Society: AGA

Background: Irritable bowel syndrome (IBS) is a common disorder with complex pathophysiological mechanisms. Prior studies suggest that 25-50% of patients with diarrhea-predominant IBS (IBS-D) have evidence of bile acid (BA) diarrhea (BAD). Studies of candidate genes involved in the BA pathway have identified single nucleotide variants (SNVs) in the synthesis of farnesoid X receptor (NR1H4, MALRD1/DIET1), proteins involved in hepatic re-uptake of BA (KLB, FGFR4), the rate-limiting enzyme of BA synthesis (CYP7A1), and BA receptors (GPBAR1/TGR5) that may be implicated in the pathophysiology of IBS-D and BAD. Aim: To explore the burden of allelic variants among known SNVs across these genes in IBS-D. Methods: Design: Case-control analysis of the genetic differences between those with diagnosis of IBS-D compared to age- and sex-matched controls. Genomic data were provided by the Mayo Clinic Tapestry Study for the target genes listed above along with links exomic database which was linked to the electronic medical record (EMR). Cases of IBS-D were defined according to ICD-10 code, and controls were those without documentation of the same ICD-10 diagnosis. SNVs with either low quality, read depth, or probability of a functional impact (e.g. synonymous and non-splice site intronic variants) were disregarded. The total burden of non-reference alleles between IBS-D and control patients was compared using ANOVA with α=0.05. Results: After data cleaning, our final sample included 526 patients with IBS-D and 2,950 controls. The mean (SD) age of the entire sample was 53.1 (15.8) years, and majority (78.9%) were female (Table 1). Three thousand and eighteen (95.5%) participants self-identified as White. Only ethnicity was statistically significantly different between the groups, with 4.6% and 9.4% identifying as Hispanic or Latino in the IBS-D and control groups, respectively. The summary of the genetic findings is shown in Table 2. Participants in the IBS-D group had, on average, a significantly greater genetic burden of homozygous alternate alleles in MALRD1 compared to controls (p=0.006). There was a greater proportion of heterozygote genotypes for key SNVs in CYP7A1 in controls compared to those with IBS-D. Other SNVs in candidate genes did not demonstrate a statistically significant difference in frequency of alternate alleles between IBS-D and controls. Conclusions: MALRD1 (previously DIET1), a gene that codes for an intestinal protein involved in enterohepatic circulation by regulating FGF-19 and CYP7A1 (BA synthesis), may contribute to pathophysiological mechanisms in IBS-D. Further studies are needed to explore specific genetic variants and their functional impact in MALRD1 and CYP7A1 in IBS-D that may elucidate disease mechanisms and potential therapeutic targets, such as with FGF-19 analogs or FXR agonists.

<b>Table 1. Demographics of Tapestry participants by diagnosis of diarrhea-predominant irritable bowel syndrome. Estimates are mean (SD) or n (%).</b>

Table 1. Demographics of Tapestry participants by diagnosis of diarrhea-predominant irritable bowel syndrome. Estimates are mean (SD) or n (%).

<b>Table 2. Number of SNVs in genotypes related to candidate genes associated with BAD per participant in Tapestry database, according to ICD-10 diagnosis of diarrhea-predominant irritable bowel syndrome or control. Presented as mean (SD) [range].</b>

Table 2. Number of SNVs in genotypes related to candidate genes associated with BAD per participant in Tapestry database, according to ICD-10 diagnosis of diarrhea-predominant irritable bowel syndrome or control. Presented as mean (SD) [range].

Background: Patients with irritable bowel syndrome (IBS) often report gastrointestinal symptoms after consuming wheat/gluten-containing foods. It is, however, unclear whether gluten is the main driver of symptoms, as other immunogenic peptides, such as amylase trypsin inhibitors (ATI), poorly digestible fiber (inulin, part of FODMAP) or even the nocebo effect may contribute to symptom generation.

Aim: To evaluate whether whole wheat (containing ATIs) or purified gluten alone triggers symptoms compared to nocebo in patients with IBS adopting a gluten-free diet (GFD).

Method: We conducted a double-blind, randomized, nocebo-controlled, crossover study in adult IBS patients (Rome IV criteria) who previously perceived symptomatic improvement while on a GFD. Participants were challenged for 7 days with whole wheat, purified gluten, and nocebo (gluten-free flour) added to low-FODMAP cereal bars. Each challenge was followed by a 2-week washout. Patients remained on a GFD throughout the study. Diet adherence was assessed by a dietitian and stool gluten immunogenic peptides (GIP; Biomedal, Spain). Symptoms were assessed by IBS Symptom Severity Score (IBS-SSS); an increase >50 points was considered significantly worse. Blood samples were collected to assess immune markers and celiac genotype. Statistical comparisons used Friedman rank sum tests and paired Wilcoxon signed rank tests.

Results: Twenty-nine IBS patients (27 female, mean age 42 years) were enrolled in the study; 1 dropped. Similar proportions of patients reacted symptomatically to wheat (11/28, 39.3%), gluten (10/28, 35.7%), and nocebo (8/28, 28.6%). However, there was an overall increase in IBS symptoms after wheat (+39.5 on IBS-SSS; p=0.030) but not after gluten (+27.5; p=0.051) or nocebo (+5.5; p=0.236) challenges (Figure 1). Ten participants experienced moderate symptoms (IBS-SSS >175) during baseline and did not worsen during the challenges. Median GIP levels were 0.58 after wheat, 0.43 after gluten, and 0.09 µg/g after nocebo; p<0.001. Four out of 28 patients had GIP levels 0.10 µg/g after the gluten/wheat challenges. TNF-α, IL-8, and IFN-γ levels were low and did not increase after challenges. Celiac genes were present in 19/24 patients (HLA DQ2 n=10, DQ8 n=2, DQ7 n=9).

Conclusions: IBS patients self-reporting wheat/gluten sensitivity had worse symptoms after whole wheat, but not after purified gluten or nocebo challenges. However, similar proportions of patients reacted to each challenge, suggesting that central mechanisms play an important role in symptom genesis. One third of patients had persistently high symptoms during a GFD and challenges, suggesting that other mechanisms are underlying their IBS. Furthermore, negative GIP in some patients suggests a lack of adherence to the study protocol, highlighting the complexity and challenges of dietary intervention studies.

Figure 1. IBS-SSS scores before and after diet challenges.

Figure 1. IBS-SSS scores before and after diet challenges.

BACKGROUND. Challenges in developing medical therapies for IBS include regulatory hurdles, unknown biological mechanisms and biomarkers, poor consensus around what constitutes clinically meaningful endpoints, heterogeneity of patient population, and lack of a proof-of-concept conceptual model with predictive value in Phase IIB and III trials (Camilleri & Chang 2008, Camilleri 2017). One relatively underexplored factor involves high (40%) placebo rates (Enck & Klosterhalfen 2020) which raises bar for demonstrating a “true drug” effect, rendering many trials time consuming and expensive, delays delivery of new treatments into market, and reinforces negative stigma of IBS treatments. Detailed patient phenotyping of a broader range of variables that potentiate placebo response is needed. Patient-related data readily obtained in placebo-controlled behavioral trials are likely to have more explanatory value than general characteristics drug trials collect. AIM: To identify factors that predict treatment response of placebo-treated patients. METHOD. 145 Rome III-diagnosed IBS patients (79% F, M age = 42 yrs.) with moderate to severe GI symptoms (sx) completed baseline (BL) assessment of an NIH trial before randomized to a state-of-the-art psychological placebo (EDUcation) that mimicked elements common across therapies (e.g., alliance between patient and treating doctor) including pharmacotherapy without containing their technical properties. BL testing included measures of motivation, GI sxs, psychiatric comorbidity, distress. Clinician expectancy of treatment effectiveness and quality of working alliance by patient (pt.) were measured at end of session 1. We used dichotomous (CGI-IBS) and continuous (IBS Symptom Severity Scale) indices of global treatment response. RESULTS. For CGI, 17% were categorized as early (wk. 4) and post treatment (PT, wk. 12) responders (≧ moderate improvement). For IBS-SSS, 31% of EDU pts qualified as treatment responders (≥ 50 unit reduction) at wk. 4 and 12 (PT). IBS-SSS improvement was predicted by shorter sx duration, r (127) = -.27, p = .002, self-rated importance of achieving primary treatment goal, r (127) = .21, p = .020, as well as 2 alliance dimensions, doctor-patient bond r (124) = .19, p = .034, and their agreement around treatment goals, r (127) = .19, p = .040. Posttest CGI responder status related to clinician expectancy ratings, d = 0.38 (95% CI = 0.02 / 0.72). CONCLUSION. This study identifies a set of previously unexplored variables (alliance, motivation, clinician expectancy of sx relief) that prospectively predicted placebo response at PT. IBS pts who regarded their primary treatment goal as a more important change goal in their life to address in a supportive and collaborative relationship with a doctor with a positive treatment expectancy are more likely to be placebo responders. Funding: NIH/NIDDK 77738

Introduction
Gastrointestinal (GI) symptoms are common among “long COVID” patients and can share features with irritable bowel syndrome (IBS) and other disorders of gut-brain interaction (DGBI). A key question is whether such symptoms are truly caused by infection with the SARS-CoV-2 virus or whether they are better understood as the result of psychological factors related to the pandemic. To answer this question, we compared rates of longterm GI symptoms in patients with COVID-19 versus a unique cohort of control patients who tested negative for SARS-CoV-2 at the height of the pandemic.

Methods
Adults presenting to our institution for SARS-CoV-2 testing from April to November 2020 were prospectively enrolled in a longitudinal COVID-19 cohort. Patients were enrolled at the time of SARS-CoV-2 testing, before the test result was known. Six to 12 months later they received an electronic questionnaire asking them to report the presence and severity of current symptoms on a 5 point Likert scale. Using questions adapted from the NIH PROMIS scale, they were asked regarding GI symptoms (abdominal pain, diarrhea, constipation, nausea/vomiting, heartburn) and about sadness and anxiety. A multivariable logistic regression model was used to estimate the odds of a positive COVID test for predicting GI symptoms, stratified by the presence of sadness/anxiety.

Results
749 COVID positive and 107 COVID negative patients completed the survey. On crude analysis, there was a higher prevalence of at least one or more longterm GI symptoms in patients with vs. without COVID-19 (29 vs. 18%, p=0.01). However, COVID positive patients were also more likely to report sadness (27 vs 9% respectively, p<0.01), anxiety (34 vs 14%, p<0.01), or either symptom (37 vs 15%, p<0.01). After stratifying by the presence of sadness/anxiety, the differences between the COVID-19 positive and negative groups were no longer significant (Table 1 and Figure 1). On multivariable analysis (adjusting for age, sex, race, ethnicity, and pre-testing mental health conditions), the adjusted odds ratio (aOR) for GI symptoms was 8.26 (95% CI 4.04-16.9) for positive COVID with sadness/anxiety, 8.74 (95% CI 2.63-29.0) for negative COVID with sadness/anxiety, and 1.16 (95% CI 0.57-2.39) for positive COVID without sadness/anxiety, compared to a reference group of negative COVID without sadness/anxiety.

Conclusion
Psychological factors—namely sadness and anxiety—were strongly associated with the development of longterm GI symptoms in those who tested positive for the SARS-CoV-2 virus as well as those who tested negative. After accounting for sadness and anxiety, there was no association between COVID-19 and the development of longterm GI symptoms. Long COVID GI symptoms may be mediated in large part through coexisting anxiety and depression, similar to IBS and other DGBI.

Background
App-delivered gut-directed hypnotherapy is cheaper and more accessible than face-to-face therapy and improves gastrointestinal symptoms and psychological outcomes in patients with irritable bowel syndrome (IBS).¹It is unknown whether the observed physical and psychological improvements translate to changes in the economic burden of disease. Economic consequences of IBS are considerable and include those associated with healthcare system costs, direct management of symptoms, and from the loss of productivity at work.

Aim
To assess the economic impact of the app-delivered gut-directed hypnotherapy program, Nerva, including costs associated with the management of IBS symptoms and the loss of productivity related to absenteeism and presenteeism at work.

Methods
Patients with self-reported IBS who completed Nerva between June 2021 and June 2022 and provided symptom outcome data were included for analysis. The app guided users through the 6-week gut-directed hypnotherapy program which included daily gut-directed hypnotherapy, psychoeducation and breathing exercises. Economic outcomes were assessed at baseline, program completion and 6 months post program completion. Direct costs associated with the management of IBS symptoms were evaluated by asking users to estimate how much money they had spent on their IBS over the previous 6 months at baseline and 6 month post program completion. Users were also asked to estimate how much money they would spend over the coming 6 months at program completion. Work productivity was scored using the work productivity and activity impairment questionnaire (WPAI). Gastrointestinal symptoms were assessed using a 100-mm visual analogue scale.

Results
Gastroinestinal symptom data was obtained from 17,857 users. Majority were female (77.5%), even distribution of age and IBS symptom duration. Abdominal pain reduced from 58 (95% CI 57-59) mm at baseline to 35 (34-36) mm at program completion (p<0.001). 59% of patients responded (>30% reduction in abdominal pain). Economic data was obtained from 4,206 users. Money spent on managing IBS symptoms reduced from (baseline $1,259 (95% CI 792-1,727) to completion $644 (354-935); p=0.029) and remained stable at 6-months ($502 (380-$623); p=ns). Nerva users reported significant long-term improvements in absenteeism, presenteeism, work productivity loss and impairment in performing daily activities post program completion (Table 1).

Conclusions
App delivered gut-directed hypnotherapy is associated with an approximate halving of the lomg-term costs associated with managing IBS and improves work absenteeism, presenteeism and overall work productivity. Economic effects were maintained in the long-term and highlight the enduring efficacy of Nerva. App delivered gut-directed hypnotherapy should be considered a viable gut-brain behavioural therapy amongst IBS populations.

Background: Irritable bowel syndrome (IBS) is a chronic disorder with unpredictable onset and persistence of abdominal symptoms. Genetic and environmental differences affect variation in the IBS-risk. We explore the effects of exercise on IBS-risk, IBS symptoms and persistence of IBS in a seven-year follow-up twin study in Norway. Further, we examine the nature of the relationship between IBS and exercise.
Methods: Our study is based on participants in the Norwegian Twin Registry and includes two data collections, conducted in 2014 and 2021. Questionnaires at both time points inquired about health, psychosocial and lifestyle factors, and the 2021 data includes ratings of how the Covid-19 pandemic affected IBS symptoms. The samples included 5442 twins aged 40-80 in 2014 and 9032 twins aged 19-86 in 2021; the longitudinal sample included 2420 twins.
In 2014, data on the frequency and duration of light, moderate and vigorous exercise was collected, and in 2021 exercise level was dichotomized based on responses to items about exercise intensity, frequency, and duration. High exercisers trained at least 1-2 times a week at moderate or high intensity for at least 30 minutes, and low exercisers trained much less or not at all. Mixed effects regression models estimated the effects of exercise on IBS-risk, the reported change of IBS symptoms (worse, the same, better) during the pandemic, and persistence of IBS from 2014 to 2021. Covariates included age, sex, depression, and perceived stress. Co-twin control analysis explored whether the relationship between IBS and exercise is causal or due to shared genetic or shared environment effects.
Results: The number of reported IBS cases was 589 (10.9%) in 2014 and 831 (9.2%) in 2021. The longitudinal sample included 241 IBS cases from 2014, of which 118 were persistent cases and 123 were non-persistent; and 207 IBS cases from 2021, comprised 118 persistent cases plus 89 new cases. There was no difference (p=0.07) in the prevalence of IBS between twins who participated in the follow-up (10.0%) and those who did not (11.5%).
In 2021, the risk of IBS was lower [OR=0.84 (0.72;0.98)] among high exercisers, but the reported changes in IBS symptomatology during the pandemic did not differ by exercise group (2021) (Fig. 1). Co-twin control analysis suggests that the association between exercise and IBS reflects shared environmental, rather than causal mechanisms (Fig. 2).
The risk of persistent IBS was greater for females [OR = 1.97 (1.08;3.56)] and reduced with longer duration of vigorous exercise in 2014 [OR=0.74 (0.55;1.00)].
The effects of exercise on the IBS-risk and persistence of IBS did not retain significance after accounting for depression and stress.
Conclusion: Our results suggest that links between exercise with the risk and persistence of IBS may reflect influences related to stress and depression.

Jennifer Harris

Appearances