Six vs 12 Sessions of Gut-focused Hypnotherapy for Irritable Bowel Syndrome: A Randomized Trial.

Gut-focused hypnotherapy has been shown to be a highly effective treatment for irritable bowel syndrome (IBS) in randomized controlled trials. Previous studies have not only demonstrated long-term efficacy on IBS symptoms, but have also demonstrated improvement in noncolonic symptoms, anxiety, quality of life, and reduced healthcare utilization.2, 3, 4, 5 Recently, it has been suggested that the number of treatment sessions might be an important predictive factor for outcomes. However, this has not been previously studied, and therefore no consensus is available on the optimal volume of sessions. The purpose of this study was to determine if outcomes from an abbreviated course of 6 sessions of gut-focused hypnotherapy were noninferior to those achieved after 12 sessions.

Methods

In a randomized controlled, noninferiority, single-blind trial with a parallel design, all patients referred to the hypnotherapy unit were screened for eligibility, which required fulfillment of the Rome III diagnostic criteria for IBS and National Institute for Clinical Excellence recommended criteria for gut-focused hypnotherapy. Exclusion criteria are detailed in the Supplementary Methods.

Gut-focused Hypnotherapy

Patients were allocated to either 6 or 12 weekly sessions using a computer-generated randomization sequence. After an introductory consultation with the hypnotherapist, patients in both groups received gut-focused hypnotherapy using the Manchester protocol. Apart from the number of sessions, the 2 sessions were similar.

Outcome Measures

Outcomes were assessed using a series of validated questionnaires completed at baseline and at the end of treatment (at 6 weeks for the 6-session group and at 12 weeks for the 12-session group). These questionnaires, described in Supplementary Methods, included the IBS Symptom Severity Score (IBS-SSS), noncolonic symptom score, quality-of-life score, Hospital Anxiety Depression (HAD), and the EQ-5D. The primary outcome was a ≥50-point reduction in the IBS-SSS. The percentage of patients experiencing a ≥30% reduction in the pain severity subscores of the IBS-SSS was also calculated.

Sample Size

To allow for up to a 25% dropout, 450 subjects were required overall to ensure 360 subjects completed the study (180 per group), with an 80% power to detect a noninferiority margin of a 12% difference between the groups.

Statistical Analysis

Data were analyzed using a modified intention-to-treat approach. Multiple imputations using the iterative Markov chain Monte Carlo procedure were used for all missing outcomes data. Analysis of covariance or multiple logistic regression analysis was used to compare outcomes between groups after adjustments for baseline anxiety, depression, and EQ-5D scores; age; sex; and IBS subtype. The noninferiority margin was assessed by examination of the lower limit of the 1-sided 95% confidence intervals (CIs).

Results

The consort flow diagram (Supplementary Figure 1) summarizes recruitment and patient flow throughout the study. Overall, of 448 patients who were included in the modified intention-to-treat analyses, 226 were allocated to 6 sessions and 222 to 12 sessions of hypnotherapy.

Supplementary Figure 1

Consort diagram summarizing recruitment and patient flow throughout the trial.

Baseline characteristics, including patient demographics, IBS severity, noncolonic symptom scores, quality of life scores, HAD, and EQ-5D scores were similar in the 2 randomized groups (Supplementary Table 1).

Supplementary Table 1

Summary of Baseline Characteristics of Patients Randomized to Either 6 and 12 Sessions of Gut-focused Hypnotherapy

	12 Sessions (n = 222)	6 Sessions (n = 226)
Female gender	180 (81.1)	198 (87.6)
Mean age, y (range)	40.5 (17–77)	43.2 (18–90)
IBS type
Diarrhea (IBS-D)	73 (32.9)	87 (38.5)
Constipation (IBS-C)	59 (26.6)	73 (32.2)
Alternating (IBS-A)	90 (40.5)	66 (29.2)
Mean IBS-SSS (SD)	325.4 (86.0)	310.1 (86.0)
Mean noncolonic score (SD)	233.0 (83.5)	230.1 (87.6)
Mean quality of life score (SD)	253.9 (85.6)	261.8 (91.0)
Mean HAD-anxiety score (SD)	11.1 (4.4)	10.5 (4.7)
Mean HAD-depression score (SD)	7.4 (4.3)	7.1 (4.6)
Mean EQ-5D health state score (SD)	0.598 (0.314)	0.605 (0.305)

Values are n (%) unless otherwise defined. SD, standard deviation.

In the modified intention-to-treat analysis, a ≥50 point reduction in IBS-SSS was achieved by 178 of 226 patients (78.8%) after 6 sessions and by 164 of 222 patients (73.9%) after 12 sessions, with evidence of noninferiority (adjusted logistic regression analysis: mean difference, 5.1%; 95% CI, –3% to 13%). Similarly, adjusted logistic regression analysis confirmed noninferiority in the proportion achieving a ≥30% reduction in abdominal pain score (mean difference, 6.3%; 95% CI, –4% to 16%) (Figure 1).

Figure 1

Comparison of the response rates (adjusted for baseline variables) from 6 and 12 sessions of hypnotherapy using different symptom severity endpoints and ≥30% reduction in abdominal pain scores.

Other mean differences in secondary outcomes after 6 and 12 sessions were also similar when compared using adjusted logistic regression analyses (noncolonic symptom score, –7.2 [95% CI, –20.9 to 6.5]; improvement in quality of life scores, 8.9 [95% CI, –3.4 to 21.2]; EQ-5D health state scores, 0.02 [95% CI, –0.021 to 0.064], and HAD-depression, –0.5 [95% CI, –1.1 to 0.1]). However, the mean difference in improvement in EQ-5D visual analog scale and HAD-anxiety were greater after 6 compared with 12 sessions (EQ-5D visual analog scale, 3.3 [95% CI, 0.2–6.4; P =.037]; HAD-anxiety, 0.8 [95% CI, –1.5 to –0.2; P = .01]).

Of 448 patients, 54 (12%) dropped out of the study, with a greater percentage of dropouts from the 12-session group compared with the 6-session group (34 [15%] vs 20 [9%], respectively; P = .042).

Discussion

This study, which is the largest randomized study of gut-focused hypnotherapy to date, suggests that an abbreviated course is at least as effective as our standard approach. Compared with 12 sessions, 6 sessions of hypnotherapy led to similar levels of improvement in IBS symptoms, noncolonic symptoms, anxiety, depression, and quality of life, which were almost identical to outcomes previously reported from our unit. There was a trend for the 6-session regimen to perform slightly better on all endpoints measured, and this reached significance for EQ-5D visual analog scale and anxiety. Importantly, the dropout rate after 6 sessions was lower than after 12 sessions, further strengthening the case for this approach.

Several factors might explain these results. There is less time pressure associated with the 12-session approach, allowing therapists to take their time with treatment. Similarly, for the patient, the end may seem a long way off, and therefore engagement with treatment may not be as strong. Consequently, the abbreviated treatment could plausibly lead to stronger motivation by both patient and therapist. Furthermore, momentum may be an important factor, and the abbreviated regimen allows less time for interruption by unforeseen circumstances such as sickness or holidays.

Limitations of this study include the lack of long-term follow-up data to determine the durability of the effects of the abbreviated hypnotherapy regimen. This could be investigated in future studies. Also, although unlikely, we cannot eliminate the risk of selection bias influencing the dropout rates observed, because some participants may have had preconceptions that 1 of the 2 options might be more effective for them.

Nonetheless, these data suggesting that 6 sessions of hypnotherapy for IBS are at least as effective as 12 have important clinical implications. Six as opposed to 12 sessions could halve the cost of hypnotherapy, double the output of an individual hypnotherapist and unit, and may improve access to this effective form of treatment by making it more attractive to purchasers.