CBT by telephone or web for refractory IBS: the ACTIB trial and its 24-month follow-up

Study at a glance

Everitt and colleagues ran the largest trial of cognitive behavioural therapy for IBS, randomising 558 adults with refractory symptoms from 74 English general practices and three gastroenterology centres to therapist-delivered telephone CBT, web-based CBT with minimal therapist support, or treatment as usual. At 12 months both CBT arms reduced symptom severity and improved work and social functioning compared with usual care. A naturalistic follow-up at 24 months found the telephone arm’s benefit largely sustained while the web arm’s symptom benefit had shrunk to non-significance.

What they did

Participants had clinically significant IBS symptoms for at least 12 months despite first-line therapies. They were recruited between May 2014 and March 2016 and randomised to one of three arms. Telephone CBT involved therapist-delivered sessions; web CBT used an online programme with minimal therapist contact; treatment as usual continued standard care. Participants and therapists could not be blinded, but the chief investigator, outcome assessors and statisticians were. Co-primary outcomes at 12 months were the IBS Symptom Severity Score (IBS-SSS, 0 to 500 scale) and the Work and Social Adjustment Scale (WSAS). The trial was registered (ISRCTN44427879) and funded by the UK National Institute for Health Research. The 24-month study (PMID: 31492643) was a non-prespecified follow-up of the same cohort using the same instruments, with multiple imputation for missing data.

What they found

Of 1,452 people screened, 558 were randomised (76% female, 91% white, mean age 43); 70.1% completed 12-month follow-up. Against a usual-care IBS-SSS of 205.6 at 12 months, telephone CBT scored 61.6 points lower (95% CI 33.8 to 89.5, p < 0.001) and web CBT 35.2 points lower (95% CI 12.6 to 57.8, p = 0.002). WSAS was 3.5 and 3.0 points lower respectively. All secondary outcomes favoured CBT (p ≤ 0.002), and there were no serious adverse reactions.

At 24 months, outcomes were available for 323 (58%) of participants. Telephone CBT remained 40.5 IBS-SSS points below usual care (95% CI 15.0 to 66.0, p = 0.002), but the web CBT difference had fallen to 12.9 points (95% CI -12.9 to 38.8, p = 0.33). WSAS differences persisted for both (3.1 and 1.9 points). A clinically significant IBS-SSS change of at least 50 points from baseline was reported by 71% of telephone-CBT, 63% of web-CBT and 46% of usual-care participants who were followed. The authors concluded that gains were sustained but partially eroded. A 2020 network meta-analysis of 41 psychological-therapy trials found self-administered or minimal-contact CBT (RR of remaining symptomatic 0.61) and face-to-face CBT (RR 0.62) among the best-supported options, while cautioning that risk of bias and funnel-plot asymmetry probably inflate the estimates (PMID: 32276950).

Strengths

• Size, pragmatism and independence. 558 patients, primary-care recruitment, public funding and a usual-care comparator make this far more representative than small specialist-centre studies.
• Blinded assessment and statistics, intention-to-treat analysis with imputation, and validated instruments with a pre-specified 12-month primary timepoint, which is long for IBS trials.
• The design answers a practical question, whether scalable low-contact formats work, rather than only whether CBT works in ideal conditions.
• The 24-month follow-up, even if not pre-specified, is rare and informative about durability.

Limitations

• Participants knew their allocation, and the outcomes are self-reported. Usual care is not an attention-matched control, so the comparison bundles CBT content with therapist time, structure and expectation. The trial cannot say how much of the effect is specific to CBT.
• Attrition: 30% lost at 12 months and 42% at 24 months. Imputation helps but cannot fully rescue a follow-up where those who stayed may differ from those who left.
• The 24-month analysis was not pre-specified, and the web CBT symptom benefit was no longer statistically significant at that point.
• The 61.6-point difference on a 500-point scale is meaningful (50 points is the conventional threshold) but modest; usual-care participants also improved over time.
• Generalisability: the cohort was 91% white and had already failed first-line therapies; whether the same programme helps milder or newly diagnosed IBS, or non-UK populations, is untested.
• Therapist training and fidelity matter. The telephone arm used trained therapists following a specific IBS protocol; a generic CBT course may not reproduce the result.

What it means

The evidence suggests that IBS-specific CBT, delivered by telephone or online, may help people with long-standing symptoms that have not responded to first-line treatment, with benefits on both symptoms and daily functioning that can last a year or more. Telephone delivery with a therapist looks more durable than a mostly self-guided web programme. This is consistent with the 2021 ACG guideline’s conditional suggestion for gut-directed psychotherapies.

Readers should not expect CBT to make IBS disappear; the usual-care group’s 46% rate of clinically significant improvement at 24 months shows how much symptoms move on their own, and the CBT arms added to, rather than replaced, that. Access to therapists trained in gut-directed CBT remains limited, and online programmes vary widely in quality. Anyone whose IBS is affecting work, sleep or social life despite diet and medication should ask a clinician about a referral to a gut-directed CBT programme rather than a generic one.

References

• Everitt HA, Landau S, O’Reilly G, et al. Assessing telephone-delivered cognitive-behavioural therapy (CBT) and web-delivered CBT versus treatment as usual in irritable bowel syndrome (ACTIB): a multicentre randomised trial. Gut. 2019. PMID: 30971419
• Everitt HA, Landau S, O’Reilly G, et al. Cognitive behavioural therapy for irritable bowel syndrome: 24-month follow-up of participants in the ACTIB randomised trial. Lancet Gastroenterol Hepatol. 2019. PMID: 31492643
• Black CJ, Thakur ER, Houghton LA, et al. Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2020. PMID: 32276950