The important outcomes were prioritised by the topic-specific members (TSMs) through ranking methods and further confirmed by the standing Committee before the review was carried out. The Committee discussed the outcomes data and agreed that patient’s quality of life is the most important outcome as IBS is a chronic condition. The Committee also agreed that the use of the IBS-QoL scale for this outcome in the evidence was appropriate as it has been validated and used widely in practice and research.

The Committee discussed the importance of assessing the magnitude of improvement from baseline for the quality of life outcome (mean change from baseline scores) rather than just focussing on the difference between treatment groups (mean difference at endpoint).

The Committee noted that outcomes for IBS symptoms (as reported using the GSRS-IBS scale and the ISB-SS scale) were not useful in evaluating effectiveness of psychological interventions. This is because the aim of psychological interventions is to equip people with skills and techniques to manage their IBS symptoms better in the long-term to improve their quality of life overall. They are not aimed at reducing IBS symptoms.

The Committee agreed that the quality of evidence was mostly of low to very low quality due to a number of factors. All of the included studies have unclear baselines regarding any concomitant treatments for IBS; the study populations of all included studies, apart from 1 (Gaylord 2011), were self-referred, which was subject to selection bias; most included studies did not report reasons for withdrawal or lost to follow-up; finally the definition of the comparator in 2 included studies (Zernicke 2012, Treatment as usual) and (Hunt 2009, Waitlist control) was unclear.

The Committee also discussed the directness of the 6 included publications of 4 studies (3 of which were multiple publications of the same research) on the Computerised Cognitive Behavioural Therapy with Mindfulness and Exposure principles (CCBT-Mindfulness/Exposure) as these were conducted in Sweden. The Committee considered and agreed that the procedures of this particular intervention may not be applicable to UK setting for a number of reasons. The intervention package was in Swedish, and that translating the online materials into English may not be practical and there may be uncertainty around its effectiveness when delivered in different languages. Moreover, in this particular CCBT-Mindfulness/Exposure intervention, the participants have online access to a therapist or psychologist to gain detailed one-to-one advice, which was different to how the CCBT programme (for depression) was delivered in the UK.

The Committee moved on to discuss the 1 included study (Hunt 2009) on Computerised Cognitive Behavioural Therapy with Exposure principles (CCBT-Exposure) and another included study on Mindfulness-based stress reduction (MBSR) (Zernicke 2012). As the definition of the comparator in these 2 studies (waitlist control and treatment as usual, respectively) was unclear, the Committee agreed that the quality of the evidence was of very low quality and there was high uncertainty of the results reported in these 2 studies.

Finally, the Committee agreed that the evidence on Mindfulness group training was very limited (1 small study) and of very low quality due to the unclear baseline and reporting issues on reasons for withdrawal and lost to follow-up.

The Committee discussed the potential benefits of the psychological interventions where only limited evidence was identified.

CCBT-Mindfulness/Exposure:

The Committee acknowledged that the evidence suggested some benefits on quality of life and IBS symptoms at 10-week post treatment, but it failed to illustrate longer-term benefit (12-month follow-up). This could be due to potentially unsustainable benefits of the intervention or due to participants from the comparison group crossing over to the treatment arm after the 10-week treatment period.

Also, the limited evidence for this intervention was from the same study (with multiple publications across different time points) carried out in Sweden. As discussed above, the Committee agreed that currently there is still insufficient evidence to recommend such complex intervention in the UK.

A member of the Committee commented that, Ljotsson 2014 was a study of ‘mechanisms’ where a complex intervention that has found to be effective was “dismantled” to investigate the effectiveness of each component part. As such, it is not an efficacy or effectiveness study comparing intervention with a control.

CCBT-Exposure, MBSR and Mindfulness group training 1 very small study (n=31) suggested a small benefit at 6-weeks on quality of life and IBS symptoms without any further longer term data. The Committee agreed that currently there is still insufficient evidence to recommend CCBT-Exposure.

1 small study (n=75) on Mindfulness group training failed to illustrate benefits on quality of life for both the 10-week and 3-month follow-up time points. The Committee again agreed that currently there is still insufficient evidence to recommend Mindfulness group training.

Finally, 1 small study (n=75) on MBSR illustrated small benefit on the quality of life outcome at 8-week time-point, but the study failed to illustrate benefits on both quality of life and IBS symptoms at 6-month follow-up. The Committee again agreed that currently there is still insufficient evidence to recommend MBSR.

The Committee noted that due to the nature of psychological interventions, there was unlikely to be any treatment-related adverse effects.

No economic evaluations of mindfulness were identified. The Committee considered that mindfulness is usually delivered as part of cognitive behavioural therapy and therefore unlikely to involve any substantial impact on resource use.

No economic evaluations of computer-based cognitive behavioural therapy were included in the review of cost-effectiveness. The Committee considered that CCBT is likely to cost less than other psychological interventions.

The Committee acknowledged that although there is currently insufficient research evidence to recommend CCBT and Mindfulness therapy for the management of IBS, Mindfulness therapy has become increasingly popular in private practice, and widely available and free or commercial self-help websites. The Committee felt strongly that urgent UK-based good quality research on Mindfulness therapy is crucial to provide good quality accurate research data to inform both healthcare professionals and patients regarding the effectiveness of such interventions, so that appropriate standards and recommendations could be made for the NHS.

Therefore, the Committee agreed that a research recommendation should be made for investigating the effectiveness of Mindfulness therapy.