Chandelier
Senior Member (Voting Rights)
CBT is not an effective treatment for long Covid and postexertional malaise. Response to Sauer et al., 2026, Mark Vink et al.
Mark Vink; Alexandra Vink-Niese
Letter
Dear editor,
We have read the pilot randomized controlled trial by Sauer et al. with interest [1]. It compared 16-weeks of CBT (13 sessions) with the waiting-list. CBT was based on a manual for persistent somatic symptoms, including modification of maladaptive activity patterns (avoidance of physical activity). Evidence that patients suffer from these is not provided. The authors conclude that their study shows the feasibility and preliminary efficacy of CBT for patients with long Covid.
However, there are a number of problems with this study. The objective of a pilot study is to evaluate the feasibility of recruitment, randomization, retention, assessment procedures, etc. It does not evaluate the effectiveness of a treatment [2].
The authors claim that participants were severely affected, yet severely affected patients are too ill to take part in such a study.
“The enrollment rate was relatively low (27.32%)” (p. 9 [1]). However, this is not relatively low. Instead, this is so low that selection bias might be an important issue and suggests that CBT is only acceptable to long Covid patients with comorbid mental health problems.
The study used a waiting list control group even though a basic requirement of a properly designed study is that everything in the control group is the same as in the treatment group apart from the treatment, otherwise you do not know if an improvement is down to the treatment or not. The authors themselves note that not using an active-control condition is a study limitation but why they did not use one, in view of this, is unclear.
A systematic review of CBT for a large number of conditions, including ME/CFS, found that the effect of CBT in studies with a passive-control group was small (effect size of 0.31). Yet if the studies used an active-control group, then the effect was negligible (0.09) [3]. After 16-weeks the study by Sauer et al. even became a study without a control group as those patients also got CBT. In such a study, one cannot come to any conclusions about the effectiveness of any treatment.
1 The authors conclude that CBT was preliminary effective based on an fatigue improvement of 0.35 at the end of treatment. Yet the authors ignore that the p-value was 0.49 which is suggestive that it was not statistically significant. Moreover, an improvement of 0.45 or more is needed for clinical significance which was not reached [4].
No significant improvements were observed regarding the general activity impairment or regarding PEM, either directly after CBT or at 3-months follow-up. Moreover, a “significant increase of activity impairment from post-assessment to follow-up was seen in the CBT group” (p. 5 [1]). This suggests that CBT had a negative instead of a positive effect.
The study also concludes that at “3-month follow-up, no significant effects on fatigue or other primary outcomes were observed” (p. 7 [1]). Would a surgical intervention be effective, if three months after it, your health is back to how bad it was before the operation? Consequently, the study should have concluded that CBT is not effective.
The authors claim that this might be down to the broad definition of postexertional malaise (PEM), comprising symptoms occurring more than 24 h (or even longer) after activity. Yet this is an incomplete definition, as the part about after trivial exertion with delayed recovery and loss of function, is missing [5].
Sauer et al. claim that CBT, which aims to increase physical or mental activity, can lead to improvements in participants with PEM but they then define that as “extended or excessive fatigue after exertion” (p. 7 [1]) even though tiredness after exercise is simply a normal physiological response to exercise. Additionally, as the British National Institute for Health and Clinical Excellence (NICE) concluded in its updated ME/CFS guidelines in 2021, gradually increasing activity or exercise in patients who suffer from PEM, is harmful and therefore contraindicated [6].
The authors also claim that CBT was acceptable to participants, yet for example, there was missing data for three outcome measures at the end of treatment in 65.4%, 63.5% and 65.4% and 86.5%, 90.4% and 90.4% of cases at follow-up. The dropout rate in the therapy group at follow-up was 26% (7÷27) and in their feasibility study it was 50% (32÷64) [7]. Those figures strongly suggest that the treatment was not acceptable to many participants.
The authors also claim that CBT and graded exercise therapy are effective in reducing fatigue severity and functional impairment as well as in improving physical functioning while also being cost-effective and they base that on four ME/CFS studies. However, both treatments do not lead to improvement or recovery in ME/CFS as NICE concluded in 2021 [6].
Conclusion
There are many problems with the study by Sauer et al., including selection bias, a high dropout rate, an extremely high rate of missing data, the use of a passive-control group which crossed-over as well as using 5 primary outcomes without controlling for multiple comparisons. Furthermore, Sauer et al. label CBT preliminary effective, even though it does
2 not lead to improvement of general activity impairment or PEM and at three months follow-up, fatigue is just as bad as at baseline. Moreover, the improvement in fatigue at the end of treatment, which was used to claim preliminary efficacy, might not have been statistically significant and on top of that, it was not clinically significant.
Declaration of competing interest
The authors report no conflicts of interest.
Funding
The authors reported there is no funding associated with the work featured in this article.
References
1. Sauer KS, Bräscher AK, Germer S, et al.. Cognitive-behavioral therapy for post COVID-19 condition: A pilot randomized controlled trial. J Psychosom Res. 2026 Jul 7;210:112920. doi: 10.1016/j.jpsychores.2026.112920.
2. Leon AC, Davis LL, Kraemer HC. The role and interpretation of pilot studies in clinical research. J Psychiatr Res. 2011 May;45(5):626-9. doi:
10.1016/j.jpsychires.2010.10.008. Epub 2010 Oct 28.
3. Fordham B, Sugavanam T, Edwards K, et al.. The evidence for cognitive behavioural therapy in any condition, population or context: a meta-review of systematic reviews and panoramic meta-analysis. Psychol Med. 2021 Jan;51(1):21-29. doi:
10.1017/S0033291720005292.
4. Slotegraaf AI, Gerards MHG, Verburg AC, de van der Schueren MAE, Kruizenga HM, Graff MJL, Cup EHC, Kalf JG, Lenssen AF, Meijer WM, Kool RA, de Bie RA, van der Wees PJ, Hoogeboom TJ; Dutch Consortium Allied Healthcare COVID-19. Evaluation of Primary Allied Health Care in Patients Recovering From COVID-19 at 6-Month Follow-up: Dutch Nationwide Prospective Cohort Study. JMIR Public Health Surveill. 2023 Oct 20;9:e44155. doi: 10.2196/44155.
5. Vink M, Vink-Niese F. Using Exercise Therapy for Long COVID Without Screening for Post-Exertional Symptom Exacerbation Potentially Increases the Risks for Patients Who Suffer from it: A Reanalysis of Three Systematic Reviews. Res Inves Sports Med. 10(5), RISM.000748. 2024. DOI: 10.31031/RISM.2024.10.000748
6. NICE. Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome:
diagnosis and management. NICE guideline [NG206]. Birmingham: NICE (2021). Available online at: https://www.nice.org.uk/guidance/ng206.
7. Huth D, Bräscher AK, Tholl S, et al.. Cognitive-behavioral therapy for patients with post-COVID-19 condition (CBT-PCC): a feasibility trial. Psychol Med. 2024 Apr;54(6):1122-1132. doi: 10.1017/S0033291723002921.
The authors claim that participants were severely affected, yet severely affected patients are too ill to take part in such a study.
“The enrollment rate was relatively low (27.32%)” (p. 9 [1]). However, this is not relatively low. Instead, this is so low that selection bias might be an important issue and suggests that CBT is only acceptable to long Covid patients with comorbid mental health problems.
The study used a waiting list control group even though a basic requirement of a properly designed study is that everything in the control group is the same as in the treatment group apart from the treatment, otherwise you do not know if an improvement is down to the treatment or not. The authors themselves note that not using an active-control condition is a study limitation but why they did not use one, in view of this, is unclear.
A systematic review of CBT for a large number of conditions, including ME/CFS, found that the effect of CBT in studies with a passive-control group was small (effect size of 0.31). Yet if the studies used an active-control group, then the effect was negligible (0.09) [3]. After 16-weeks the study by Sauer et al. even became a study without a control group as those patients also got CBT. In such a study, one cannot come to any conclusions about the effectiveness of any treatment.
1 The authors conclude that CBT was preliminary effective based on an fatigue improvement of 0.35 at the end of treatment. Yet the authors ignore that the p-value was 0.49 which is suggestive that it was not statistically significant. Moreover, an improvement of 0.45 or more is needed for clinical significance which was not reached [4].
No significant improvements were observed regarding the general activity impairment or regarding PEM, either directly after CBT or at 3-months follow-up. Moreover, a “significant increase of activity impairment from post-assessment to follow-up was seen in the CBT group” (p. 5 [1]). This suggests that CBT had a negative instead of a positive effect.
The study also concludes that at “3-month follow-up, no significant effects on fatigue or other primary outcomes were observed” (p. 7 [1]). Would a surgical intervention be effective, if three months after it, your health is back to how bad it was before the operation? Consequently, the study should have concluded that CBT is not effective.
The authors claim that this might be down to the broad definition of postexertional malaise (PEM), comprising symptoms occurring more than 24 h (or even longer) after activity. Yet this is an incomplete definition, as the part about after trivial exertion with delayed recovery and loss of function, is missing [5].
Sauer et al. claim that CBT, which aims to increase physical or mental activity, can lead to improvements in participants with PEM but they then define that as “extended or excessive fatigue after exertion” (p. 7 [1]) even though tiredness after exercise is simply a normal physiological response to exercise. Additionally, as the British National Institute for Health and Clinical Excellence (NICE) concluded in its updated ME/CFS guidelines in 2021, gradually increasing activity or exercise in patients who suffer from PEM, is harmful and therefore contraindicated [6].
The authors also claim that CBT was acceptable to participants, yet for example, there was missing data for three outcome measures at the end of treatment in 65.4%, 63.5% and 65.4% and 86.5%, 90.4% and 90.4% of cases at follow-up. The dropout rate in the therapy group at follow-up was 26% (7÷27) and in their feasibility study it was 50% (32÷64) [7]. Those figures strongly suggest that the treatment was not acceptable to many participants.
The authors also claim that CBT and graded exercise therapy are effective in reducing fatigue severity and functional impairment as well as in improving physical functioning while also being cost-effective and they base that on four ME/CFS studies. However, both treatments do not lead to improvement or recovery in ME/CFS as NICE concluded in 2021 [6].
Conclusion
There are many problems with the study by Sauer et al., including selection bias, a high dropout rate, an extremely high rate of missing data, the use of a passive-control group which crossed-over as well as using 5 primary outcomes without controlling for multiple comparisons. Furthermore, Sauer et al. label CBT preliminary effective, even though it does
2 not lead to improvement of general activity impairment or PEM and at three months follow-up, fatigue is just as bad as at baseline. Moreover, the improvement in fatigue at the end of treatment, which was used to claim preliminary efficacy, might not have been statistically significant and on top of that, it was not clinically significant.
Declaration of competing interest
The authors report no conflicts of interest.
Funding
The authors reported there is no funding associated with the work featured in this article.
References
1. Sauer KS, Bräscher AK, Germer S, et al.. Cognitive-behavioral therapy for post COVID-19 condition: A pilot randomized controlled trial. J Psychosom Res. 2026 Jul 7;210:112920. doi: 10.1016/j.jpsychores.2026.112920.
2. Leon AC, Davis LL, Kraemer HC. The role and interpretation of pilot studies in clinical research. J Psychiatr Res. 2011 May;45(5):626-9. doi:
10.1016/j.jpsychires.2010.10.008. Epub 2010 Oct 28.
3. Fordham B, Sugavanam T, Edwards K, et al.. The evidence for cognitive behavioural therapy in any condition, population or context: a meta-review of systematic reviews and panoramic meta-analysis. Psychol Med. 2021 Jan;51(1):21-29. doi:
10.1017/S0033291720005292.
4. Slotegraaf AI, Gerards MHG, Verburg AC, de van der Schueren MAE, Kruizenga HM, Graff MJL, Cup EHC, Kalf JG, Lenssen AF, Meijer WM, Kool RA, de Bie RA, van der Wees PJ, Hoogeboom TJ; Dutch Consortium Allied Healthcare COVID-19. Evaluation of Primary Allied Health Care in Patients Recovering From COVID-19 at 6-Month Follow-up: Dutch Nationwide Prospective Cohort Study. JMIR Public Health Surveill. 2023 Oct 20;9:e44155. doi: 10.2196/44155.
5. Vink M, Vink-Niese F. Using Exercise Therapy for Long COVID Without Screening for Post-Exertional Symptom Exacerbation Potentially Increases the Risks for Patients Who Suffer from it: A Reanalysis of Three Systematic Reviews. Res Inves Sports Med. 10(5), RISM.000748. 2024. DOI: 10.31031/RISM.2024.10.000748
6. NICE. Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome:
diagnosis and management. NICE guideline [NG206]. Birmingham: NICE (2021). Available online at: https://www.nice.org.uk/guidance/ng206.
7. Huth D, Bräscher AK, Tholl S, et al.. Cognitive-behavioral therapy for patients with post-COVID-19 condition (CBT-PCC): a feasibility trial. Psychol Med. 2024 Apr;54(6):1122-1132. doi: 10.1017/S0033291723002921.
Web | DOI | Unpublished