Dataset Information

Components of placebo effect: randomised controlled trial in patients with irritable bowel syndrome.

ABSTRACT:

Objective

To investigate whether placebo effects can experimentally be separated into the response to three components-assessment and observation, a therapeutic ritual (placebo treatment), and a supportive patient-practitioner relationship-and then progressively combined to produce incremental clinical improvement in patients with irritable bowel syndrome. To assess the relative magnitude of these components.

Design

A six week single blind three arm randomised controlled trial.

Setting

Academic medical centre.

Participants

262 adults (76% women), mean (SD) age 39 (14), diagnosed by Rome II criteria for and with a score of > or =150 on the symptom severity scale.

Interventions

For three weeks either waiting list (observation), placebo acupuncture alone ("limited"), or placebo acupuncture with a patient-practitioner relationship augmented by warmth, attention, and confidence ("augmented"). At three weeks, half of the patients were randomly assigned to continue in their originally assigned group for an additional three weeks.

Main outcome measures

Global improvement scale (range 1-7), adequate relief of symptoms, symptom severity score, and quality of life.

Results

At three weeks, scores on the global improvement scale were 3.8 (SD 1.0) v 4.3 (SD 1.4) v 5.0 (SD 1.3) for waiting list versus "limited" versus "augmented," respectively (P<0.001 for trend). The proportion of patients reporting adequate relief showed a similar pattern: 28% on waiting list, 44% in limited group, and 62% in augmented group (P<0.001 for trend). The same trend in response existed in symptom severity score (30 (63) v 42 (67) v 82 (89), P<0.001) and quality of life (3.6 (8.1) v 4.1 (9.4) v 9.3 (14.0), P<0.001). All pairwise comparisons between augmented and limited patient-practitioner relationship were significant: global improvement scale (P<0.001), adequate relief of symptoms (P<0.001), symptom severity score (P=0.007), quality of life (P=0.01). Results were similar at six week follow-up.

Conclusion

Factors contributing to the placebo effect can be progressively combined in a manner resembling a graded dose escalation of component parts. Non-specific effects can produce statistically and clinically significant outcomes and the patient-practitioner relationship is the most robust component.

Trial registration

Clinical Trials NCT00065403.

SUBMITTER: Kaptchuk TJ

PROVIDER: S-EPMC2364862 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature

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Publications

Components of placebo effect: randomised controlled trial in patients with irritable bowel syndrome.

Kaptchuk Ted J TJ Kelley John M JM Conboy Lisa A LA Davis Roger B RB Kerr Catherine E CE Jacobson Eric E EE Kirsch Irving I Schyner Rosa N RN Nam Bong Hyun BH Nguyen Long T LT Park Min M Rivers Andrea L AL McManus Claire C Kokkotou Efi E Drossman Douglas A DA Goldman Peter P Lembo Anthony J AJ

BMJ (Clinical research ed.) 20080403 7651

<h4>Objective</h4>To investigate whether placebo effects can experimentally be separated into the response to three components-assessment and observation, a therapeutic ritual (placebo treatment), and a supportive patient-practitioner relationship-and then progressively combined to produce incremental clinical improvement in patients with irritable bowel syndrome. To assess the relative magnitude of these components.<h4>Design</h4>A six week single blind three arm randomised controlled trial.<h4 ...[more]

PMID: 18390493

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Project description:BackgroundPatients with irritable bowel syndrome (IBS) are often placed on diets guided by food intolerance assays, although these have not been validated. We assessed the effects of individualised diets in patients with IBS guided by a leucocyte activation test.MethodsThis is a parallel-group, double-blind, randomised controlled trial of 58 adults with IBS seen at an academic health centre in Northeast USA. Peripheral venous blood was analysed using a leucocyte activation test; individual foods were reported to produce positive or negative results. Participants were randomised to a 4-week diet with either individualised guidance to eliminate foods with positive assay results and allow foods with negative assay results (intervention), or with individualised guidance, matched in rigour and complexity, to eliminate foods with negative assay results and allow foods with positive assay results (comparison). The primary outcome was between-group differences in the IBS Global Improvement Scale (GIS). Secondary outcomes included reductions in IBS Symptom Severity Scale (SSS) scores and increases in IBS Adequate Relief (AR) and Quality of Life (QOL) scores. An aptamer-based proteomic analysis was conducted in strong responders.ResultsThe intervention group had significantly greater increases in mean GIS score after 4 weeks (0.86 vs comparison; 95% CI 0.05 to 1.67; p=0.04) and 8 weeks (1.22 vs comparison; 95% CI 0.22 to 2.22; p=0.02). The intervention group also had significantly greater reductions in mean SSS score at 4 weeks (-61.78 vs comparison; 95% CI -4.43 to -119.14; p=0.04) and 8 weeks (-66.42 vs comparison; 95% CI -5.75 to -127.09; p=0.03). There were no significant differences between intervention and comparison groups in mean AR or QOL scores. A reduction in neutrophil elastase concentration was associated with reduced symptoms.ConclusionsElimination diets guided by leucocyte activation tests reduced symptoms. These findings could lead to insights into the pathophysiology of IBS.Trial registration numberNCT02186743.

Project description:ObjectivesTo assess the therapeutic effects and safety of Tongxie Yaofang (TXYF) granules vs placebo as an alternative treatment for diarrhoea-predominant irritable bowel syndrome (IBS-D). We hypothesised that TXYF would improve clinical responses among patients with IBS-D.DesignA randomised, double-blind, placebo-controlled, phase II, superiority trial.SettingOutpatients attending the Fangshan Hospital, Beijing University of Chinese Medicine, Beijing, China.Participants96 eligible participants included men and women ranging from late adolescence to middle adulthood (18-65 years), diagnosed with IBS-D according to the Rome IV criteria. In addition, they were required to have an irritable bowel syndrome symptom severity score (IBS-SSS) of at least 75.InterventionsTXYF granules (3.7 g) twice daily (taken orally before meals) or placebo for 8 weeks.Primary and secondary outcomesThe primary outcome was the response rate measured by the change in IBS-SSS compared with baseline at week 8. Secondary outcomes included stool frequency; stool consistency at weeks 4, 8 and 20; and quality of life, anxiety and depression at week 8; and safety was monitored throughout the trial.ResultsThe TXYF and placebo groups each comprised 48 participants. The response rate was not significantly different at week 8 between the two groups (the unadjusted treatment effect estimate (intention-to-treat analysis) was 1.12 (95% CI (0.89, 1.41)), p=0.348). Both groups had a high and similar rate of symptom reduction (79.2% (38/48) vs 70.8% (34/48)). There were no statistically significant differences between the two groups on secondary outcomes, although both groups showed substantial improvements. Adverse events in the TXYF and placebo groups were one (sinus arrhythmia) and two (elevated transaminases, weakly positive faecal occult blood), respectively. No serious adverse events occurred.ConclusionsDespite showing clinically meaningful improvements in IBS-D symptoms and a reasonable safety profile after 8 weeks, no significant differences were observed between the TXYF and placebo groups. This suggests that the severity of IBS-D symptoms in both treatment arms might have decreased over time, regardless of the treatment, and highlights the need to investigate the relationship between IBS-D and patient psychology. Future large-scale, rigorously designed trials with longer treatment and follow-up periods are essential to evaluate the therapeutic effects and safety of TXYF, and to explore the psychological factors.Trial registration numberISRCTN12453166.

Dataset Information

Components of placebo effect: randomised controlled trial in patients with irritable bowel syndrome.

Objective

Design

Setting

Participants

Interventions

Main outcome measures

Results

Conclusion

Trial registration

Publications

Components of placebo effect: randomised controlled trial in patients with irritable bowel syndrome.

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