Canadian through Reeves) and then done a subset analysis (Canadian vs Reeves etc.). I'd be amazed if Canadian criteria folk weren't hugely more inactive than controls while Reeves criteria folk would show little or no difference. That study, if done, could have demonstrated the pointlessness of the Reeves criteria.
Unfortunately as there were only 7 studies with daily physical activity levels, there probably weren't enough studies to do a subset analysis - though the results would have been very interesting.
 

Sasha

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Unfortunately as there were only 7 studies with daily physical activity levels, there probably weren't enough studies to do a subset analysis - though the results would have been very interesting.
Possibly, but it would be a question of statistical power given the effect size of the difference - depending on how many studies of each type there were and how big the case/control differences within each study of each type. If the differences are big (i.e. people with Canadian criteria ME hugely incapacitated vs controls but Reeves cases little or no difference) there could still be a statistically significant effect even with few studies and with a large effect size for the Canadian/Reeves difference. It's the sort of thing you have to just try and see. Also depends on the size of the individual studies themselves (the bigger the study, the tighter the confidence interval for each study and the easier to detect differences between studies).

Generally speaking, I think there is potential to use systematic review/meta-analysis comparing other kinds of CFS study doing a Canadian vs Reeves analysis and looking for differences in the outcomes (I'm using C vs R as shorthand for the range of CFS diagnostic criteria). For example, if there were some GET studies done separately on PWCanadian and PCReeves, I'd expect to see beneficial effects of GET in the PCReeves studies perhaps, but harmful effects in the PWCanadian studies.

Really appals me that researchers churn out studies with broad CFS criteria without flagging which patients would also fit e.g. the Canadian criteria. It would be so easy to do within-study subset analysis. V. cheap and easy add-on to any study.
 

Dolphin

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I don't know all the literature but don't think there have been any studies use actometers/pedometers done using the Reeves or Canadian criteria. It would be interesting of course. My guess is most of the studies using actometers/pedometers were done by the Nijmegen group in the Netherlands which might be a biased group of patients (they're big into CBT there - not CBT for a chronic illness but CBT to cure - see manual at: http://www.forums.aboutmecfs.org/sh...-(from-2003)-(Bleijenberg-Prins-amp-Bazelmans)).
 

Esther12

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I was just looking into this paper, and then noticed it had recently been cited in:

Does Cognitive Behavioral Therapy or Graded Exercise Therapy Reduce Disability in Chronic Fatigue Syndrome Patients? Objective Measures Are Necessary
Andrew James Kewley

A systematic review of activity levels
in patients with CFS suggested that subjective reporting
can be substantially biased due to various misperceptions
of physical activity (Evering, van Weering, Groothuis-
Oudshoorn, & Miriam, 2010).
 

biophile

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I was just looking into this paper, and then noticed it had recently been cited in:
Evering et al said:
Differences between outcome assessments could explain differences in outcome results, and might bias comparisons made between different outcome assessments. A first explanation could be that subjective outcome assessments result more often in significant lower physical activity levels due to misperception of physical activity levels in subjects with chronic fatigue syndrome.[18]

Subjective instruments may be biased in patients with chronic fatigue syndrome by cognitions concerning illness and disability.[28,41] Misperception of the physical activity level could magnify the feeling of ill-health and possibly has a maintaining role in the course of the disorder.[34] Such misperceptions can be controlled for by using subjective and objective outcome assessments simultaneously. This gives insight into patients’ discrepancies, exploring between what they think they do and what they really do. Both objective and subjective outcome assessments were used in only three studies. [28,34,41] Fry and Martin[34] found a discrepancy between objective and subjective outcome assessments. Adolescent patients with chronic fatigue syndrome as well as their parents reported reduced physical activity levels in comparison with control subjects, while objective monitoring of the physical activity level did not reveal significant differences between the chronic fatigue syndrome and control group.[34] The other two studies found low correlations between objective and subjective measures in patients with chronic fatigue syndrome indicating discrepancies.[28,41] More insight into this is important as improving awareness is a first important step in reaching behavioural changes, as aimed for in cognitive behavioural therapy.[48]

18. Van Weering M, Vollenbroek-Hutten MM, Kotte EM, Hermens HJ. Daily physical activities of patients with chronic pain or fatigue versus asymptomatic controls. A systematic review. Clin Rehabil 2007; 21: 1007–23.

28. Vercoulen JH, Bazelmans E, Swanink CM et al. Physical activity in chronic fatigue syndrome: assessment and its role in fatigue. J Psychiatr Res 1997; 31: 661–73.

34. Fry AM, Martin M. Cognitive idiosyncrasies among children with the chronic fatigue syndrome: anomalies in self-reported activity levels. J Psychosom Res 1996; 41: 213–23.

41. Van der Werf SP, Prins JB, Vercoulen JH, van der Meer JW, Bleijenberg G. Identifying physical activity patterns in chronic fatigue syndrome using actigraphic assessment. J Psychosom Res 2000; 49: 373–79.

48. Ronda G, Van Assema P, Brug J. Stages of change, psychological factors and awareness of physical activity levels in the Netherlands. Health Promot Int 2001; 16: 305–14.
I have not yet looked at the individual papers cited, nor am I sure whether there is contradictory evidence which was not included in this systematic review or if such evidence exists but is later than 2009/2010. IIRC, some discrepancy or weak correlation is common in other diseases and also in healthy people. CBT/GET could add distortions too, as evidenced in the Dutch trials (patients showing lower than normal activity before therapy, but then reporting less symptoms and less disability after therapy without increases in activity). Not to mention the PACE Trial.

When faced with this problem, CBT/GET researchers such as White et al of PACE, have decided to dismiss objective measures as irrelevant to improvement and recovery, saying that patients are somehow the best judges, despite the rationale of therapy casting doubt on patients perceptions' about their illness. This decision coincides with subjective measures giving better results and objective measures generally showing no significant improvements.

Talk of discrepancies and weak correlations should not distract away from this important finding:
"The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects."

I think in at least some of those seven studies, the controls were sedentary too.
 

Sea

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CBT/GET could add distortions too, as evidenced in the Dutch trials (patients showing lower than normal activity before therapy, but then reporting less symptoms and less disability after therapy without increases in activity). Not to mention the PACE Trial.

When faced with this problem, CBT/GET researchers such as White et al of PACE, have decided to dismiss objective measures as irrelevant to improvement and recovery, saying that patients are somehow the best judges, despite the rationale of therapy casting doubt on patients perceptions' about their illness. This decision coincides with subjective measures giving better results and objective measures generally showing no significant improvements.
That's because their definition of sick is that you believe you're sick and their definition of recovered is that you believe you are much better. You don't need objective tests for that, in fact objective measures only get in the way of their "treatment"

You might be tempted to believe you're still sick if they do objective testing that shows you can't do more than you did before their intervention.
 

Dolphin

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That's because their definition of sick is that you believe you're sick and their definition of recovered is that you believe you are much better. You don't need objective tests for that, in fact objective measures only get in the way of their "treatment"

You might be tempted to believe you're still sick if they do objective testing that shows you can't do more than you did before their intervention.
This is in research so there's a good chance the patients never got their results. If they were genuinely concerned about this, they could not give the patients the results but still report results in research papers.
 

MeSci

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CBT/GET researchers such as White et al of PACE, have decided to dismiss objective measures as irrelevant to improvement and recovery, saying that patients are somehow the best judges, despite the rationale of therapy casting doubt on patients perceptions' about their illness. This decision coincides with subjective measures giving better results and objective measures generally showing no significant improvements.

Talk of discrepancies and weak correlations should not distract away from this important finding:
"The meta-analysis included seven studies and showed a daily physical activity level in patients with chronic fatigue syndrome of only 68% of the physical activity level observed in control subjects."

I think in at least some of those seven studies, the controls were sedentary too.
Yes, but we must remember that we are less active due to a fear of activity. :lol:
 

Esther12

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This was cited above. Not read the full paper, but thought the abstract alone could be of interest.

J Psychiatr Res. 1997 Nov-Dec;31(6):661-73.
Physical activity in chronic fatigue syndrome: assessment and its role in fatigue.
Vercoulen JH, Bazelmans E, Swanink CM, Fennis JF, Galama JM, Jongen PJ, Hommes O, Van der Meer JW, Bleijenberg G.
Author information
Abstract

This paper describes the assessment of physical activity in chronic fatigue syndrome (CFS) and investigated the following questions: Do patients with CFS have low levels of physical activity; is there a relationship between actual level of physical activity and fatigue; can self-report measures adequately assess actual level of physical activity; what is the role of cognitions with respect to physical activity; and are results with respect to physical activity specific to CFS? Three different types of activity measures were used: self-report questionnaires, a 12-day self-observation list, and a motion-sensing device (Actometer) which was used as a reference for actual activity level. Fifty-one patients with CFS, 50 fatigued patients with multiple sclerosis (MS), and 53 healthy subjects participated in this study. Although none of the self-report questionnaires showed high correlations with the Actometer, questionnaires that require simple ratings of specified activities were related to the Actometer and can be used as acceptable substitutes, in contrast to instruments that require general subjective interpretations of activity that had low or non-significant correlations with the Actometer. Actometer results showed that CFS patients and MS patients had similar activity levels and both groups were significantly less active than healthy subjects. Compared to MS patients, CFS patients were more likely to indicate that they had been less active than other persons they knew. Activities which patients expected to result in higher fatigue levels were less frequently performed. Patients with CFS had significantly higher scores on this measure than MS patients and healthy subjects. Low levels of physical activity were related to severe fatigue in CFS but not in MS. In conclusion, although CFS patients have similar low activity levels than MS patients, there are also important differences between both groups: in CFS cognitive factors are more prominently involved in producing the low activity levels than in MS and in CFS patients activity level is related to fatigue but not in MS.
http://www.ncbi.nlm.nih.gov/pubmed/9447571