International guidelines have recommended cognitive behavioural therapy, including acceptance and commitment therapy (ACT), as it offers validated benefits for managing fibromyalgia; however, it is inaccessible to most patients.  This study aimed to evaluate the effect of a 12-week, self-guided, smartphone-delivered digital ACT programme on fibromyalgia management.

In the PROSPER-FM randomised clinical trial conducted at 25 US community sites, adult participants aged 22–75 years with fibromyalgia were recruited and randomly assigned (1:1) to the digital ACT group or an active control group that offered daily symptom tracking and monitoring and access to health-related and fibromyalgia-related educational materials. Randomisation was done with a web-based system in permuted blocks of four at the site level. We used a blind-to-hypothesis approach in which participants were informed they would be randomly assigned to one of two potentially effective therapies under evaluation. Research staff were not masked to group allocation, with the exception of a masked statistics group while preparing statistical programming for the interim analysis. The primary endpoint was patient global impression of change (PGIC) response rate at week 12. Analyses were by intention to treat. The trial was registered with ClinicalTrials.govNCT05243511 (now fully closed).

Between Feb 8, 2022, and Feb 2, 2023, 590 individuals were screened, of whom 275 (257 women and 18 men) were randomly assigned to the digital ACT group (n=140) and the active control group (n=135). At 12 weeks, 99 (71%) of 140 ACT participants reported improvement on PGIC versus 30 (22%) of 135 active control participants, corresponding to a difference in proportions of 48·4% (95% CI 37·9–58·9; p<0·0001). No device-related safety events were reported.

The authors concluded that digital ACT was safe and efficacious compared with digital symptom tracking in managing fibromyalgia in adult patients.


These conclusions might well be valid – but then again, they might not!

Here is why I have my doubts:

  • The patients treated with digital ACT knew that they were getting a novel and thus exciting treatment.
  • The patients randomised to the control group, on the other hand, would most likely be disappointed not to receive this therapy. In other words, there were high expectations in the experimental group and disappointment in the control group.
  • In addition, the unmasked researchers would have had the ambition that their innovation would be successful. Thus they would have used verbal and non-verbal communications with the ACT patients to bring about the desired result.

It is therefore conceivable – I think even likely – that these factors would add up to generate a false-positive finding, particularly since the endpoint was entirely subjective.
In view of all this, I am surprised that a journal like THE LANCET has published such a flimsy study with such a over-optimistic conclusion, and I suggest re-phrasing the conclusions as follows:

Digital ACT seemed safe and effective compared with digital symptom tracking in managing fibromyalgia in adult patients. However, due to the design of the study, it is possible that digital ACT is entirely ineffective and the positive outcome is caused by a number of context effects.

6 Responses to Digital behavioural therapy for fibromyalgia?

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