Electronic Letters to:
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eLetters: Electronic letters published:
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How effective is the treatment for CFS?
- Tom P Kindlon (19 October 2008)
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Treating severely affected CFS patients
- Tom P Kindlon (27 November 2008)
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Re: Treating severely affected CFS patients
- Hans Knoop, Jos W.M. van der Meer, and Gijs Bleijenberg. (1 April 2009)
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Tom P Kindlon Irish ME/CFS Association
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tkindlon{at}maths.tcd.ie Tom P Kindlon
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Knoop et al cite pre-existing literature to describe CBT as an "effective treatment" for CFS. They also describe this intervention as an "effective treatment". But what effect size should a treatment have before it is described as an "effective treatment"? Readers of this paper may be interested to know about a recent meta- analysis of the efficacy of CBT for CFS[1]. The studies involved a total of 1371 patients. This involved calculating the size of an effect measure, the Cohen's d value. They calculated d using the following method: "Separate mean effect sizes were calculated for each category of outcome variable (e.g., fatigue self- rating) and for each type of outcome variable (mental, physical, and mixed mental and physical). Studies generally included multiple outcome measures. For all analyses except those that compared different categories or types of outcome variables, we used the mean effect size of all the relevant outcome variables of the study." d was calculated to be 0.48. For anyone unfamiliar with Cohen's d values, they are not bounded by 1; also, the higher the score, the bigger the "effect size" i.e. the more "effective" a treatment was found to be. Cohen's d values are considered to be a small effect size at 0.2, a moderate effect size at 0.5, and a large effect size at 0.8[2]. It is disappointing that this study does not use objective outcome measures as recommended in a review by Whiting et al[3] ""Outcomes such as "improvement," in which participants were asked to rate themselves as better or worse than they were before the intervention began, were frequently reported. However, the person may feel better able to cope with daily activities because they have reduced their expectations of what they should achieve, rather than because they have made any recovery as a result of the intervention. A more objective measure of the effect of any intervention would be whether participants have increased their working hours, returned to work or school, or increased their physical activities." One of the aims of CBT (for CFS) has been said to be "increased confidence in exercise and physical activity"[4] Thus it may be the case that when asked questions about one's ability to do things, such as in the physical functioning subscale of SF-36 (one of the outcome measures), the patients might say that they are "Limited A Little" or "Not Limited At All" but may be just as limited as the control group who say "limited a lot". Another example of why objective measurements are important in studies involving CBT was shown by the authors themselves in a previous study[5]. Their results state that "the level of self-reported cognitive impairment decreased significantly more after CBT than in the control conditions. Neuropsychological test performance did not improve." Tom Kindlon [1] Malouff JM, et al., Efficacy of cognitive behavioral therapy for chronic fatigue syndrome: A meta-analysis. Clinical Psychology Review (2007), doi:10.1016/j.cpr.2007.10.004 [2] Cohen J: Statistical power analysis for the behavioural sciences. Edited by: 2. New Jersey: Lawrence Erlbaum; 1988. [3] Whiting P, Bagnall AM, Sowden AJ, Cornell JE, Mulrow CD, Ramírez G.Interventions for the treatment and management of chronic fatigue syndrome: a systematic review. JAMA. 2001;286:1360-1368 http://jama.ama-assn.org/cgi/content/full/286/11/1360 [4] O'Dowd H, Gladwell P, Rogers CA, Hollinghurst S and Gregory A. Cognitive behavioural therapy in chronic fatigue syndrome: a randomised controlled trial of an outpatient group programme. Health Technology Assessment, 2006, 10, 37, 1-140. [5] Knoop H, Prins JB, Stulemeijer M, van der Meer JW, Bleijenberg G: The effect of cognitive behaviour therapy for chronic fatigue syndrome on self-reported cognitive impairments and neuropsychological test performance. Journal of Neurology and Neurosurgery Psychiatry. 2007 Apr;78(4):434-6. |
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Tom P Kindlon, Information Officer (voluntary position) Irish ME/CFS Association
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tkindlon{at}maths.tcd.ie Tom P Kindlon
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This study found that the "more severely disabled patients benefit less from the self-instructions" (to be more specific, "the treatment effect is more than halved for patients with an SIP8 score of 1 standard deviation above the mean"). The authors suggest that these patients "could perhaps be referred for face-to-face CBT instead." They have previously said (twice in the main text and once in the abstract) that CBT is an "effective treatment" for CFS, referencing Chambers et al[1] (as I pointed out in my previous comment, a recent meta- analysis of CBT for CFS[2] found an effect size of 0.48 suggesting that while CBT may have an effect, saying it is "effective" may be overstating it). The authors did not point out that Chambers et al[2] reported that "very few studies have assessed the effectiveness of interventions for children and young people and for severely affected patients" and "the balance between effectiveness and adverse effects of interventions may be different in more severely affected compared with less severely affected patients and methods of delivery/doses may need to be different". This meant that when NICE guidance[3] was produced, which was partly based on the Chambers et al review[2], it omitted the severely affected from its recommendations on CBT ("Cognitive behavioural therapy (CBT) .. should be offered to people with mild or moderate CFS/ME"). There can also be practical difficulties for more severely disabled CFS patients accessing "face-to-face CBT". Combined these findings suggest that non-CBT based interventions may be required to effectively treat the more severely disabled CFS patients. [1] Chambers D, Bagnall A, Hempel S, Forbes C. Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/ myalgic encephalomyelitis: an updated systematic review. J Roy Soc Med 2006; 99: 506–20. [2] Malouff JM, et al., Efficacy of cognitive behavioral therapy for chronic fatigue syndrome: A meta-analysis. Clinical Psychology Review (2007), doi:10.1016/j.cpr.2007.10.004 [3] National Institute for Health and Clinical Excellence. Clinical guideline CG53. Chronic fatigue syndrome/myalgic encephalomyelitis (or encephalopathy): diagnosis and management. London, NICE, 2007. http://guidance.nice.org.uk/CG53 |
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Hans Knoop , Jos W.M. van der Meer, and Gijs Bleijenberg.
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j.knoop{at}nkcv.umcn.nl Hans Knoop, et al.
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Cognitive behaviour therapy (CBT) is an evidence based intervention for chronic fatigue syndrome (CFS). Two meta-analyses showed that CBT leads to a significant decrease of fatigue and disabilities[1-2] and a full recovery of CFS after CBT is possible[3]. Unfortunately, a substantial number of CFS patients do not profit from CBT. This does not mean that CBT is an ineffective intervention. It only shows that it is not effective for all patients. Nearly all effective medical and psychotherapeutic interventions have non-responders. More severely disabled CFS patients profited less from guided self- instructions. It is important to emphasize that all patients that participated in our study were severely disabled (scoring >700 on the sickness impact scale, SIP). Only patients with an extremely high score on the SIP did not profit from the minimal intervention. Prins et al[4], also using the SIP, found that the level of disabilities at baseline did not predict the response to ‘face to face’ CBT. In another cohort treated with CBT[3] there was no relationship between the level of disabilities at baseline and fatigue after CBT [unpublished data]. On the basis of these findings we concluded that the more severely disabled patients can best be directly referred for ‘face to face’ CBT as there is no indication that they will profit less from the more intensive intervention. There are no controlled studies testing the effectiveness of CBT in patients who are homebound (i.e. continuously bedridden and/or not able to visit an outpatient setting). We think that Chambers et al[5] refer to this group when they state that little is known about the effect of CBT in severely affected patients. This group of ‘severely affected’ patients however differs from the ‘severely disabled’ patients in our study. The latter are severely disabled, but not bedridden and able to visit our treatment centre. We think it will be difficult to motivate homebound patients for behavioural interventions as they tend to have stronger somatic attributions. However, there is no reason to believe and no evidence that the model underlying CBT for CFS[4] could not be used in the treatment of homebound CFS patients. Declaration of interest None Hans Knoop1, Jos W. M. van der Meer2, Gijs Bleijenberg1 1Expert Centre Chronic Fatigue, Radboud University Nijmegen Medical Centre, The Netherlands 2Department of Internal Medicine, Radboud University Nijmegen Medical Centre, The Netherlands [1] Price JR, Mitchell E, Tidy E, Hunot V. Cognitive behaviour therapy for chronic fatigue syndrome in adults. Cochrane Database Syst Rev 2008:CD001027. [2] Malouff JM, et al., Efficacy of cognitive behavioral therapy for chronic fatigue syndrome: A meta-analysis. Clin Psychol Rev 2008; 28:736- 45. [3] Knoop H, Bleijenberg G, Gielissen MFM, van der Meer JWM, White PD. Is a full recovery possible after cognitive behavioural therapy for chronic fatigue syndrome? Psychother Psychosom 2007; 76:171-76. [4] Prins JB, Bleijenberg G, Bazelmans E, et al. Cognitive behaviour therapy for chronic fatigue syndrome: a multicentre randomised controlled trial. Lancet 2001; 357: 841–47. [5] Chambers D, Bagnall A, Hempel S, Forbes C. Interventions for the treatment, management and rehabilitation of patients with chronic fatigue syndrome/myalgic encephalomyelitis: an updated systematic review. J Roy Soc Med 2006; 99: 506–20. |
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