Placebo effects and their determinants in gastrointestinal disorders

Lansoprazole for persistent throat symptoms in secondary care: the TOPPITS RCT

BACKGROUND

Persistent throat symptoms are commonly attributed to 'laryngopharyngeal reflux'. Despite a limited evidence base, these symptoms are increasingly being treated in primary care with proton pump inhibitors.

OBJECTIVE

To assess the value of proton pump inhibitor therapy in patients with persistent throat symptoms.

DESIGN

This was a double-blind, placebo-controlled, randomised Phase III trial.

SETTING

This was a multicentre UK trial in eight UK ear, nose and throat departments.

PARTICIPANTS

A total of 346 participants aged ≥ 18 years with persistent throat symptoms and a Reflux Symptom Index score of ≥ 10, exclusive of the dyspepsia item, were recruited.

INTERVENTION

Random allocation (1 : 1 ratio) to either 30 mg of lansoprazole twice daily or matched placebo for 16 weeks.

MAIN OUTCOME MEASURE

Symptomatic response (i.e. total Reflux Symptom Index score after 16 weeks of therapy).

RESULTS

A total of 1427 patients were screened and 346 were randomised. The mean age was 52 years (standard deviation 13.7 years, range 20-84 years); 150 (43%) participants were male and 196 (57%) were female; 184 (53%) participants had a mild Reflux Symptom Index minus the heartburn/dyspepsia item and 162 (47%) had a severe Reflux Symptom Index minus the heartburn/dyspepsia item. A total of 172 patients were randomised to lansoprazole and 174 were randomised to placebo.

MAIN OUTCOMES

A total of 267 participants completed the primary end-point visit (lansoprazole, n = 127; placebo, n = 140), of whom 220 did so between 14 and 20 weeks post randomisation ('compliant' group); 102 received lansoprazole and 118 received placebo. The mean Reflux Symptom Index scores at baseline were similar [lansoprazole 22.0 (standard deviation 8.0), placebo 21.7 (standard deviation 7.1), overall 21.9 (standard deviation 7.5)]. The mean Reflux Symptom Index scores at 16 weeks reduced from baseline in both groups [overall 17.4 (standard deviation 9.9), lansoprazole 17.4 (standard deviation 9.9), placebo 15.6 (standard deviation 9.8)]. Lansoprazole participants had estimated Reflux Symptom Index scores at 16 weeks that were 1.9 points higher (worse) than those of placebo participants (95% confidence interval -0.3 to 4.2; padj = 0.096), adjusted for site and baseline severity.

SECONDARY OUTCOMES

Ninety-five (43%) participants achieved a Reflux Symptom Index score in the normal range (< 12) at 16 weeks: 42 (41%) in the lansoprazole group and 53 (45%) in the placebo group. A total of 226 participants completed the end-of-trial follow-up visit (lansoprazole, n = 109; placebo, n = 117), of whom 181 were 'compliant'. The mean Reflux Symptom Index scores at 12 months reduced from baseline in both groups [lansoprazole 16.0 (standard deviation 10.8), placebo 13.6 (standard deviation 9.6), overall 14.7 (standard deviation 10.2)]. A total of 87 (48%) participants achieved a Reflux Symptom Index score in the normal range at 12 months: 33 (40%) in the lansoprazole group and 54 (55%) in the placebo group. Likewise, the Comprehensive Reflux Symptom Score and Laryngopharyngeal Reflux - Health Related Quality of Life total scores and subscales all showed very similar changes in the lansoprazole and placebo cohorts at both 16 weeks and 12 months.

LIMITATIONS

Drop-out rate and compliance are issues in pragmatic clinical trials. The Trial Of Proton Pump Inhibitors in Throat Symptoms (TOPPITS) aimed to detect clinically relevant difference with 90% power. The 346 randomised participants reduced to 283 at the primary end point; 267 completed the primary outcome measure, 220 within the protocol time scale. Despite this, the powers to detect the clinically relevant difference in Reflux Symptom Index score at 16 weeks were 82% (compliant comparison) and 89% (pragmatic comparison). The lack of difference between lansoprazole and placebo is generalisable across NHS clinics.

CONCLUSIONS

Participants on lansoprazole did not report significantly better outcomes than participants on placebo on any of the three patient-reported outcome tools (Reflux Symptom Index, Comprehensive Reflux Symptom Score and Laryngopharyngeal Reflux - Health Related Quality of Life). This multicentre, pragmatic, powered, definitive Phase III trial found no evidence of benefit for patients by treating persistent throat symptoms with lansoprazole.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN38578686 and EudraCT number 2013-004249-17.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 3. See the NIHR Journals Library website for further project information.

Paediatric functional abdominal pain disorders

Paediatric functional abdominal pain disorders, currently referred to as disorders of gut-brain interaction, comprise irritable bowel syndrome, functional dyspepsia, abdominal migraine and functional abdominal pain not otherwise specified, as defined by the Rome IV diagnostic criteria. Functional abdominal pain disorders are common disorders with a prevalence of 3-16% depending on country, age and sex. A greater understanding of aetiopathogenesis and pathophysiology is emerging and includes intestinal components (inflammation, motility and the microbiota), central factors (psychological aspects, sensitization and/or differences in connectivity or activity of certain brain regions) as well as extrinsic factors (infections). In particular, the timing of disruption of the microbiota-gut-brain axis seems to be important. Diagnosis is challenging but is primarily based on clinical symptoms and exclusion of other organic causes, with an emphasis on avoiding unnecessary invasive diagnostic procedures. The available pharmacological interventions are limited in children and, therefore, management has focused on combined approaches, including mind-targeted interventions (hypnotherapy and cognitive behavioural therapy), diet (probiotics) and percutaneous electrical nerve field stimulation. The evidence for their clinical efficacy, although limited, is favourable, with positive impacts on symptoms and overall quality of life. The coming decades hold promise for improved understanding and management of these enigmatic disorders.

Treatment expectations seem to affect bowel health when using acupuncture during radiotherapy for cancer: Secondary outcomes from a clinical randomized sham-controlled trial

OBJECTIVE

To investigate if frequent stools ("diarrhoea"), infrequent stools ("constipation"), capacity in daily activities and Quality of Life (QoL) differed between patients treated with verum or sham acupuncture, and if patients with more positive treatment expectations differed regarding frequent stools and infrequent stools from patients with less positive treatment expectations.

METHODS

In this randomized sham controlled trial, 200 patients received verum traditional penetrating acupuncture or sham acupuncture using a telescopic non-penetrating sham-needle 2-3 times a week during abdominal-pelvic radiotherapy (12 needling sessions during median 5 radiotherapy weeks). The patients registered stool frequency once a week, and registered capacity in daily activities and QoL at the start and end of radiotherapy, and at a one-month follow-up.

RESULTS

In the verum acupuncture group, 29 of 96 answering patients (30 %) experienced frequent stools and 7 (7 %) experienced infrequent stools at least one week of radiotherapy. In the sham acupuncture group, 21 of 97 (22 %) experienced frequent stools (p = 0.175) and 10 (10 %) experienced infrequent stools (p = 0.613). Patients with low treatment expectancy were more likely than other patients to experience frequent stools (60 % versus 26 %, p = 0.014) but not to experience infrequent stools (25 % versus 12 %, p = 0.334).

CONCLUSION

Penetrating acupuncture was not effective for frequent stools or for infrequent stools and did not improve capacity in daily activities or QoL in patients undergoing pelvic-abdominal irradiation for cancer more than non-penetrating acupuncture. Since patients with low acupuncture treatment expectations were more likely to experience frequent stools compared to other patients, non-specific treatment effects warrant further studies.

Nocebo effect and biosimilars in inflammatory bowel diseases: what's new and what's next?

INTRODUCTION

The use of biosimilars for the treatment of patients with chronic inflammatory bowel diseases (IBD) showed to be a valid strategy to reduce the economic burden of biologics on health-care costs and to increase patient access to treatment. However, the nocebo effect constitutes an important limitation to the wide use of biosimilars.

AREAS COVERED

We conducted a literature overview to summarize information on nocebo effect in IBD population and to provide physicians with practical key strategies to prevent the nocebo effect in daily clinical practice and to improve patients' outcomes.

EXPERT OPINION

Despite the proven efficacy and safety of biosimilars, further clinical studies are needed to define the effects of reverse and multiple switches in the management of patients with IBD. The development of new subcutaneous formulations, better accepted by patients, could contribute to reduce patients' negative expectations, and limit the nocebo effect.

Placebo Responses and Placebo Effects in Functional Gastrointestinal Disorders

Much has been written about the placebo effects in functional gastrointestinal disorders (FGD), especially in irritable bowel syndrome (IBS), driven by the early hypothesis that in randomized controlled trials (RCTs) of IBS, the placebo effect might be specifically high and thus, corrupts the efficacy of novel drugs developed for this condition. This narrative review is based on a specific search method, a database (www.jips.online) developed since 2004 containing more than 4,500 papers (data papers, meta-analyses, systematic reviews, reviews) pertinent to the topic placebo effects/placebo response. Three central questions-deducted from the body of current literature-are addressed to explore the evidence behind this hypothesis: What is the size placebo effect in FGD, especially in IBS, and is it different from the placebo effect seen in other gastrointestinal disorders? Is the placebo effect in FGD different from other functional, non-intestinal disorders, e.g. in other pain syndromes? Is the placebo effect in FGD related to placebo effects seen in psychiatry, e.g. in depression, anxiety disorders, and alike? Following this discussion, a fourth question is raised as the result of the three: What are the consequences of this for future drug trials in FGD? In summary it is concluded that, contrary to common belief and discussion, the placebo effect seen in RCT in FGD is not specifically high and extraordinary as compared to other comparable (i.e. functional) disorders. It shares less than expected commonalities with the placebo effect in psychiatry, and very few predictors have yet been identified that determine its effect size, especially some that are driven by design features of the studies. Current practice of RCT in IBS seems to limit and control the placebo effect quite well, and future trial practice, e.g. head-to-head trial, still offers options to maintain this control, even in the absence of placebos used.

Randomised clinical trial: minesapride vs placebo for irritable bowel syndrome with predominant constipation

BACKGROUND

Agonists of 5-hydroxytryptamine 4 receptor are potential agents for irritable bowel syndrome with predominant constipation (IBS-C). However, only tegaserod has been approved for a very limited population in the US.

AIM

To evaluate the efficacy and safety of minesapride in patients with Rome IV defined IBS-C.

METHODS

A double-blind, placebo-controlled, dose-finding study was performed. Overall, 411 patients were randomised to receive minesapride at 10, 20 or 40 mg/d, or placebo for 12 weeks. The primary endpoint was Food and Drug Administration (FDA) composite endpoint (responder: a patient who reported an increase in one or more complete spontaneous bowel movements from baseline and improvement of ≥30% from baseline in weekly average of worst abdominal pain score, both in the same week for ≥6/12 weeks).

RESULTS

The FDA composite responder rate was 13.6% (14/103) in the placebo group, 13.6% (14/103) in the 10 mg group, 19.2% (20/104) in the 20 mg group and 14.9% (15/101) in the 40 mg group, and no dose-response relationship was found. A greater percentage of minesapride 40 mg-treated patients than placebo-treated patients met both responder requirements for ≥9/12 weeks as the stricter composite evaluation (P < 0.05). Furthermore, minesapride 40 mg significantly increased SBM frequency compared with placebo (adjusted P < 0.001 at Week 12). The most common adverse event was mild diarrhoea.

CONCLUSIONS

Minesapride was safe and well-tolerated. Although the primary endpoint was negative, minesapride 40 mg is likely to improve the stricter composite endpoint and SBM frequency. Japan Pharmaceutical Information Center Number: Japic CTI-163459.

Randomised clinical trial: faecal microbiota transplantation versus autologous placebo administered via colonoscopy in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) has been associated with microbial dysbiosis.

AIM

To investigate the efficacy of faecal microbiota transplantation (FMT) in the treatment of IBS.

METHODS

Forty-nine IBS patients were randomised to receive autologous or allogenic FMT via colonoscopy. The primary endpoint was a sustained, minimum of 50-point, reduction in the IBS Symptom Severity Score. The secondary outcomes were levels of anxiety and depression, changes in quality of life, gut microbiota and faecal water content as assessed with validated questionnaires, intestinal microbiota composition and stool dry weight.

RESULTS

The primary endpoint was not achieved in either group. However, there was a transient reduction in the mean IBS Symptom Severity Score in the FMT group at 12 weeks after treatment as compared to baseline (P = 0.01). The groups did not differ in the number of patients achieving clinical response at 12 weeks. In the FMT-treated patients, microbial composition had changed to resemble that of the donor and the stool water content decreased significantly compared to baseline. The depression score decreased in patients with a reduction in IBS symptoms after FMT, but not in those placebo-treated patients who experienced a reduction in IBS symptoms.

CONCLUSIONS

FMT provided only a transient relief of symptoms, although it induced a sustained alteration in the microbiota of IBS patients. Therefore, FMT delivered by a single infusion via colonoscopy cannot be recommended as a treatment for IBS in clinical practice. ClinicalTrials.Org, Trial registration number: NCT03561519.

Non-specific effects of acupuncture and sham acupuncture in clinical trials from the patient's perspective: a systematic review of qualitative evidence

BACKGROUND

Previous clinical trials have demonstrated that both acupuncture and sham acupuncture exert significant, non-specific effects on treatment outcomes when compared to no-treatment controls. A recently developed framework (mechanisms in orthodox and complementary and alternative medicine-MOCAM) suggests that the non-specific effects of acupuncture originate from multiple domains (e.g. patient characteristics, acupuncturist skill/technique, the patient-acupuncturist relationship, and the acupuncture environment). However, it remains to be determined precisely how these domains influence the non-specific effects of treatment among patients receiving acupuncture and sham acupuncture in clinical trials. Therefore, we conducted a systematic review to synthesize existing qualitative evidence on how trial participants randomized to acupuncture and sham acupuncture groups experience non-specific effects, regardless of the types of medical condition investigated.

METHODS

This systematic review included primary qualitative studies embedded in randomized controlled trials designed to investigate acupuncture or sham acupuncture interventions. Eligible studies published in English were derived from a search of five international databases. The methodological quality of included studies was evaluated using the Critical Appraisal Skills Programme (CASP) tool. Using a framework synthesis approach, the identified MOCAM framework was adapted based on the synthesis of the available qualitative evidence.

RESULTS

A total of 20 studies of high methodological quality were included. Our proposed model indicated that the effects of acupuncture may be increased by maintaining a professional status, applying a holistic treatment approach, practicing empathy, and providing patients with an appropriate explanation of the theory behind acupuncture and sham acupuncture. From the patient's perspective, the efficacy of treatment can be increased by following the lifestyle modification advice provided by acupuncturists, maintaining a positive attitude toward treatment efficacy, actively engaging with acupuncturists during consultation, and making behavioral changes based on experience gained during the trial.

CONCLUSION

The results of this study may provide a basis for improving and standardizing key components of non-specific effects in acupuncture treatment, and for improving the isolation of specific effects in future clinical trials involving acupuncture and sham acupuncture.

Stress and the brain-gut axis in functional and chronic-inflammatory gastrointestinal diseases: A transdisciplinary challenge

The broad role of stress in the brain-gut axis is widely acknowledged, with implications for multiple prevalent health conditions that are characterized by chronic gastrointestinal symptoms. These include the functional gastrointestinal disorders (FGID), such as irritable bowel syndrome and functional dyspepsia, as well as inflammatory bowel diseases (IBD) like ulcerative colitis and Crohn's disease. Although the afferent and efferent pathways linking the gut and the brain are modulated by stress, the fields of neurogastroenterology and psychoneuroendocrinology (PNE)/ psychoneuroimmunology (PNI) remain only loosely connected. We aim to contribute to bringing these fields closer together by drawing attention to a fascinating, evolving research area, targeting an audience with a strong interest in the role of stress in health and disease. To this end, this review introduces the concept of the brain-gut axis and its major pathways, and provides a brief introduction to epidemiological and clinical aspects of FGIDs and IBD. From an interdisciplinary PNE/PNI perspective, we then detail current knowledge regarding the role of chronic and acute stress in the pathophysiology of FGID and IBD. We provide an overview of evidence regarding non-pharmacological treatment approaches that target central or peripheral stress mechanisms, and conclude with future directions, particularly those arising from recent advances in the neurosciences and discoveries surrounding the gut microbiota.

Effects of Low FODMAP Diet on Symptoms, Fecal Microbiome, and Markers of Inflammation in Patients With Quiescent Inflammatory Bowel Disease in a Randomized Trial

BACKGROUND & AIMS

There is limited evidence that a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) reduces gut symptoms in quiescent inflammatory bowel disease (IBD). We performed a randomized, controlled trial to investigate the effects of a low FODMAP diet on persistent gut symptoms, the intestinal microbiome, and circulating markers of inflammation in patients with quiescent IBD.

METHODS

We performed a single-blind trial of 52 patients with quiescent Crohn's disease or ulcerative colitis and persistent gut symptoms at 2 large gastroenterology clinics in the United Kingdom. Patients were randomly assigned to groups that followed a diet low in FODMAPs (n = 27) or a control diet (n = 25), with dietary advice, for 4 weeks. Gut symptoms and health-related quality of life were measured using validated questionnaires. Stool and blood samples were collected at baseline and end of trial. We assessed fecal microbiome composition and function using shotgun metagenomic sequencing and phenotypes of T cells in blood using flow cytometry.

RESULTS

A higher proportion of patients reported adequate relief of gut symptoms following the low FODMAP diet (14/27, 52%) than the control diet (4/25, 16%, P=.007). Patients had a greater reduction in irritable bowel syndrome severity scores following the low FODMAP diet (mean reduction of 67; standard error, 78) than the control diet (mean reduction of 34; standard error, 50), although this difference was not statistically significant (P = .075). Following the low FODMAP diet, patients had higher health-related quality of life scores (81.9 ± 1.2) than patients on the control diet (78.3 ± 1.2, P = .042). A targeted analysis revealed that in stool samples collected at the end of the study period, patients on the low FODMAP diet had significantly lower abundance of Bifidobacterium adolescentis, Bifidobacterium longum, and Faecalibacterium prausnitzii than patients on control diet. However, microbiome diversity and markers of inflammation did not differ significantly between groups.

CONCLUSIONS

In a trial of the low FODMAP diet vs a control diet in patients with quiescent IBD, we found no significant difference after 4 weeks in change in irritable bowel syndrome severity scores, but significant improvements in specific symptom scores and numbers reporting adequate symptom relief. The low FODMAP diet reduced fecal abundance of microbes believed to regulate the immune response, compared with the control diet, but had no significant effect on markers of inflammation. We conclude that a 4-week diet low in FODMAPs is safe and effective for managing persistent gut symptoms in patients with quiescent IBD. www.isrctn.com no.: ISRCTN17061468.

The influence of personality traits on the placebo/nocebo response: A systematic review

OBJECTIVE

Some people might be more prone to placebo and nocebo responses than others depending on their personality traits. We aimed to provide a systematic review on the influence of personality traits on placebo and nocebo responses in controlled and uncontrolled studies.

METHODS

We conducted a systematic literature search in the databases CINAHL, AMED, PsycINFO and EMBASE for relevant publications published between January 1997 and March 2018. For all included papers, we conducted an additional forward search.

RESULTS

After screening 407 references, we identified 24 studies. The Big Five (i.e., neuroticism, extraversion, openness to experience, agreeableness and conscientiousness) and optimism were the most frequently investigated personality traits. Several studies found a positive association between optimism and the placebo response. Furthermore, we found that higher anxiety was associated with increased nocebo responses.

CONCLUSION

Evidence points to a possible association between optimism and the placebo response. Therefore, further emphasising the investigation of the influence of optimism on the placebo/nocebo response seems warranted. For clinical practice, the impact of anxiety on the nocebo response might be important to identify patients who might be more prone to experiencing side effects of medical treatments.

The Clinical Implications of Nocebo Effects for Biosimilar Therapy

Nocebo effects encompass negative responses to inert interventions in the research setting and negative outcomes with active treatments in the clinical research or practice settings, including new or worsening symptoms and adverse events, stemming from patients' negative expectations and not the pharmacologic action of the treatment itself. Numerous personality, psychosocial, neurobiological, and contextual/environmental factors contribute to the development of nocebo effects, which can impair quality of life and reduce adherence to treatment. Biologics are effective agents widely used in autoimmune disease, but their high cost may limit access for patients. Biosimilar products have gained regulatory approval based on quality, safety, and efficacy comparable to that of originator biologics in rigorous study programs. In this review, we identified gaps in patients' and healthcare professionals' awareness, understanding, and perceptions of biosimilars that may result in negative expectations and nocebo effects, and may diminish their acceptance and clinical benefits. We also examined features of nocebo effects with biosimilar treatment that inform research and clinical practices. Namely, when biosimilars are introduced to patients as possible treatment options, we recommend adoption of nocebo-reducing strategies to avoid negative expectations, including delivery of balanced information on risk-benefit profiles, framing information to focus on positive attributes, and promoting shared decision-making processes along with patient empowerment. Healthcare professionals confident in their knowledge of biosimilars and aware of bias-inducing factors may help reduce the risk of nocebo effects and improve patients' adherence in proposing biosimilars as treatment for autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease.

Effects of a probiotic treatment (Enterococcus faecalis) and open-label placebo on symptoms of allergic rhinitis: study protocol for a randomised controlled trial

INTRODUCTION

Several studies suggest that gut microbiota may play an important role in allergic diseases. The present trial aims to examine effects of the probiotic Enterococcus faecalis on symptoms of allergic rhinitis in patients. Effects of this probiotic on the immune system have been reported by several studies, but the majority of the previous trials were animal studies. In addition, it is well known that symptoms in allergic rhinitis are prone to exhibit high placebo responses. Moreover, recent studies report that even placebos without deception (open-label placebos) are highly effective in reducing symptoms of allergic rhinitis. Our study design combines both new approaches to assess effects on allergic symptoms in patients. The objective of this study is to compare the effects of a probiotic treatment (E. faecalis) with effects seen by open-label placebo, concealed placebo treatment and no treatment control.

METHODS AND ANALYSIS

A total of 120 patients with allergic rhinitis will be randomly assigned to one of four different groups: a double-blind probiotic/placebo group (groups 1 and 2), an open-label placebo group (group 3) and a no-treatment group (group 4) to control for spontaneous variation of symptoms. The primary outcome is the evaluation of allergic symptoms using the Combined Symptoms Medication Score. Furthermore, health-related quality of life is examined (Rhinitis Quality of Life Questionnaire). Secondary outcomes include a visual analogue scale on allergic burden and a second quality of life questionnaire. This report describes the study design of the randomised controlled trial.

ETHICS AND DISSEMINATION

The study design was approved by the ethical committee of the UKT Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany. The trial is registered at the German Clinical Trials Register (www.drks.de, DRKS00015804). The trial results will be published in peer-reviewed journals and at conferences.

TRIAL REGISTRATION NUMBER

German Clinical Trials Register (www.drks.de, DRKS00015804); Pre-results.

Clinical Features at Baseline Cannot Predict Symptom Response to Placebo in Patients With Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease characterized by ≥15 eosinophils per high-power field (eos/hpf) and esophageal dysfunction.¹ One confounder in the assessment of drug efficacy in clinical trials for EoE² and other gastrointestinal diseases^3,4 has been the symptomatic response to placebo. In placebo-controlled, randomized trials of EoE therapies, placebo response rates as high as 78% have been reported.² To mitigate placebo effect, a phase 2, randomized, double-blind, placebo-controlled trial of budesonide oral suspension (BOS) was designed with a single-blind, placebo run-in to attempt to screen out placebo responders before randomization.⁵ The aim of this post hoc analysis was to identify clinical factors associated with a symptom response during the placebo run-in.

Adverse Events and Nocebo Effects in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIMS

Nocebo effects, adverse outcomes occurring in patients receiving inert therapy, contribute to adverse event [AE] reporting in randomized controlled trials [RCTs]. High placebo AE rates may result in inaccurate estimation of treatment-related AEs. We estimate the pooled rate of AEs in patients randomized to placebo compared to active therapy in inflammatory bowel disease [IBD] RCTs.

METHODS

MEDLINE, EMBASE and CENTRAL were searched to March 1, 2017 for RCTs of conventional medical therapies for Crohn's disease [CD] or ulcerative colitis [UC]. Rates of AEs, serious AEs [SAEs], AE-related trial withdrawal, infections and worsening IBD were pooled using a random-effects model.

RESULTS

We included 124 CD [n = 26 042] and 71 UC RCTs [n = 16 798]. The pooled placebo AE rate was 70.6% (95% confidence interval [CI]: 65.3%, 75.4%) and 54.5% [47.8%, 61.1%] in CD and UC RCTs, respectively. There was no significant risk difference [RD] in AE, SAE or AE-related withdrawal rates between CD patients receiving placebo or active drug. A 1.6% [95% CI: 0.1%, 3.1%] increase in AE rates was observed among UC patients randomized to active therapy. Patients receiving active therapy had a higher risk of infection (RD 1.0% [95% CI: 0.4%, 1.7%] for CD, 2.9% [95% CI: 1.4%, 4.4%] for UC) although a lower risk of worsening CD (RD -3.2% [95% CI: -4.8%, -1.5%]) or UC (RD -3.7% [95% CI: -5.7%, -1.8%]).

CONCLUSIONS

AEs are commonly reported by patients randomized to either placebo or active treatment in IBD RCTs. Clinically relevant differences in AE, SAE and AE-related withdrawal were not observed.

A 5Ad Dietary Protocol for Functional Bowel Disorders

Functional bowel disorders (FBDs) affect around 20% of the population worldwide and are associated with reduced quality of life and high healthcare costs. Dietary therapies are frequently implemented to assist with symptom relief in these individuals, however, there are concerns regarding their complexity, restrictiveness, nutritional adequacy, and effectiveness. Thus, to overcome these limitations, a novel approach, the 5Ad Dietary Protocol, was designed and tested for its efficacy in reducing the severity of a range of gastrointestinal symptoms in 22 subjects with FBDs. The protocol was evaluated in a repeated measures MANOVA design (baseline week and intervention week). Measures of stool consistency and frequency were subtyped based on the subject baseline status. Significant improvements were seen in all abdominal symptom measures (p < 0.01). The effect was independent of body mass index (BMI), age, gender, physical activity level, and whether or not the subjects were formally diagnosed with irritable bowel syndrome (IBS) prior to participation. Stool consistency and frequency also improved in the respective contrasting subtypes. The 5Ad Dietary Protocol proved to be a promising universal approach for varying forms and severities of FBDs. The present study paves the way for future research encompassing a longer study duration and the exploration of underlying physiological mechanisms.

Effects of a Cod Protein Hydrolysate Supplement on Symptoms, Gut Integrity Markers and Fecal Fermentation in Patients with Irritable Bowel Syndrome

Peptides from fish may beneficially affect several metabolic outcomes, including gut health and inflammation. The effect of fish peptides in subjects with irritable bowel syndrome (IBS) has not previously been investigated, hence this study aimed to evaluate the effect of a cod protein hydrolysate (CPH) supplement on symptom severity, gut integrity markers and fecal fermentation in IBS-patients. A double-blind, randomized parallel-intervention with six weeks of supplementation with 2.5 g CPH (n = 13) or placebo (n = 15) was conducted. The outcomes were evaluated at baseline and the end of the study. The primary outcomes were symptom severity evaluated by the IBS severity scoring system (IBS-SSS) and quality of life. The secondary outcomes included gut integrity markers and pro-inflammatory cytokines in serum, fecal fermentation measured by concentration of short-chain fatty acids (SCFAs) and fecal calprotectin. The groups were comparable at baseline. The total IBS-SSS-scores were reduced in both the CPH-group (298 ± 69 to 236 ± 106, p = 0.081) and the placebo-group (295 ± 107 to 202 ± 103, p = 0.005), but the end of study-scores did not differ (p = 0.395). The concentrations of serum markers and SCFAs did not change for any of the groups. The baseline measures for the whole group showed that the total SCFA concentrations were inversely correlated with the total IBS-SSS-score (r = −0.527, p = 0.004). Our study showed that a low dose of CPH taken daily by IBS-patients for six weeks did not affect symptom severity, gut integrity markers or fecal fermentation when compared to the placebo group.

Diamine oxidase supplementation improves symptoms in patients with histamine intolerance

Histamine intolerance (HIT) is thought to be caused by a disproportionate amount of histamine in the body. The enzyme diamine oxidase (DAO) is considered for the gastrointestinal degradation of histamine. For this open-label interventional pilot study, we identified 28 patients with HIT. For 4 weeks, they were instructed to take DAO capsules before meals. Then, throughout a follow-up period, they were instructed not to take the DAO. We used a questionnaire that included 22 symptoms, which were divided into 4 categories, as well as a symptom severity score. All symptoms improved significantly during the oral supplementation of DAO. During the follow-up period, without DAO supplementation, the symptoms sum scores increased again. The symptom intensity score was reduced for all symptoms. We have demonstrated, a significant reduction of every HIT-related symptom and its intensity due to DAO oral supplements.

The ClinicalTrials.gov identifier (NCT number) is NCT03298568.

The placebo response in myasthenia gravis assessed by quantitative myasthenia gravis score: A meta-analysis

INTRODUCTION

This meta-analysis investigates the placebo response in generalized myasthenia gravis (MG) trials by means of Quantitative Myasthenia Gravis (QMG) scores.

METHODS

PubMed, Scopus, Web of Science, Cochrane Controlled Trial Register, and EMBASE were searched. QMG score, dropouts rate, adverse events (AEs), and AEs responsible for dropouts were examined, together with treatment moderators.

RESULTS

The magnitude of placebo response showed an effect size of 0.24, which was significantly lower than 0.67 of the drug response (P = 0.019). Furthermore, the forest plot revealed that, overall, active treatments showed a significantly higher impact on QMG scores than placebos.

CONCLUSIONS

Placebo and drug responses in MG trials are small and moderate, respectively. The lack of MG trials with a pure placebo arm or a no-treatment control arm made it impossible to disentangle improvements due to the placebo psychological effect from other effects such as natural history and/or regression to the mean. Muscle Nerve 59:671-678, 2019.

Can a Brief Relaxation Exercise Modulate Placebo or Nocebo Effects in a Visceral Pain Model?

Translational research aiming to elucidate mediators and moderators of placebo and nocebo effects is highly relevant. This experimental study tested effects of a brief progressive muscle relaxation (PMR) exercise, designed to alter psychobiological stress parameters, on the magnitude of placebo and nocebo effects in a standardized psychosocial treatment context. In 120 healthy volunteers (60 men, 60 women), pain expectation, pain intensity, and pain unpleasantness in response to individually-calibrated rectal distensions were measured with visual analog scales during a baseline. Participants were then randomized to exercise PMR (relaxation group: N = 60) or a simple task (control group: N = 60), prior to receiving positive (placebo), negative (nocebo) or neutral suggestions regarding an intravenous administration that was in reality saline in all groups. Identical distensions were repeated (test). State anxiety, salivary cortisol, heart rate, and blood pressure were assessed repeatedly. Data were analyzed using analysis of covariance, planned Bonferroni-corrected group comparisons, as well as exploratory correlational and mediation analyses. Treatment suggestions induced group-specific changes in pain expectation, with significantly reduced expectation in placebo and increased expectation in nocebo groups. PMR had no discernable effect on pain expectation, state anxiety or cortisol, but led to significantly lower heart rate and systolic blood pressure. Relaxation significantly interacted with positive treatment suggestions, which only induced placebo analgesia in relaxed participants. No effects of negative suggestions were found in planned group comparisons, irrespective of relaxation. Exploratory correlation and mediation analyses revealed that pain expectation was a mediator to explain the association between treatment suggestions and pain-related outcomes. Clearly, visceral pain modulation is complex and involves many cognitive, emotional, and possibly neurobiological factors that remain to be fully understood. Our findings suggest that a brief relaxation exercise may facilitate the induction of placebo analgesia by positive when compared to neutral treatment suggestions. They underscore the contribution of relaxation and stress as psychobiological states within the psychosocial treatment context-factors which clearly deserve more attention in translational studies aiming to maximize positive expectancy effects in clinical settings.

Does Sex/Gender Play a Role in Placebo and Nocebo Effects? Conflicting Evidence From Clinical Trials and Experimental Studies

Sex has been speculated to be a predictor of the placebo and nocebo effect for many years, but whether this holds true or not has rarely been investigated. We utilized a placebo literature database on various aspects of the genuine placebo/nocebo response. In 2015, we had extracted 75 systematic reviews, meta-analyses, and meta-regressions performed in major medical areas (neurology, psychiatry, internal medicine). These meta-analyses were screened for whether sex/gender differences had been noted to contribute to the placebo/nocebo effect: in only 3 such analyses female sex was associated with a higher placebo effect, indicating poor evidence for a contribution of sex to it in RCTs. This was updated with another set of meta-analyses for the current review, but did not change the overall conclusion. The same holds true for 18 meta-analyses investigating adverse event (nocebo) reporting in RCT in the placebo arm of trials. We also screened our database for papers referring to sex/gender and the placebo effect in experimental studies, and identified 28 papers reporting 29 experiments. Their results can be summarized as follows: (a) Despite higher sensitivity of pain in females, placebo analgesia is easier to elicit in males; (b) It appears that conditioning is effective specifically eliciting nocebo effects; (c) Conditioning works specifically well to elicit placebo and nocebo effects in females and with nausea; (d) Verbal suggestions are not sufficient to induce analgesia in women, but work in men. These results will be discussed with respect to the question why nausea and pain may be prone to be responsive to sex/gender differences, while other symptoms are less. Lastly, we will discuss the apparent discrepancy between RCT with low relevance of sex, and higher relevance of sex in specific experimental settings. We argue that the placebo response is predominantly the result of a conditioning (learning) response in females, while in males it predominantly may be generated via (verbal) manipulating of expectancies. In RCT therefore, the net outcome of the intervention may be the same despite different mechanisms generating the placebo effect between the sexes, while in experimental work when both pathways are separated and explicitly explored, such differences may surface.

Time to treatment response of a magnesium- and sulphate-rich natural mineral water in functional constipation

OBJECTIVES

First-line recommendations for the management of functional constipation include nutritional-hygienic measures. We previously showed that a natural mineral water rich in sulphates and magnesium (Hépar) is efficient in the treatment of functional constipation. The aim of this study was to consolidate those first results and determine a precise time to respond to Hépar.

METHODS

This multicenter, randomized, double-blind, controlled study of the effect of Hépar on stool consistency and frequency in functional constipation included 226 outpatients. After washout, patients used 1.5 L of water daily, including 1 L of Hépar or of low-mineral water, during 14 d. In addition to a daily reporting of stool consistency by the patient, an expert investigator blindly analyzed stool consistency (Bristol stool scale) based on photographs taken by the patient.

RESULTS

The primary endpoint was met. Treatment response was more frequent in the Hépar arm than in the control group at day 14 (50% versus 29%, respectively; P = 0.001). Mean time to treatment response was shorter in the Hépar group (6.4 d) than in the control arm (7.3 d; P = 0.013). Concomitant stool scoring was available for 60% of the patients. Scores given to 79% of the stools were similar between the patient and the expert (differences ≤1). Safety analyses showed excellent results.

CONCLUSION

This study confirms the efficacy and safety of Hépar in the treatment of functional constipation and shows that it is associated with a response within 7 d. Hépar could be a safe response to the current absence of first-line medication in the treatment of functional constipation.

The gut-brain axis in health neuroscience: implications for functional gastrointestinal disorders and appetite regulation

Over the past few years, scientific interest in the gut-brain axis (i.e., the bidirectional communication system between the gastrointestinal tract and the brain) has exploded, mostly due to the identification of the gut microbiota as a novel key player in this communication. However, important progress has also been made in other aspects of gut-brain axis research, which has been relatively underemphasized in the review literature. Therefore, in this review, we provide a comprehensive, although not exhaustive, overview of recent research on the functional neuroanatomy of the gut-brain axis and its relevance toward the multidisciplinary field of health neuroscience, excluding studies on the role of the gut microbiota. More specifically, we first focus on irritable bowel syndrome, after which we outline recent findings on the role of the gut-brain axis in appetite and feeding regulation, primarily focusing on the impact of subliminal nutrient-related gut-brain signals. We conclude by providing future perspectives to facilitate translation of the findings from gut-brain axis neuroscientific research to clinical applications in these domains.

Efficacy of the gluten free diet in the management of functional gastrointestinal disorders: a systematic review on behalf of the Italian Society of Paediatrics

BACKGROUND

Functional gastrointestinal disorders (FGIDs) are characterized by chronic/recurrent gastrointestinal symptoms not related to organic disorders. Due to the limited treatment options and to the perception of subjects with FGIDs suffering from a food intolerance, in recent years there has been an increase in the self-prescription of elimination diets, especially gluten free diet (GFD), for the treatment of these disorders. For this reason, we decided to perform this systematic review with the aim to evaluate the available evidence on the effects of a GFD on gastrointestinal symptoms, in subjects with FGIDs.

METHODS

Cochrane Library and MEDLINE (via PubMed) databases were searched, from inception to March 2018, using the MeSH terms "functional gastrointestinal disorder OR irritable bowel syndrome AND gluten". We included all the clinical trials published in English and evaluating the effects of a GFD in subjects with FGIDs diagnosed according to the Rome II, III, and IV criteria.

RESULTS

Eleven trials were eligible (3 prospective trials, 8 single or double-blind placebo-controlled trials), with 10/11 trials including adult subjects with irritable bowel syndrome (IBS) or FGIDs. Most of the prospective studies found an effect of GFD on gastrointestinal symptoms control. Nevertheless, 1 trial failed to find an association between gluten and GI symptoms when FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) content was simultaneously reduced in the diet, and 2 trials reported a worsening of symptoms during placebo administration. The results of the different trials are difficult to compare due to discrepancies in the study protocols regarding the amount and type of gluten administered, the duration of the gluten challenge, the type of placebo used, and the duration of the challenge itself.

CONCLUSIONS

According to our results, gluten may contribute to the occurrence of gastrointestinal symptoms in patients with FGIDs, particularly in those with IBS. Nevertheless, the results of the currently available trials are difficult to compare due to the lack of standardization in the study designs. For this reason, it is still not possible to recommend the use of the GFD in the routine management of FGIDs.

Inhaled Corticosteroids and Placebo Treatment Effects in Adult Patients With Cough: A Systematic Review and Meta-analysis

PURPOSE

Inhaled corticosteroids (ICSs) are often considered an empirical therapy in the management of patients with cough. However, ICS responsiveness is difficult to interpret in daily clinical practice, as the improvements may include placebo effects or self-remission. We aimed to evaluate ICS and placebo treatment effects in adult patients with cough.

METHODS

Electronic databases were searched for studies published until June 2018, without language restriction. Randomized controlled trials reporting the effects of ICSs compared with placebo in adult patients with cough were included. Random effects meta-analyses were conducted to estimate the treatment effects. Therapeutic gain was calculated by subtracting the percentage change from baseline in the cough score in the ICS treatment group from that in the placebo treatment group.

RESULTS

A total of 9 studies were identified and 8 studies measuring cough severity outcomes were included for meta-analyses. Therapeutic gain from ICSs ranged from -5.0% to +94.6% across the studies included; however, it did not exceed +22%, except for an outlier reporting very high therapeutic gains (+45.6% to +94.6%, depending on outcomes). Overall ICS treatment effects in cough severity outcomes were small-to-moderate (standardized mean difference [SMD], -0.38; 95% confidence interval [CI], -0.54, -0.23), which were comparable between subacute and chronic coughs. However, pooled placebo treatment effects were very large in subacute cough (SMD, -2.58; 95% CI, -3.03, -2.1), and modest but significant in chronic cough (SMD, -0.46; 95% CI, -0.72, -0.21).

CONCLUSIONS

Overall therapeutic gain from ICSs is small-to-moderate. However, placebo treatment effects of ICS are large in subacute cough, and modest but still significant in chronic cough. These findings indicate the need for careful interpretation of ICS responsiveness in the management of cough patients in the clinic, and also for rigorous patient selection to identify ICS-responders.

Placebo Effects in Psychotherapy: A Framework

The issue of placebo response and the extent of its effect on psychotherapy is complex for two specific reasons: i) Current standards for drug trials, e.g., true placebo interventions, double-blinding, cannot be applied to most psychotherapy techniques, and ii) some of the "nonspecific effects" in drug therapy have very specific effects in psychotherapy, such as the frequency and intensity of patient-therapist interaction. In addition, different psychotherapy approaches share many such specific effects (the "dodo bird verdict") and lack specificity with respect to therapy outcome. Here, we discuss the placebo effect in psychotherapy under four aspects: a) nonspecific factors shared with drug therapy (context factors); b) nonspecific factors shared among all psychotherapy traditions (common factors); c) specific placebo-controlled options with different psychotherapy modalities; and d) nonspecific control options for the specific placebo effect in psychotherapy. The resulting framework proposes that the exploration and enumeration of context factors, common factors, and specific factors contributes to the placebo effects in psychotherapy.

Placebos and the Placebo Effect in Drug Trials

In this review, we explored different ways of controlling the placebo effects in clinical trials and described various factors that may increase/decrease the placebo effect in randomized placebo-controlled trials. These factors can be subdivided into four groups, and while not all factors are effective in every study and under all clinical conditions, they show on the whole that - even under the ideal condition of drug therapy, where blinded placebo provision is much easier and warranted than in, e.g., psychotherapy - many factors need to be controlled to ascertain that the goal of the clinical trials, fair assessment of superiority of the drug over placebo in placebo-controlled trials and fair assessment of non-inferiority of the drug compared to another drug in comparator trials, is reached. Ignorance towards the placebo effect, which was common in the past, is no longer acceptable; instead, it should be the goal of all therapeutic trials to minimize the placebo effect in clinical trials, while utilizing and maximizing it in clinical routine.

Placebo Effect on the Health-related Quality of Life of Inflammatory Bowel Disease Patients: A Systematic Review With Meta-analysis

BACKGROUND AND AIMS

Placebo effect in health-related quality of life [HRQoL] of inflammatory bowel disease [IBD] patients has been poorly characterised. This systematic review and meta-analysis aimed to assess: i] mean improvements in IBDQ [Inflammatory Bowel Disease Questionnaire] and SF-36 [36-Item Short Form Health Survey] scores among placebo-treated IBD patients; and ii] the proportion of placebo-treated patients achieving IBDQ-defined response and remission and correspondent odds ratios [OR].

METHODS

Literature search was performed using four databases. Mean differences and ORs were computed using the random-effects model. Univariate and multivariate regressions were performed to evaluate the weight of different factors on the placebo effect.

RESULTS

From the 328 identified records 26 were included in the study, comprising 2842 placebo-treated IBD patients. Pooled mean differences on IBDQ following placebo administration were above the clinically meaningful improvement [≥16 points] in ulcerative colitis [UC] patients during the induction regimen (17.67; 95% confidence interval [CI]: 12.90, 22.44) and during maintenance in both Crohn's disease [CD] [27.60; 95% CI: 14.29, 40.91] and UC patients [27.50; 95% CI: 18.73, 36.27]. The treatment regimen was the only significant variable in multivariate analysis, with lower placebo-related IBDQ improvements during induction. Maintenance trials' inclusion criteria were also relevant. The proportions of placebo-treated patients achieving IBDQ-defined response and remission were 0.42 [95% CI: 0.49, 0.56] and 0.31 [95% CI: 0.28, 0.34], respectively, with 0.49 and 0.40 the ORs for response and remission. Significant improvements were also observed on SF-36 score.

CONCLUSIONS

Herein we prove that placebo effect on HRQoL is meaningful, providing insights about implications for clinical trials' design and interpretation and for IBD management.

Heterogeneity in Clinical, Endoscopic, and Histologic Outcome Measures and Placebo Response Rates in Clinical Trials of Eosinophilic Esophagitis: A Systematic Review

BACKGROUND & AIMS

Agents are being developed for treatment of eosinophilic esophagitis (EoE). However, it is not clear what outcome measures would best determine the efficacy and safety of these agents in clinical trials. We performed a systematic review of outcomes used in randomized placebo-controlled trials of EoE and we estimate the placebo response and rates of remission.

METHODS

We searched MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, and the EU Clinical Trials Register from inception through February 20, 2018 for randomized controlled trials of pharmacologic therapies for EoE. Efficacy outcome definitions, measurement tools, and the proportion of patients responding to placebo were collected and stratified by based on histologic, endoscopic, and patient-reported outcomes.

RESULTS

We analyzed data from 22 placebo-controlled trials, comprising 1112 patients with EoE. Ten additional active registered trials were identified. Most published trials evaluated topical corticosteroid therapy (13/22, 59.1%). Histologic outcomes measuring eosinophil density and patient-reported outcomes were reported in 21/22 published trials (95.5%). No consistently applied definitions of histologic or patient-reported response or remission were identified. Endoscopic outcomes were described in 60% (12/20) of published trials. The EoE Endoscopic Reference Score is the most commonly applied tool for describing changes in endoscopic appearance. The median histologic response to placebo was 3.7% (range, 0%-31.6%) and the median rate of remission in patients given placebo was 0.0% (range, 0%-11.0%). The median patient-reported response to placebo was 14.4% (range, 8.6%-77.8%) and rate of remission in patients given placebo was 26.2% (range, 13.2%-35.7%).

CONCLUSIONS

In a systematic review of the literature, we found that no standardized definitions of histologic, endoscopic, or patient-reported outcomes are used to determine whether pharmacologic agents produce a response or remission in patients with EoE. A core outcome set is needed to reduce heterogeneity in outcome reporting and facilitate trial interpretation and comparison of results from trials.

Behavioural and neural responses to aversive visceral stimuli in women with primary dysmenorrhoea

BACKGROUND

Chronic pelvic pain, in particular dysmenorrhoea, is a significant yet unresolved healthcare problem in gynaecology. As interoceptive sensitivity and underlying neural mechanisms remain incompletely understood, this functional magnetic resonance imaging (fMRI) study assessed behavioural and neural responses to visceral stimuli in primary dysmenorrhoea (PMD).

METHODS

Women with PMD (N = 19) without psychological comorbidity and healthy women (N = 20) were compared with respect to visceral sensory and pain thresholds, and to neural responses to individually calibrated mildly painful and painful rectal distensions implemented during scanning. Trial-by-trial ratings of perceived intensity were accomplished with visual analogue scales (VAS).

RESULTS

Although women with dysmenorrhoea reported significantly higher chronic pain intensity and pain interference with daily life activities (p < 0.01, assessed with the West Haven-Yale Multidimensional Pain Inventory), there were no differences between groups in visceral sensitivity and mean trial-by-trial VAS ratings were virtually identical. Analysis of neural responses revealed activation in brain regions previously shown to be involved in the processing of visceral stimuli with differences between painful and mildly painful stimulation, but no group differences were found even when using a liberal statistical threshold.

CONCLUSIONS

Dysmenorrhoea patients show unaltered perceptual and neural responses to experimental interoceptive stimuli. Despite limited sample size, these negative results argue against a generalized sensitization towards interoceptive stimuli in patients without psychological comorbidities. Future studies should clarify the role of psychosocial factors in central sensitization using more pain region-specific models in larger and clinically more heterogeneous samples.

SIGNIFICANCE

Despite higher chronic pain and pain interference with daily life activities, women with primary dysmenorrhoea do not differ from healthy women with respect to visceral sensitivity or neural processing of aversive interoceptive stimuli induced by rectal distensions. Generalized sensitization may be present only in subgroups with pronounced psychosocial or psychiatric disturbances.

Placebo Effect: Theory, Mechanisms and Teleological Roots

Why pain can be relieved with placebos is heavily debated. The term "placebo effect," implies that the placebo treatment induces pain relief which is imprecise because it is the mental cueing to the context of treatment and not the placebo itself that can reduce pain. This essay reverts to fundamentals of perception that have been used to explain how context generates predictions that can in turn effect the process of processing, organizing and interpreting of sensory inputs received from the periphery. We reinterpret placebo effect as a neurobiological phenomenon that occurs through the process of reward and aversive learning. The brain uses learnt information to generate predictions. The perceptual processes adjust the experience of pain to fit with the predictions generated from prior information. Placebo effect is thus understandably a result of the expectations and mental states that result from engaging in the process of treatment. These processes have teleological roots in ancient medicine and are the context that produces these responses is transforming with the evolution of modern medicine. Thus, when placebo effect is observed, the potent agent that induces pain reduction is not the placebo itself, but the mental cueing to the context of taking treatment.

Improvement in Gastrointestinal Symptoms After Cognitive Behavior Therapy for Refractory Irritable Bowel Syndrome

BACKGROUND & AIMS

There is an urgent need for safe treatments for irritable bowel syndrome (IBS) that relieve treatment-refractory symptoms and their societal and economic burden. Cognitive behavior therapy (CBT) is an effective treatment that has not been broadly adopted into routine clinical practice. We performed a randomized controlled trial to assess clinical responses to home-based CBT compared with clinic-based CBT and patient education.

METHODS

We performed a prospective study of 436 patients with IBS, based on Rome III criteria, at 2 tertiary centers from August 23, 2010, through October 21, 2016. Subjects (41.4 ± 14.8 years old; 80% women) were randomly assigned to groups that received the following: standard-CBT (S-CBT, n = 146, comprising 10 weekly, 60-minute sessions that emphasized the provision of information about brain-gut interactions; self-monitoring of symptoms, their triggers, and consequences; muscle relaxation; worry control; flexible problem solving; and relapse prevention training), or 4 sessions of primarily home-based CBT requiring minimal therapist contact (MC-CBT, n = 145), in which patients received home-study materials covering the same procedures as S-CBT), or 4 sessions of IBS education (EDU, n = 145) that provided support and information about IBS and the role of lifestyle factors such as stress, diet, and exercise. The primary outcome was global improvement of IBS symptoms, based on the IBS-version of the Clinical Global Impressions-Improvement Scale. Ratings were performed by patients and board-certified gastroenterologists blinded to treatment allocation. Efficacy data were collected 2 weeks, 3 months, and 6 months after treatment completion.

RESULTS

A higher proportion of patients receiving MC-CBT reported moderate to substantial improvement in gastrointestinal symptoms 2 weeks after treatment (61.0% based on ratings by patients and 55.7% based on ratings by gastroenterologists) than those receiving EDU (43.5% based on ratings patients and 40.4% based on ratings by gastroenterologists) (P < .05). Gastrointestinal symptom improvement, rated by gastroenterologists, 6 months after the end of treatment also differed significantly between the MC-CBT (58.4%) and EDU groups (44.8%) (P = .05). Formal equivalence testing applied across multiple contrasts indicated that MC-CBT is at least as effective as S-CBT in improving IBS symptoms. Patients tended to be more satisfied with CBT vs EDU (P < .05) based on immediate posttreatment responses to the Client Satisfaction Questionnaire. Symptom improvement was not significantly related to concomitant use of medications.

CONCLUSIONS

In a randomized controlled trial, we found that a primarily home-based version of CBT produced significant and sustained gastrointestinal symptom improvement for patients with IBS compared with education. Clinicaltrials.gov no.: NCT00738920.

Fat label compared with fat content: gastrointestinal symptoms and brain activity in functional dyspepsia patients and healthy controls

Background

High-fat meals are associated with dyspeptic symptoms in functional dyspepsia (FD) patients. It is still unclear how fat is processed, or how FD symptoms and neuronal activities are modulated by psychological factors.

Objective

We investigated brain activity by functional magnetic resonance imaging (fMRI) after the ingestion of high- and low-fat foods with correct/incorrect fat information.

Design

We compared 12 FD patients and 14 healthy controls (HCs). We recorded resting-state fMRI on four different days before and after ingestion of four yogurts (200 mL, 10% or 0.1% fat, "low fat" or "high fat" label).

Results

FD patients showed more pronounced dyspeptic symptoms than did HCs, and symptoms were relieved less after consuming high fat-labeled yogurt than low fat-labeled yogurt, irrespective of the actual fat content. This is indicative of either a placebo effect of low-fat information or a nocebo effect of high-fat information on symptom expression. FD patients showed greater activity than did HCs in occipital areas before and after ingestion regardless of fat content and label, as well as greater activity in the middle frontal gyrus before ingestion. In addition, functional connectivity (FC) from the insula to the occipital cortex (I-O) increased after high fat ingestion and decreased after low fat ingestion in FD patients. FC from the insula to the precuneus (I-P) was higher in FD patients than in HCs after ingestion of low fat-labeled yogurt. In FD patients, I-O FC negatively correlated with nausea and I-P FC with FD symptom intensity, food craving, and depression.

Conclusions

Our results endorse the importance of psychological perception of food on the incidence of dyspeptic symptoms and on the altered brain activities. These findings show the importance of cognitive components in perceptions of fat, food craving, depression, and brain functions in pathophysiologic mechanisms of FD. This trial was registered at clinicaltrials.gov as NCT02618070.

The Management of Paediatric Functional Abdominal Pain Disorders: Latest Evidence

Recurrent abdominal pain (RAP) is one of the most common health complaints in both children and adults. Although RAP is considered a functional disorder rather than an organic disease, affected children and their families can still experience anxiety and concerns that can interfere with school, sports, and regular daily activities and lead to frequent attendances at pediatric emergency departments or pediatric gastroenterology clinics. Our review shows experts do not agree on a universally proven management that will work on every child presenting with functional abdominal pain (FAP). Treatment strategies include both non-pharmacological and pharmacological options. Non-pharmacological treatments are usually very well accepted by both children and their parents and are free from medication side effects. Nevertheless, they may be as effective as the pharmacological interventions; therefore, according to many experts and based on the majority of current evidence, a non-pharmacological approach should be the first intervention attempt in children with RAP. In particular, the importance of the bio-psychosocial approach is highlighted, as a majority of children will improve with counselling and reassurance that no serious organic pathologies are suspected, especially when the physician establishes a trustful relationship with both the child and their family. Placebo and pharmacological interventions could be attempted when the bio-psychosocial approach is not applicable or not efficacious. In some difficult cases, finding an effective treatment for FAP can be a challenge, and a number of strategies may need to be tried before symptoms are controlled. In these cases, a multidisciplinary team, comprising a pediatric gastroenterologist, dietician, psychologist, and psychotherapist, is likely to be successful.

Effects of acute psychological stress on placebo and nocebo responses in a clinically relevant model of visceroception

There is evidence to suggest a role of emotions in placebo and nocebo effects, but whether acute psychological stress changes the magnitude of placebo or nocebo responses has not been tested. In a clinically relevant model of visceroception, we assessed effects of acute psychological stress on changes in urgency and pain in response to positive or negative treatment suggestions. In 120 healthy volunteers, perceived urge-to-defecate and pain in response to individually calibrated rectal distensions were measured with visual analogue scales during a BASELINE. Participants then underwent the Trier Social Stress Test (N = 60) or a simple cognitive task (control, N = 60) and were randomized to positive (placebo), negative (nocebo), or neutral treatment information regarding intravenous administration of saline. The series of distensions was repeated, and changes in visual analogue scales from BASELINE to TEST were compared between groups using analysis of covariance and planned post hoc tests. Treatment information emerged as a main factor (P <0.001), supporting treatment information effects for both urgency and pain. Effects for urgency were modulated by stress (interaction effect: P <0.05): Positive information reduced urgency (P = 0.025), while negative information increased urgency (P = 0.026) only in stressed groups. For pain, effects of stress emerged for nocebo responses, which were only evident in stressed groups (P = 0.009). This is the first experimental study supporting effects of acute psychological stress on placebo and nocebo responses in visceroception. Results call for mechanistic as well as patient studies to assess how psychological stress shapes patients' treatment expectations and thereby affects health outcomes.

Functional abdominal pain disorders in children

Chronic abdominal pain is a common problem in pediatric practice. The majority of cases fulfill the Rome IV criteria for functional abdominal pain disorders (FAPDs). At times, these disorders may lead to rather serious repercussions. Area covered: We have attempted to cover current knowledge on epidemiology, pathophysiology, risk factors related to pathophysiology, clinical evaluation and management of children with FAPDs. Expert commentary: FAPDs are a worldwide problem with a pooled prevalence of 13.5%. There are a number of predisposing factors and pathophysiological mechanisms including stressful events, child maltreatment, visceral hypersensitivity, altered gastrointestinal motility and change in intestinal microbiota. It is possible that the environmental risk factors intricately interact with genes through epigenetic mechanisms to contribute to the pathophysiology. The diagnosis mainly depends on clinical evaluation. Commonly used pharmacological interventions do not play a major role in relieving symptoms. Centrally directed, nonpharmacological interventions such as hypnotherapy and cognitive behavioral therapy have shown both short and long term efficacy in relieving pain in children with FAPDs. However, these interventions are time consuming and need specially trained staff and therefore, not currently available at grass root level. Clinicians and researchers should join hands in searching for more pragmatic and effective therapeutic modalities to improve overall care of children with FAPDs.

Nocebo Effects and Experimental Models in Visceral Pain

Despite its clinical relevance and the potential to extend insights into the processing and modulation of pain derived from investigations of placebo phenomena, the nocebo effect has received comparably little attention over the past decades. Research from experimental and clinical studies is only beginning to unravel the behavioral, functional, and psychoneurobiological mechanisms underlying the nocebo effect. Herein, we summarize current evidence regarding nocebo effects in the field of pain, with a particular emphasis on visceral pain. We provide an overview over behavioral and neuroimaging findings on the impact of expectations and learning and propose promising future directions to help fostering the transition of experimental research from bench to bedside.

Irritable Bowel Syndrome: Patient-Provider Interaction and Patient Education

The Patient-Provider (P-P) relationship is the foundation of medical practice. The quality of this relationship is essential, particularly for the management of chronic illness such as Irritable Bowel Syndrome (IBS), since it correlates with disease improvement. A significant aspect of fostering the P-P relationship is providing effective patient-centered education about IBS. An effective education empowers the patients to achieve the main therapeutic goals: to reduce symptoms and improve quality of life. Method: A literature search of PubMed was conducted using the terms “Irritable Bowel syndrome”, “Patient Physician Relationship”, “Patient Provider Relationship”, and “Patient Physician interaction”. Preference was given to articles with a clearly defined methodology and those with control groups if applicable/appropriate. This article provides a review of the literature on Patient-Provider interaction and patient education as it relates to IBS and provides practical recommendations on how to optimize this important relationship.

Factors Associated With Efficacy of Percutaneous Tibial Nerve Stimulation for Fecal Incontinence, Based on Post-Hoc Analysis of Data From a Randomized Trial

BACKGROUND & AIMS

A recent randomized, multi-center, phase 3 trial, performed in the United Kingdom (Control of Fecal Incontinence using Distal Neuromodulation Trial), demonstrated no significant clinical benefit of percutaneous tibial nerve stimulation (PTNS) compared to sham stimulation in patients with fecal incontinence (FI). However, this study did not analyze predictors of response. We used data from this trial to identify factors that predict the efficacy of PTNS in adults with FI.

METHODS

The study population comprised 205 patients from the CONtrol of Fecal Incontinence using Distal NeuromodulaTion Trial. The primary outcome was a binary indicator of success (≥50% reduction in weekly FI episodes after 12 weeks of treatment) or failure, as per the original trial characteristics including baseline FI symptom type, defecatory urgency, and co-existent symptoms of baseline liquid stool consistency and obstructive defecation (OD) were defined a priori. Univariable and multivariable analyses were performed to explore these factors as predictors of response to PTNS and sham.

RESULTS

In both univariable and multivariable analysis, the presence of OD symptoms negatively predicted outcome in patients who received PTNS (OR, 0.38; 95% CI, 0.16-0.91; P = .029), and positively predicted sham response (OR, 3.45; 95% CI, 1.31-9.21; P = .012). No other tested variable affected outcome. Re-analysis of the primary outcome excluding patients with OD symptoms (n = 112) resulted in a significant clinical effect of PTNS compared to sham (48.9% vs 18.2% response, P = .002; multivariable OR, 4.71; 95% CI, 1.71-12.93; P = .003).

CONCLUSIONS

Concomitant OD symptoms negatively affected the clinical outcome of PTNS vs sham in a major randomized controlled trial. Future appropriately designed studies could further explore this observation with potential for future stratified patient selection.

Novel designs and paradigms to study the placebo response in gastroenterology

The investigation of the placebo and the nocebo effect and their mechanisms has a rather short history of less than 20 years, especially in gastroenterology, and only the last 5 years have resulted in substantial improvement of understanding. Placebo refers to symptom improvement following a treatment, nocebo to the opposite, symptom worsening. Among the factors driving this progress are traditional psychological models derived from learning (conditioning) theory bridging into clinical science, new animal models to investigate the pharmacology of placebo analgesia, and novel study designs to overcome limitations of traditional randomized and placebo-controlled study designs in drug testing. These are explored here for their implementation and application in gastroenterology, with a focus on visceral pain and nausea.

A Diet Low in FODMAPs Reduces Symptoms in Patients With Irritable Bowel Syndrome and A Probiotic Restores Bifidobacterium Species: A Randomized Controlled Trial

BACKGROUND & AIMS

Dietary restriction of fermentable carbohydrates (a low FODMAP diet) has been reported to reduce symptoms in some patients with irritable bowel syndrome (IBS). We performed a randomized, placebo-controlled study to determine its effects on symptoms and the fecal microbiota in patients with IBS.

METHODS

We performed a 2×2 factorial trial of 104 patients with IBS (18-65 years old), based on the Rome III criteria, at 2 hospitals in the United Kingdom. Patients were randomly assigned (blinded) to groups given counselling to follow a sham diet or diet low in FODMAPs for 4 weeks, along with a placebo or multistrain probiotic formulation, resulting in 4 groups (27 receiving sham diet/placebo, 26 receiving sham diet/probiotic, 24 receiving low FODMAP diet /placebo, and 27 receiving low FODMAP diet/probiotic). The sham diet restricted a similar number of staple and non-staple foods as the low FODMAP diet; the diets had similar degrees of difficulty to follow. Dietary counselling was given to patients in all groups and data on foods eaten and compliance were collected. The incidence and severity of 15 gastrointestinal symptoms and overall symptoms were measured daily for 7 days before the study period; along with stool frequency and consistency. At baseline, global and individual symptoms were measured, along with generic and disease-specific health-related quality of life, using standard scoring systems. All data were collected again at 4 weeks, and patients answered questions about adequate symptom relief. Fecal samples were collected at baseline and after 4 weeks and analyzed by quantitative PCR and 16S rRNA sequencing. The co-primary endpoints were adequate relief of symptoms and stool Bifidobacterium species abundance at 4 weeks.

RESULTS

There was no significant interaction between the interventions in adequate relief of symptoms (P = .52) or Bifidobacterium species (P = .68). In the intention-to-treat analysis, a higher proportion of patients in the low FODMAP diet had adequate symptom relief (57%) than in the sham diet group (38%), although the difference was not statistically significant (P = .051). In the per-protocol analysis, a significantly higher proportion of patients on the low FODMAP diet had adequate symptom relief (61%) than in the sham diet group (39%) (P = .042). Total mean IBS-Severity Scoring System score was significantly lower for patients on the low FODMAP diet (173 ± 95) than the sham diet (224 ± 89) (P = .001), but not different between those given probiotic (207 ± 98) or placebo (192 ± 93) (P = .721) Abundance of Bifidobacterium species was lower in fecal samples from patients on the low FODMAP diet (8.8 rRNA genes/g) than patients on the sham diet (9.2 rRNA genes/g) (P = .008), but higher in patients given probiotic (9.1 rRNA genes/g) than patients given placebo (8.8 rRNA genes/g) (P = .019). There was no effect of the low FODMAP diet on microbiota diversity in fecal samples.

CONCLUSIONS

In a placebo-controlled study of patients with IBS, a low FODMAP diet associates with adequate symptom relief and significantly reduced symptom scores compared with placebo. It is not clear whether changes resulted from collective FODMAP restriction or removal of a single component, such as lactose. Co-administration of the multistrain probiotic increased numbers of Bifidobacterium species, compared with placebo, and might be given to restore these bacteria to patients on a low FODMAP diet. Trial registration no: ISRCTN02275221.

Efficacy of individualised diets in patients with irritable bowel syndrome: a randomised controlled trial

Background

Patients 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.

Methods

This 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.

Results

The 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.

Conclusions

Elimination diets guided by leucocyte activation tests reduced symptoms. These findings could lead to insights into the pathophysiology of IBS.

Trial registration number

NCT02186743.