Phenotyping of subjects for large scale studies on patients with IBS

Effectiveness of Saccharomyces boulardii CNCM I-745 in Adult Indian Patients with Diarrhoea: A Real-world, Multicentre, Retrospective, Comparative Study

BACKGROUND

Multiple clinical studies have described the benefits of probiotic Saccharomyces boulardii (S. boulardii) CNCM I-745 against diarrhoea, but the real-world evidence supporting its use is lacking.

OBJECTIVE

To evaluate effectiveness of the S. boulardii CNCM I-745 group in a real-world setting.

METHODS

This was an electronic medical record (EMR)-based, retrospective, multicentre, comparative study in Indian adult patients presenting with diarrhoea managed between January 2020 and January 2022. Data of patients at the baseline visit, with a follow-up visit within 15 days, and who were administered S. boulardii CNCM I-745 (for the test group) or any other treatment modality excluding probiotics (for the control group) were considered. Effectiveness was evaluated on the basis of number of patients who did not complain of diarrhoea at follow-up.

RESULTS

Of 30,385 adult patients with diarrhoea, 270 patients prescribed S. boulardii CNCM I-745 were included, while the control group comprised 1457 patients. The baseline median age of the test group was 47 years (range 19-86 years), while it was 44 years (range 19-100 years) for the control group. The majority of patients in both study groups were females (56.7% in the test and 51.5% in the control group). Median duration between visits was 5 days (range 1-15 days) in both study groups. In all, 77.8% patients (95% CI 72.34-82.59) in the test group did not complain of diarrhoea at follow-up, while the proportion was 15.8% (95% CI 13.95-17.76) in the control group (p < 0.05). Odds ratio (OR) for absence of diarrhoea in the S. boulardii CNCM I-745 group versus the control group was 18.7 (95% CI 13.6-25.7, p < 0.05). For subgroups on concomitant antibiotics, a significant advantage was noted again for the test versus the control group (76.8% versus 18.4%; p < 0.05; OR: 14.7 with 95% CI 8.8-24.4; p < 0.05).

CONCLUSION

The effect of S. boulardii CNCM I-745 probiotic in controlling diarrhoea was better than anti-diarrhoeal and/or oral rehydration therapy in real-world clinical practice. The effect was similar even with concomitant antibiotic usage.

Rectal Sensory and Compliance Testing: A Method Comparison Study between High-Resolution Anorectal Manometry and Barostat Investigations

Abnormal visceral perception and motor function are often observed in patients with fecal incontinence, evacuation disorders and irritable bowel syndrome. The international anorectal physiology working group has proposed a standardization for anorectal function assessment, where rectal sensitivity testing is performed using an elastic balloon attached to a high-resolution anorectal manometry (HRAM) catheter. Rectal compliance, another component of rectal function evaluation, is a pressure-volume relationship that refers to the rectum's ability to stretch and expand as it receives and holds fecal matter. There are no data available regarding the possibility of compliance testing using HRAM, although this is theoretically possible by correcting for the elastic balloon's intrinsic properties. The gold standard for measurement of visceral sensitivity and compliance is the rectal barostat, according to the procedure described by the European COST action GENIEUR group. Data on the agreement between the two different procedures are scarce. Hence, we performed a comparative study of the HRAM and barostat investigations in 26 healthy individuals. We hypothesized that by inflating the balloon before the examination, rectal compliance can be measured with HRAM investigations, and we examined correlations and levels of agreement between the methods. Our results demonstrate that assessing rectal compliance with HRAM is technically possible; however, a strong correlation with the rectal barostat was only observed at the maximum tolerable volume (Spearman's rho = 0.7, p = 0.02). We only found moderate correlations (Spearman's rho = 0.562, p = 0.019) for compliance according to the barostat methodology and for rectal sensibility testing (Spearman's rho = 0.57, p = 0.03 for maximum tolerable volume). Bland-Altman plots showed poor levels of agreement between the methods. We conclude that HRAM and the rectal barostat cannot be used interchangeably for compliance or sensitivity assessments. We suggest the development of a non-elastic balloon with a fixed size and shape to assess rectal sensory function and compliance in HRAM testing.

Gender Influences Gut Microbiota among Patients with Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disease that affects approximately 11% of the general population. The gut microbiota, among other known factors, plays a substantial role in its pathogenesis. The study aimed to characterize the gut microbiota differences between patients with IBS and unaffected individuals, taking into account the gender aspect of the patients and the types of IBS determined on the basis of the Rome IV Criteria, the IBS-C, IBS-D, IBS-M, and IBS-U. In total, 121 patients with IBS and 70 unaffected individuals participated in the study; the derived stool samples were subjected to 16S rRNA amplicon sequencing. The gut microbiota of patients with IBS was found to be more diverse in comparison to unaffected individuals, and the differences were observed primarily among Clostridiales, Mogibacteriaceae, Synergistaceae, Coriobacteriaceae, Blautia spp., and Shuttleworthia spp., depending on the study subgroup and patient gender. There was higher differentiation of females' gut microbiota compared to males, regardless of the disease status. No correlation between the composition of the gut microbiota and the type of IBS was found. Patients with IBS were characterized by more diverse gut microbiota compared to unaffected individuals. The gender criterion should be considered in the characterization of the gut microbiota. The type of IBS did not determine the identified differences in gut microbiota.

Head and Neck Pain Drawing Area Correlates With Higher Psychosocial Burden But Not With Joint Dysfunction in Temporomandibular Disorders: A Cross-Sectional Study

Head and neck pain drawings have been introduced as part of the diagnostic gold standard for temporomandibular disorders (TMD). We aimed to quantify the spatial extent of pain in TMD patients and to analyze its association with further clinical findings. In a cross-sectional study, 90 patients (median age = 38 years; n women = 68) were diagnosed according to the DC/TMD. Intra-articular disorders were either confirmed or rejected by magnetic resonance imaging. The patients shaded all painful areas in a sketch of the left and right side of a face. A grid template was placed over the drawings and each region that contained markings was scored as painful. The correlation between the calculated area and the psychosocial variables (DC/TMD axis II) as well as the influence of pain lateralization were investigated using Spearman correlation, Mann-Whitney-U and chi-square tests. Pain affected all facial areas but concentrated on the regions of the temporomandibular joint and masseter origin. Thirty-nine percent reported purely unilateral pain, which was associated with structural TMJ findings in 77% of cases. Individuals with bilateral pain and those with greater spatial spread of pain had significantly higher scores on all axis II variables, except for functional limitation of the jaw. PERSPECTIVE: Head and neck pain drawings can contribute to a stratification of TMD patients. A greater extent of pain as well as pain bilateralization is associated with higher levels of emotional distress, pain chronicity and somatization, but not with functional impairment. Unilateral reporting of pain is associated with more intra-articular disorders.

Factors influencing rectal hypersensitivity in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

A frequent, although not universal, feature of irritable bowel syndrome (IBS) is heightened sensitivity to mechanical stimulation of the rectum, termed rectal hypersensitivity (RH). Differences in RH-based on sex, IBS subtype, IBS diagnostic criteria and age of population studied are incompletely understood. We aimed to determine whether IBS population had lower pain thresholds than healthy controls.

METHODS

We searched MEDLINE and EMBASE databases (1970-2021). Prospective studies that compared pain/discomfort thresholds to mechanical rectal stimuli in IBS and healthy controls were included. Data were pooled for meta-analyses and effect sizes were calculated with 95% confidence interval (CIs).

RESULTS

Our search strategy identified 809 studies of which 32 studies met the inclusion criteria. Reduced rectal pain thresholds was more common in IBS patients compared to healthy controls with an effect size of 1.00 95% CIs (0.77-1.24) (p < 0.0001) (I²  = 78.6%). The pediatric IBS population had lower pain thresholds than adult IBS populations (p = 0.05) but no difference based on IBS diagnostic criteria, subtype or sex.

CONCLUSION & INFERENCES

The results suggest that reduced rectal pain threshold to experimental stimulation is far more common in IBS patients than healthy controls. Further research is required to understand the pathophysiological and therapeutic implications of rectal sensitivity such as its role in measuring response to treatment and prognosis in IBS.

Obesity Contributes to Inflammation in Patients with IBS via Complement Component 3 and C-Reactive Protein

Irritable Bowel Syndrome (IBS) is usually a lifelong state that disturbs the digestive system. IBS has been linked to low-grade inflammation and the release of inflammatory mediators into the bloodstream. This could be associated with the degree of obesity presented by patients with IBS. Reports imply that IBS is more frequent in obese patients than in the overall population, with a prevalence of up to 31%. Here, we evaluated the serum levels of immunological and inflammation molecules and their correlation with Body Mass Index in IBS patients and the healthy control (HC). Seventy-nine serum samples of the IBS patients and thirty-five of the HC group were analyzed to determine the levels of each molecule and compare them with their BMI. Serum levels of C3 and C4 were significantly increased in IBS patients. C3 and C4 levels were higher in IBS-M and IBS-D subtypes compared with the HC group. When patients were grouped by BMI, a positive correlation between serum C3 (r = 0.49, p < 0.0001) and CRP (r = 0.40, p < 0.001) levels was found. Our results show, for the first time, a correlation between immunological molecules and BMI in IBS patients, suggesting that the inflammatory nature of obesity could contribute to the development of the symptoms in IBS through the stimulation and release of proteins as complement components and CRP.

Identification of bacterial lipopeptides as key players in IBS

OBJECTIVES

Clinical studies revealed that early-life adverse events contribute to the development of IBS in adulthood. The aim of our study was to investigate the relationship between prenatal stress (PS), gut microbiota and visceral hypersensitivity with a focus on bacterial lipopeptides containing γ-aminobutyric acid (GABA).

DESIGN

We developed a model of PS in mice and evaluated, in adult offspring, visceral hypersensitivity to colorectal distension (CRD), colon inflammation, barrier function and gut microbiota taxonomy. We quantified the production of lipopeptides containing GABA by mass spectrometry in a specific strain of bacteria decreased in PS, in PS mouse colons, and in faeces of patients with IBS and healthy volunteers (HVs). Finally, we assessed their effect on PS-induced visceral hypersensitivity.

RESULTS

Prenatally stressed mice of both sexes presented visceral hypersensitivity, no overt colon inflammation or barrier dysfunction but a gut microbiota dysbiosis. The dysbiosis was distinguished by a decreased abundance of Ligilactobacillus murinus, in both sexes, inversely correlated with visceral hypersensitivity to CRD in mice. An isolate from this bacterial species produced several lipopeptides containing GABA including C14AsnGABA. Interestingly, intracolonic treatment with C14AsnGABA decreased the visceral sensitivity of PS mice to CRD. The concentration of C16LeuGABA, a lipopeptide which inhibited sensory neurons activation, was decreased in faeces of patients with IBS compared with HVs.

CONCLUSION

PS impacts the gut microbiota composition and metabolic function in adulthood. The reduced capacity of the gut microbiota to produce GABA lipopeptides could be one of the mechanisms linking PS and visceral hypersensitivity in adulthood.

Serotonin type 3 receptor subunit gene polymorphisms associated with psychosomatic symptoms in irritable bowel syndrome: A multicenter retrospective study

BACKGROUND

Single-nucleotide polymorphisms (SNPs) of the serotonin type 3 receptor subunit (HTR3) genes have been associated with psychosomatic symptoms, but it is not clear whether these associations exist in irritable bowel syndrome (IBS).

AIM

To assess the association of HTR3 polymorphisms with depressive, anxiety, and somatization symptoms in individuals with IBS.

METHODS

In this retrospective study, 623 participants with IBS were recruited from five specialty centers in Germany, Sweden, the United States, the United Kingdom, and Ireland. Depressive, anxiety, and somatization symptoms and sociodemographic characteristics were collected. Four functional SNPs — HTR3A c.-42C>T, HTR3B c.386A>C, HTR3C c.489C>A, and HTR3E c.*76G>A — were genotyped and analyzed using the dominant and recessive models. We also performed separate analyses for sex and IBS subtypes. SNP scores were calculated as the number of minor alleles of the SNPs above. The impact of HTR3C c.489C>A was tested by radioligand-binding and calcium influx assays.

RESULTS

Depressive and anxiety symptoms significantly worsened with increasing numbers of minor HTR3C c.489C>A alleles in the dominant model (F_depressive = 7.475, P_depressive = 0.006; F_anxiety = 6.535, P_anxiety = 0.011). A higher SNP score (range 0-6) was linked to a worsened depressive symptoms score (F = 7.710, P-linear trend = 0.006) in IBS. The potential relevance of the HTR3C SNP was corroborated, showing changes in the expression level of 5-HT₃AC variant receptors.

CONCLUSION

We have provided the first evidence that HTR3C c.489C>A is involved in depressive and anxiety symptoms in individuals with IBS. The SNP score indicated that an increasing number of minor alleles is linked to the worsening of depressive symptoms in IBS.

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT₃ receptor family. 5-HT₃Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT₃R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D.

Examining the optimal cutoff values of HADS, PHQ-9 and GAD-7 as screening instruments for depression and anxiety in irritable bowel syndrome

BACKGROUND

Self-rating scales are frequently used to screen for anxiety and depression in patients with irritable bowel syndrome (IBS). Different cutoff values are recommended in literature, and guidelines have suggested the use of other screening instruments over time. The aim of this study was to assess the correlation between the most commonly used psychological screening instruments for anxiety and depression in IBS and to compare custom cutoff scores for these instruments.

METHODS

Irritable bowel syndrome patients (n = 192) completed several questionnaires including the Hospital Anxiety and Depression Scale (HADS, HADS-A and HADS-D subscale), Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7). Agreement at different cutoff points, for depressive and anxiety disorder, was assessed by use of the Gwet AC1 coefficient.

KEY RESULTS

Hospital Anxiety and Depression Scale (HADS)-D and PHQ-9 scores, and HADS-A and GAD-7 scores showed high correlations (r_s  = 0.735 and r_s  = 0.805, respectively). For depressive disorder, a Gwet AC1 value of 0.829 was found when recommended cutoff points from literature were compared (PHQ-9 cutoff ≥10, HADS-D cutoff ≥8). For anxiety disorder, a Gwet AC1 value of 0.806 was found when recommended cutoff points from literature were compared (GAD-7 cutoff ≥10, HADS-A cutoff ≥8). Even higher agreements were found when higher HADS cutoff values were chosen, with impact on sensitivity and specificity.

CONCLUSIONS & INFERENCES

Custom cutoff values deem the HADS subscales (HADS-D and HADS-A) concordant to PHQ-9 and GAD-7 scores. The choice of a cutoff value has substantial impact on sensitivity/specificity and is dependent on patient population, setting, and the purpose of use.

Role of psychological questionnaires in clinical practice and research within functional gastrointestinal disorders

Functional gastrointestinal (GI) disorders, also known as disorders of gut-brain interaction (DGBI), affect 40% of the global population. Up to two-thirds of patients with FGIDs experience a major psychological disorder making a thorough psychosocial assessment a critical part of patient care as it can impact treatment approach. Many psychological questionnaires exist in the clinical realm serving different purposes including screening for anxiety and depression, somatization symptoms, health-related anxiety, illness impact, and health-related quality of life. Given the abundance of questionnaires used to screen for similar psychiatric comorbidities, correlation between different instruments is needed to allow for pooling of data. In this issue of Neurogastroenterology & Motility, Snijkers et al. conducted the first comparative study to assess the correlation between the Hospital Anxiety and Depression Scale (HADS) and the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) to determine optimal cutoffs for diagnosis of depressive and anxiety disorders in a cohort of irritable bowel syndrome patients. The biopsychosocial framework as it applies to FGID has led to the inclusion of both psychosocial assessments in clinical management and research protocols. Future directions include the development of symptom-specific questionnaires for groups of FGIDs, culturally specific psychosocial questionnaires, and inclusion of psychosocial well-being as primary or secondary outcomes in clinical research trials. In this review, we aim to explore the role of psychological questionnaires in clinical care and research trials and share practical tips on incorporating a biopsychosocial framework in the care of patients with FGIDs.

Irritable Bowel Syndrome Prevalence among Participants of Woodstock Rock Festival in Poland Based on Rome IV Criteria Questionnaire

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder (FGID), in which etiology and pathogenesis are not fully explored. There is an ongoing need for more population studies adhering to new ROME IV criteria. In the current study, which follows our previous investigation among participants of the Woodstock Rock Festival in Poland, we aimed to evaluate the prevalence of IBS and its relation to age, gender, education, and IBS type.

METHODS

Rome IV criteria questionnaire was used to assess abdominal complaints of 386 participants of the Woodstock Rock festival 2018.

RESULTS

Analyzed data revealed that Rome IV criteria were met by 42 participants (11.41%), 11 men and 31 women (p = 0.0028), with following types of IBS: IBS-M (mixed form) 55%, IBS-D (with diarrhea) 33%, IBS-U (unclassified) 10%, IBS-C (with constipation) 2%. No statistically significant correlation between IBS prevalence and age, gender, or education (p > 0.05) was found.

CONCLUSIONS

The prevalence of IBS among major rock festival participants in Poland was high. Women met the criteria more often than men, which is consistent with global epidemiology for many years. Among participants of the Woodstock Rock Festival, the most frequent subtype was IBS-M, the rarest-IBS-C. There is a need of conducting cohort studies in bigger groups in our population.

The Validity of Somatic Symptom Disorder in Patients With Gastrointestinal Complaints

BACKGROUND AND GOAL

The current diagnostic concept of somatic symptom disorder (SSD) aims to capture psychological burden due to bodily complaints independent of the medical cause. The aim of this study was to compare patients with chronic gastrointestinal (GI) complaints with SSD (SSD+) and without SSD (SSD-) along sociodemographic, clinical, and psychological characteristics.

STUDY

This cross-sectional study included 199 patients (n=92 SSD+ and n=107 SSD-) with distressing and chronic abdominal/lower GI complaints (≥6 mo) recruited from several primary, secondary, and tertiary medical care units. SSD+ patients were separated from SSD- patients by psychobehavioral positive criteria. Psychological distress (somatization, depression, anxiety, and illness anxiety) and risk factors (adverse childhood experiences, insecure attachment, mentalizing capacity, and levels of personality functioning) were measured. Nonparametric group comparisons were performed to analyze the differences of sociodemographic, clinical, and psychological characteristics between SSD+ and SSD- patients.

RESULTS

About half of the SSD+ patients had a functional GI disorder and a third had an inflammatory bowel disease. SSD+ patients reported higher GI pain severity, higher health-related and work-related impairment, and higher psychological distress, especially illness anxiety, as well as higher mentalizing and personality functioning deficits.

CONCLUSIONS

Overall, psychobehavioral positive criteria of SSD seem to be a valid identifier of patients exhibiting a high psychological burden, independent of the medical explanation of the GI complaints. There is a substantial overlap of SSD and general mental burden, but also evidence for a specific disease entity.

The alternative serotonin transporter promoter P2 impacts gene function in females with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gut-brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation-predominant IBS (IBS-C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta-analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS-C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow-up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS-C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis.

Sexual dimorphism in maternally separated rats: effects of repeated homotypic stress on gastrointestinal motor functions

Experiencing stressful events during early life has been considered as a risk factor for development of functional gastrointestinal disorders in adulthood. This study aimed to investigate the sex-related differences in stress-induced gastrointestinal (GI) dysmotility in rats exposed to neonatal maternal separation (MS). Newborn pups were removed from mothers for 180 min from postnatal day-1 to day-14. Experiments were performed in male and female offsprings at adulthood. Elevated plus maze (EPM) test was used to assess MS-induced anxiety-like behaviors. Ninety minute of restraint stress was applied for once or 5 consecutive days for acute stress (AS) or repeated homotypic stress (RHS), respectively. Measurement of fecal output (FO) and gastric emptying (GE), and hypothalamic microdialysis were performed. Both in males and females, MS produced anxiety-like behaviors. AS delayed GE and increased FO in all groups. In RHS-loaded MS females, AS-induced alterations in GE and FO were restored, however, no adaptation was observed in male counterparts. Regardless of sex and neonatal stress experience, AS significantly increased corticotropin-releasing factor (CRF) release from paraventricular nucleus of hypothalamus, whereas females were found more susceptible than males. Following RHS, AS-induced elevations in CRF release were attenuated only in MS females, but not in males. Both females and males seem to be prone to AS-induced alterations in hypothalamic CRF system and in GI motor functions. Neonatal MS disturbs chronic stress coping mechanisms in males. Conversely, females are likely to circumvent the deleterious effects of neonatal MS on GI functions through developing a habituation to prolonged stressed conditions.

Rectal Hypersensitivity in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Abdominal pain is a key symptom of inflammatory bowel disease (IBD), particularly in active IBD, but also occurs in patients with quiescent disease suggesting that mechanisms other than active inflammation may be responsible. Putative hypothesis to explain chronic abdominal pain in patients with quiescent IBD includes crossover with irritable bowel syndrome where rectal hypersensitivity is common and has pathophysiological implications. In contrast, in IBD, the role of rectal hypersensitivity has not been established. We aimed to determine if rectal hypersensitivity was more common in IBD compared to a healthy control population. We searched MEDLINE and EMBASE databases (1970-2018). Prospective studies that measured pain/discomfort thresholds to mechanical rectal stimuli in IBD and healthy controls were included. Data were pooled for meta-analysis and effect sizes were calculated with 95% confidence intervals (CIs). Our search strategy identified 222 citations of which 8 met the inclusion criteria, covering 133 individuals with IBD (67 men), aged between 10 and 77 compared to 99 healthy controls (55 men), aged between 10 and 67. The prevalence of rectal hypersensitivity in IBD compared to healthy controls was similar with an effect size of 0.59 (95% CIs: -0.27 to 1.44, P = .16, I ² = 87.3%). Subgroup analysis did show a significant effect size for patients compared to healthy controls with active disease (1.32) but not for quiescent disease (-0.02). These results suggest that reduced rectal pain thresholds to experimental stimulation are not seen in IBD populations except during active flares of the disease. Further research is required to understand the pathophysiology of chronic abdominal pain in quiescent IBD populations with and without chronic abdominal pain to identify appropriate management strategies.

A comparison using standardized measures for patients with irritable bowel syndrome: Trust in the gastroenterologist and reliance on the internet

BACKGROUND

Irritable bowel syndrome (IBS) patients' use of the Internet for health information interacts with the way they trust their gastroenterologist. No standardized measure has targeted IBS patients and gastroenterologists specifically, nor their use of the Internet. The aims of this paper were as follows: the development of a scale that measures an IBS patient's trust in their gastroenterologist, the development of a scale measuring an IBS patient's reliance on Internet health information, and testing the hypothesis that IBS patients, who use the Internet for IBS-related information, trust their gastroenterologist less than those who do not.

METHOD

A total of 82 patients (mean age 49, SD = 14.62) diagnosed with IBS completed two questionnaires: one about trust in their gastroenterologist and the other about the reliance on Internet health information regarding IBS. The two questionnaires were built using current literature as well as our previous qualitative research. The statistical computations were performed using the SPSS 20 program.

KEY RESULTS

Both questionnaires proved to be reliable in measuring gastroenterologist-IBS patient trust (alpha = 0.87) and Internet information reliance (alpha = 0.88), respectively. The IBS patients who did not look for information about IBS over the Internet had significantly higher trust in their gastroenterologist compared with those who did (U = 535.5; z = -2.26; P < 0.05).

CONCLUSIONS

We developed two ready-to-use scales to measure both the gastroenterologist-IBS patient's trust and the IBS patient's reliance on the Internet. Further studies will be able to explore the interaction among all variables in IBS patients' trust.

Health-Related Quality of Life in Irritable Bowel Syndrome: A Systematic Review and Meta-analysis

Irritable bowel syndrome (IBS) affects up to 20% of the global population and is associated with impaired health-related quality of life (HRQoL). This systematic review and meta-analysis aimed to investigate differences in HRQoL of those with IBS compared with healthy controls and to examine whether HRQoL improves following psychological intervention. Online databases were searched for articles from 2002 to 2017. Studies were screened and data extracted according to predetermined criteria. A total of 4,154 citations were identified from which 36 were eligible for inclusion. Eight studies compared HRQoL of those with IBS (n = 822) with that of healthy individuals (n = 3,809). Those with IBS suffered significant impairment across all HRQoL domains compared with healthy individuals, with the majority of effects (Cohen's d) being moderate to large. Twenty-eight studies investigated HRQoL in IBS following psychological intervention (n = 1,308) relative to controls (n = 1,006). All HRQoL domains improved with large effects following treatment; however, maintenance of these effects was inconsistent. Those with IBS experience poorer HRQoL than the wider community; nevertheless, psychological interventions are associated with improved HRQoL across all domains. High-quality studies are needed to better inform gastroenterological nurses of which interventions are most efficacious in alleviating the burden of IBS, and which IBS subpopulations would benefit.

Different Dimensions of Affective Processing in Patients With Irritable Bowel Syndrome: A Multi-Center Cross-Sectional Study

Objective: Deficits in affective processing are associated with impairments in both mental and physical health. The role of affective processing in patients with functional somatic complaints such as irritable bowel syndrome (IBS) remains unclear. Most studies have focused on the capacity for emotional awareness and expression, but neglect other dimensions of affective processing. Therefore, this study aimed to systematically analyze differences in six different dimensions of affective processing between patients with IBS and healthy controls (HCs). Additionally, we exploratively investigated the impact of IBS symptom severity, psychological distress, and attachment styles on affective processing in IBS. Methods: A controlled cross-sectional multi-center study was conducted. Overall, 127 patients with IBS were compared with 127 matched HCs using multivariate analysis of variances. Affective processing was operationalized in line with the affect cascade model on six specific dimensions: emotional experience, emotional awareness, affect tolerance, affect differentiation, affect regulation, and emotional communication. They were measured using two subscales of the Mentalizing Questionnaire (MZQ) and four subscales of the Operationalized Psychodynamic Diagnosis-Structure Questionnaire (OPD-SQ). Linear regression analysis was used to investigate the influence of IBS symptom severity (IBS-Severity Scoring System, IBS-SSS), depression (Patient Health Questionnaire, PHQ-9), anxiety (General Anxiety Disorder, GAD-7), and anxious and avoidant attachment styles (Experiences in Close Relationships Scale, ECR-RD12) on the different dimensions of affective processing in IBS. Results: Patients with IBS compared to HCs showed deficits in all six dimensions of affective processing. Deficits were largest for affect tolerance (d = 0.849) and lowest for emotional experience (d = 0.222) and emotional awareness (d = 0.420). Moderate effect sizes were found for affect differentiation (d = 0.773), emotional communication (d = 0.665), and affect regulation (d = 0.552). Moreover, explorative analyses indicated that affective processing in patients with IBS was significantly influenced by levels of anxiety and insecure attachment. Conclusion: The results indicate a specific pattern of affective processing abilities in patients with IBS. The deficits in affective processing are more prominent in the area of understanding and tolerating difficult affective states than experiencing affective states. This opens interesting perspectives for the development of specific psychotherapeutic interventions. Clinical Trial Registration: DRKS00011685.

A Novel Method to Classify and Subgroup Patients With IBS Based on Gastrointestinal Symptoms and Psychological Profiles

INTRODUCTION

Conventionally, patients with irritable bowel syndrome (IBS) are subgrouped based on their predominant bowel habit. Given the relevance of psychological comorbidity to IBS symptoms, our aim was to explore an alternative approach to subgrouping by incorporating factors beyond stool form and frequency.

METHODS

We collected demographic, symptom, and psychological health data from 1,375 adult subjects in the community who self-identified as having IBS, identifying 2 cohorts meeting either Rome III or Rome IV criteria. In each cohort, we performed latent class analysis, a method of model-based clustering, to identify specific subgroups (clusters). For each cluster, we drew a radar plot and compared these by visual inspection, describing cluster characteristics.

RESULTS

In total, 1,080 individuals met the Rome III criteria for IBS, and 811 met the Rome IV criteria. In both cohorts, a 7-cluster model was the optimum solution, and the characteristics of the clusters were almost identical between Rome III and IV. Four clusters were defined by the pattern of gastrointestinal symptoms (loose stools and urgency or hard stools and bloating), further differentiated by the presence of abdominal pain not relieved by defecation, and by the extent of psychological comorbidity. Two clusters had below-average gastrointestinal symptoms, differentiated by the extent of psychological comorbidity. The final cluster had well-above-average gastrointestinal symptoms and high levels of psychological comorbidity. The proportion of subjects with severe IBS symptom scores, high levels of perceived stress, and high levels of gastrointestinal symptom-specific anxiety was significantly higher in clusters with high psychological comorbidity (P < 0.001).

DISCUSSION

Latent class analysis identified 7 distinct IBS subgroups characterized by varying degrees of gastrointestinal symptoms, extraintestinal symptoms, and psychological comorbidity. Further research is needed to assess whether they might be used to direct treatment.

Stressful Life Events Moderate the Relationship Between Changes in Symptom Severity and Health-related Quality of Life in Patients With Irritable Bowel Syndrome

OBJECTIVES

The relationship between changes in symptom severity and health-related quality of life (HRQOL), which may be impacted by stressful life events, in irritable bowel syndrome (IBS), is unclear. Therefore, we investigated the relationship between changes in symptom severity and HRQOL and examined the moderating role of stressful life events in patients with IBS.

METHODS

This study is part of a cohort follow-up study on psychological factors in patients with IBS in tertiary care, and it included 158 patients. In addition to symptom severity and HRQOL, stressful life events were assessed by the Social Readjustment Rating Scale (SRRS). The relationship between symptom severity and HRQOL and the moderating role of stressful life events (in the 12 mo before the follow-up assessment) were analyzed.

RESULTS

The majority of participants had moderate levels of stressful life events (41.8%), followed by those who had mild levels (39.2%) and severe levels (19.0%) of stressful life events. Symptom severity could predict HRQOL, and the relationship between symptom severity and HRQOL was affected by the level of stressful life events. Compared with mild levels of stressful life events, a severe level of stressful life events significantly affected the relationship between changes in symptom severity and HRQOL (Z=-3.048, P<0.01). A similar result was found when comparing moderate and severe levels of stressful life events (Z=-1.810, P<0.10).

CONCLUSIONS

The study demonstrated that symptom severity predicted HRQOL during the progression of IBS and that stressful life events moderated the impact of symptom severity on HRQOL. The more stressful life events an IBS patient experiences, the less predictable the relationship is between changes in symptom severity and HRQOL.

Fructose and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic disorder characterised by recurrent abdominal pain or discomfort and transit disturbances with heterogeneous pathophysiological mechanisms. The link between food and gastrointestinal (GI) symptoms is often reported by patients with IBS and the role of fructose has recently been highlighted. Fructose malabsorption can easily be assessed by hydrogen and/or methane breath test in response to 25 g fructose; and its prevalence is about 22 % in patients with IBS. The mechanism of fructose-related symptoms is incompletely understood. Osmotic load, fermentation and visceral hypersensitivity are likely to participate in GI symptoms in the IBS population and may be triggered or worsened by fructose. A low-fructose diet could be integrated in the overall treatment strategy, but its role and implication in the improvement of IBS symptoms should be evaluated. In the present review, we discuss fructose malabsorption in adult patients with IBS and the interest of a low-fructose diet in order to underline the important role of fructose in IBS.

Patients with Multiple Functional Gastrointestinal Disorders (FGIDs) Show Increased Illness Severity: A Cross-Sectional Study in a Tertiary Care FGID Specialty Clinic

OBJECTIVES

Overlaps between different functional gastrointestinal disorders (FGIDs) are common. However, little is known about the impact of this overlap on patients' health status. This study is aimed at analyzing the differences between patients with multiple as compared to one single FGID.

METHODS

A retrospective, cross-sectional study was conducted with patients presenting to a tertiary care FGID specialty clinic between 06/2012 and 01/2015 (n = 294). They were characterized primarily according to their GI symptom severity (IBS-SSS) and secondarily to their physical as well as psychosocial symptom burden, quality of life, health care utilization, and work-related impairment. Differences between patients with >1 vs. 1 FGID were analyzed.

RESULTS

Of the 294 patients, 92.2% fulfilled the Rome III criteria for any FGID, and 48.0% had >1 FGIDs. FGID patients had a median age of 38 [23.0] years; 72.0% were female. Median GI symptom severity (IBS-SSS) scores were 339 [126] and 232 [163] in patients with >1 and 1 FGID, respectively (p < .001). Furthermore, patients with >1 FGIDs had higher general somatic symptom severity, higher illness anxiety, lower quality of life, and more work-related impairment. Almost no differences were found regarding their somatic as well as mental comorbidities.

CONCLUSIONS

Multiple FGIDs are associated with an increased risk for complicated courses of illness as reflected in higher GI and somatic symptom severity, as well as stronger psychosocial and diet- and work-related impairment. Stepped and interdisciplinary models of care including psychosocial expertise and dietary advice are needed, especially for patients with multiple FGIDs.

Relationship between adverse childhood experiences and illness anxiety in irritable bowel syndrome - The impact of gender

OBJECTIVE

Irritable bowel syndrome (IBS) is a functional disorder with a complex biopsychosocial etiopathogenesis. Various psychosocial factors like adverse childhood experiences (ACE) and illness anxiety appear to be relevant, but underlying mechanisms are still not fully understood. Furthermore, there are indicators of gender specific effects of ACE on IBS. Therefore, this study analyzed group differences between IBS patients and healthy controls (HCs) according to ACE and illness anxiety, and the relationship between ACE and illness anxiety by taking gender differences into consideration.

METHODS

A cross-sectional multi-center study was conducted comparing IBS patients with HCs. Illness anxiety was recorded using the Whiteley-Index-7, childhood adversities via the 10-item Adverse-Childhood-Experiences-score, anxiety by the Generalized Anxiety Disorder seven-item questionnaire and depressive symptoms using the nine-item depression module of the patient-health-questionnaire. Group differences between IBS patients and HCs were analyzed and correlation analyses were performed.

RESULTS

Overall, 127 gender and education matched participants per group were included. Compared to HCs, IBS patients were characterized by higher prevalences for adverse childhood experiences (63.8% vs. 48.0%, p = .02, OR = 1.33) and increased levels of illness anxiety (p < .001, η² = 0.595). Taking into account gender specific effects, there was a significant correlation between adverse childhood experiences and illness anxiety in female IBS patients, but not in male (r = 0.242, p = .03 vs. r = 0.162, p = .29). However, after controlling for depression and anxiety, this correlation disappeared.

CONCLUSION

Our findings suggest a possible gender-specific association of ACE with illness anxiety in female IBS patients that might be linked to increased levels of depression and anxiety.

TRIAL REGISTRATION

DRKS00011685.

Does symptom activity explain psychological differences in patients with irritable bowel syndrome and inflammatory bowel disease? Results from a multi-center cross-sectional study

OBJECTIVE

Irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBD) have similar symptoms and are affected by psychological factors via gut-brain-interactions. However, previous studies on IBS and IBD showed inconsistent results regarding psychological factors, potentially because they failed to consider the impact of symptom activity. The aim of this study was 1) to compare psychological distress and psychological risk factors among patients with IBS, IBD and healthy controls (HC), and 2) to assess the impact of symptom activity.

METHODS

A controlled cross-sectional study was conducted. Patients with IBS and IBD were recruited in several primary, secondary, and tertiary medical care units between 02 and 12/2017 in Germany. Overall, 381 matched participants (127/group, 63% female) were included. For the second analyses, patients with IBD were distinguished in patients with active (n = 93) and non-active (n = 34) symptoms. Psychological distress (somatization, depression, anxiety, and illness anxiety) and risk factors (adverse childhood experiences, attachment style, and mentalizing capacity) were measured.

RESULTS

Patients with IBS showed higher psychological distress and more psychological risk factors than patients with IBD and HC. However, patients with IBD and active symptoms showed similar psychological distress than patients with IBS, except for lower illness anxiety (p < .001, η² = 0.069).

CONCLUSION

With the exception of higher illness anxiety in IBS patients, differences in psychological factors between patients with IBS and IBD were more strongly associated with symptom activity than with the underlying diagnosis. Therefore, this study challenges previous concepts of distinguishing functional and organic gastrointestinal diseases, but highlights the role of symptom activity and illness anxiety.

TRIAL REGISTRATION

DRKS00011685.

Phenotypic features of patients with post-infectious irritable bowel syndrome

Background

Although there are many published data in the literature about irritable bowel syndrome (IBS), there are only few data on the long term evolution of patients with post infectious irritable bowel syndrome (PI-IBS) and associated conditions.

Aims

The purpose of our research was to study the evolution of PI-IBS patients in a single tertiary center over a period of four years.

Study Design

Our research was a longitudinal retrospective study.

Methods

We carried out this study based on the survey of the patients records. We recruited two groups of patients: patients with classical IBS and patients with PI-IBS. The IBS diagnosis was established using ROME III criteria, which were used at that time. We compared the two groups of patients by analyzing the demographic data, comorbidities, treatment that was prescribed, and evolution after treatment for a period of 48 month on average.

Results

From a total of 592 patients that were diagnosed with IBS between 2013-2016, we identified a subgroup of 64 patients with PI-IBS. These patients were also divided into two subgroups, depending on the main symptoms, 51 with PI-IBS - diarrhea and 13 of them with PI-IBS-constipation. IBS is the most commonly diagnosed among women, 45 patients were women and 15 were men. Regarding the frequency of occurrence of a certain subtype by gender, no significant differences were observed in both IBS and PI-IBS. We noticed a higher incidence of patients residents of an urban community in both groups.The main symptoms were: abdominal pain and bowel disorders (constipation, diarrhea).There was a significant difference between the two groups regarding the onset of the symptoms. From the total of 64 patients with PI-IBS, 88.3% presented a sudden onset of symptoms (mainly abdominal pain) unlike the other group where 81% of them presented a progressive onset, with an insidious progress and sporadic exacerbation. Most patients (65.63%) presented an improvement after the treatment, 25.56% oscillating periods but with a significant decrease of intensity of symptoms, and 7.8% did not show improvement after treatment.The most common associated diseases were depression and anxiety (34.37%).

Conclusion

IBS is generally present in approximately 11% of the population, with PI-IBS patients accounting for approximately 10% of them. Female gender is more common in both IBS and PI-IBS. Patients with PI-IBS are a burden in the health system in terms of the important economic resources used for diagnosis and treatment.

Visceral sensitivity remains stable over time in patients with irritable bowel syndrome, but with individual fluctuations

BACKGROUND

Visceral hypersensitivity in irritable bowel syndrome (IBS), measured with rectal balloon distensions, using a barostat, has been suggested to be a phenomenon that is reduced due to habituation at repeated investigations. We investigated the stability of rectal sensitivity in patients with IBS who had undergone a previous rectal barostat study and assessed variations in symptom pattern and severity in relation to rectal sensory function.

METHOD

Irritable bowel syndrome patients, who had previously been undergone a rectal barostat study, were included. All patients underwent a second study 8-12 years later. Symptoms were characterized by use of questionnaires.

KEY RESULTS

We included 26 subjects (17 females, median age at the index investigation 44.5 (21-61) years). Pressure and volume sensory thresholds were unchanged at the follow-up compared with the index investigation (P > 0.05 for all). At the index investigation, 8/26 patients had rectal hypersensitivity of which four were reclassified as normosensitive, and sixfrom normo- to hypersensitive, meaning that 10/26 patients were hypersensitive at the follow-up investigation. IBS-QOL had improved significantly in six of nine domains at follow-up (P < 0.05 for all). There were no differences in anxiety, depression, IBS symptom severity, or somatization (P > 0.05) at follow-up. None of these were associated with change in rectal sensitivity at follow-up.

CONCLUSIONS AND INFERENCES

Rectal hypersensitivity and IBS symptoms remained stable at the group level over 8-12 years in IBS patients, even though individual fluctuations were noted. Our findings contradict previous findings indicating that visceral hypersensitivity is an unstable trait.

New treatments and therapeutic targets for IBS and other functional bowel disorders

Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.

Systemic cytokines are elevated in a subset of patients with irritable bowel syndrome but largely unrelated to symptom characteristics

BACKGROUND

Serum levels of pro-inflammatory cytokines tend to be increased in irritable bowel syndrome (IBS) patients, or subgroups thereof. Still, the link between cytokine levels and IBS symptoms is unclear. We aim to determine systemic cytokine levels in IBS patients and healthy subjects (HS), confirm the presence of a subset of patients with an increased immune activity and to establish if cytokines are linked to IBS symptoms and pathophysiological factors.

METHODS

Serum levels of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF), and IL-10 were measured. All subjects reported IBS symptoms using validated questionnaires and underwent colonic sensorimotor testing. Multivariate supervised orthogonal partial least squares-discriminant analysis (OPLS-DA) and unsupervised principal component analysis (PCA) and hierarchical cluster analysis (HCA) were implemented.

KEY RESULTS

Irritable bowel syndrome patients (n = 246) had higher serum levels of IL-1β, IL-6, IL-8, TNF, and IL-10 compared to HS (n = 21); however, serum cytokine profiles could not discriminate patients from HS. Moreover, cytokine levels were not correlated with symptoms among patients. Supervised OPLS-DA identified 104 patients (40% of patients) and unsupervised HCA analysis identified 49 patients (20%) with an increased immune activity indicated by elevated levels of serum cytokines compared to HS and the other patients. However, irrespective of how patients with increased immune activity were identified they were symptomatically similar to patients with no indication of increased immune activity.

CONCLUSIONS & INFERENCES

Serum cytokines are elevated in IBS patients compared to HS. Immune activation characterizes a subset of patients, but modest associations between cytokine profile and symptoms suggest immune activity does not directly influence symptoms in IBS.

Sex-Gender Differences in Irritable Bowel Syndrome

Because of the sex-gender differences that are shown in a diversity of physiological and psychological factors, it can be speculated that the clinical presentation of symptoms as well as treatment strategies in women and men with irritable bowel syndrome (IBS) may differ. Studies have revealed that IBS is more common in women than men. As for the IBS subtype, IBS with constipation is significantly more prevalent among women than men. Sex hormones and gender differences may play important roles in the pathophysiology of IBS. However, its pathophysiologic mechanisms still remain largely unknown, and therapeutic implications are limited. Moreover, women IBS patients have been reported to feel more fatigue, depression, anxiety, and lower quality of life than men IBS patients. Furthermore, there has been evidence of differences in the appropriate treatment efficacy to IBS in men and women, although relatively few men are enrolled in most relevant clinical trials. A more sex-gender-oriented approach in the medical care setting could improve understanding of heterogeneous patients suffering from IBS. An individualized and multicomponent approach including sex and gender issues might help improve the treatment of IBS.

Heart rate variability characteristics of patients with irritable bowel syndrome and associations with symptoms

BACKGROUND

Disturbed brain-gut interactions are assumed to be of importance for symptom generation in patients with irritable bowel syndrome (IBS). The autonomic nervous system (ANS) is part of the bidirectional brain-gut communication, but previous studies in IBS show diverging results. We aimed to identify subgroups of IBS patients with distinct ANS characteristics differentiating them from healthy controls (HC), and to study associations between ANS status and symptoms.

METHODS

Heart rate variability (HRV) was measured in IBS patients and HC (Holter monitoring: supine and standing positions with controlled respiration and ambulatory 24-hour period). Frequency (5 minutes, supine, standing) and time domains (24 hours, day, night) were analyzed. Validated questionnaires were used to measure gastrointestinal and psychological symptoms in patients. Patients and HC were compared on a univariate and multivariate level (principal component analysis [PCA] and orthogonal partial least squares discriminatory analysis (OPLS-DA)).

KEY RESULTS

We analyzed 158 IBS patients (Rome III) and 39 HC. Patients differed significantly from HC in HRV parameters during daytime and in standing position. In the PCA, a majority of patients overlapped with HC, but the weighted means differed (P < .01). A subset of patients (n = 30; 19%) with an aberrant global HRV profile was identified through PCA and OPLS-DA; these patients reported more severe symptoms of frequent (P < .05) and loose stools (P = .03), as well as urgency (P = .01).

CONCLUSIONS AND INFERENCES

Altered ANS function was demonstrated in patients with IBS, and this might be of particular relevance for symptoms in a subset of the patients.

Are characteristics of abdominal pain helpful to identify patients with visceral hypersensitivity in irritable bowel syndrome? Results of a prospective study

BACKGROUND

Some consider that patients with visceral hypersensitivity may represent a separate entity within the IBS population not only from a pathophysiological but also from a clinical perspective. The aim of this prospective exploratory study was to assess whether characteristics of abdominal pain in IBS patients could be suggestive of hypersensitivity.

METHODS

This prospective study included consecutive IBS patients selected by Rome III criteria. Validated scores (IBS-SSS, Bristol stool scale, HADS) were used to phenotype patients who were also asked to describe the main location of their abdominal pain on a simple image (abdomen divided into 6 zones). Progressive isobaric rectal distensions were performed to demonstrate, with the ascending method of limits, allodynia (pain threshold lower than 24 mmHg).

KEY RESULTS

Fifty patients (women: 72%), 42.6 ± 15.7 years old, were included. Sub-types were IBS-D, IBS-C and IBS-M in 58%, 22% and 20% of cases, respectively. Allodynia was present in 18% of cases. Neither IBS-SSS nor intensity of pain was predictive of hypersensitivity. In hypersensitive patients, pain was more often located in one of the two iliac fossa (P = 0.02) and located outside these areas in only 11% of cases. The sensitivity and the specificity of this pain location to differentiate hyper from normosensitive patients were 0.89 and 0.59, respectively.

CONCLUSIONS & INFERENCES

The location of pain is different between hyper and normosensitive IBS patients. Pain located outside one of the two iliac fossa suggests that the patient is normosensitive.

Genetic studies in irritable bowel syndrome-status quo

AIM

To evaluate the most common studied genetic polymorphisms that may have an etiological role in irritable bowel syndrome (IBS).

METHODS

The data base PubMed was searched for studies analyzing the association between gene polymorphisms and IBS. All original full papers, written in English, were retained for further analysis. The retrieved papers were further systematized according to those polymorphisms that have been detected in IBS.

RESULTS

Considering these criteria, our literature search found 12 polymorphisms, residing in 10 genes, which were reported to be consistently associated with IBS. The initial search identified 189 articles, out of which 48 potentially appropriate articles were reviewed. Of these 48 articles, 41 articles were included in the review. These articles were published between 2002 and 2016. Out of these 41 studies, 17 reported analysis of the serotonin transporter (SERT) gene (SLC6A4), eight on guanine nucleotide-binding protein subunit beta-3 (GNbeta3), six on the serotonin type 3 receptor genes (HTR3A), four on (HTR3E), three on (HTR2A), three the tumor necrosis factor superfamily member TL1A gene (TNFSF15), and ten on genetic polymorphisms with limited evidence.

CONCLUSION

Current evidence for the relation between genetic polymorphisms and IBS is limited owing to the fact that high-quality prospective studies and detailed phenotyping of patients suffering from IBS and matched controls were lacking in the past.

Mixture model analysis identifies irritable bowel syndrome subgroups characterised by specific profiles of gastrointestinal, extraintestinal somatic and psychological symptoms

BACKGROUND

Current subgrouping of Irritable Bowel Syndrome (IBS) is exclusively based on stool consistency without considering other relevant gastrointestinal (GI), extraintestinal somatic or psychological features.

AIM

To identify subgroups based on a comprehensive set of IBS-related parameters.

METHODS

Mixture model analysis was used, with the following input variables: 13 single-item scores from the IBS-specific Gastrointestinal Symptom Rating Scale, average stool consistency and frequency from a 7-day Bristol Stool Form diary, 12 single-item extraintestinal symptom scores from the Patient Health Questionnaire-12, and anxiety and depression subscale scores from the Hospital Anxiety and Depression scale. The resulting latent subgroups were compared regarding symptom profiles using analysis of variance followed by pair-wise comparisons.

RESULTS

One hundred and seventy-two IBS patients (Rome III; 69% female; mean age 33.7 [range 18-60] years) were included. The optimal subgrouping showed six latent groups, characterised by: (I) constipation with low comorbidities, (II) constipation with high comorbidities, (III) diarrhoea with low comorbidities, (IV) diarrhoea and pain with high comorbidities, (V) mixed GI symptoms with high comorbidities, (VI) a mix of symptoms with overall mild severity. The subgroups showed differences in the distribution of Rome III-subtypes, IBS severity, presence of anxiety and depression, and gender, but not regarding age, IBS duration or reported post-infectious onset of IBS.

CONCLUSIONS

This model-based subgrouping of IBS partly supports the distinction of subgroups based on bowel habits, but additionally distinguishes subgroups with or without co-morbid extraintestinal somatic and psychological symptoms. The resulting groups show specific profiles of symptom combinations.