Development of Irritable Bowel Syndrome Features Over a 5-year Period

Exploring new subgroups for irritable bowel syndrome using a machine learning algorithm

Irritable bowel syndrome (IBS) is a complicated gut-brain axis disorder that has typically been classified into subgroups based on the major abnormal stool consistency and frequency. The presence of components other than lower gastrointestinal (GI) symptoms, such as psychological burden, has also been observed in IBS manifestations. The purpose of this research is to redefine IBS subgroups based on upper GI symptoms and psychological factors in addition to lower GI symptoms using an unsupervised machine learning algorithm. The clustering of 988 individuals who met the Rome III criteria for diagnosis of IBS was performed using a mixed-type data clustering algorithm. Nine sub-groups emerged from the proposed clustering: (I) High diarrhea, pain, and psychological burden, (II) High upper GI, moderate lower GI, and psychological burden, (III) High psychological burden and moderate overall GI, (IV) High constipation, moderate upper GI, and high psychological burden, (V) moderate constipation and low psychological burden, (VI) High diarrhea and moderate psychological burden, (VII) moderate diarrhea and low psychological burden, (VIII) Low overall GI, and psychological burden, (IX) Moderate lower GI, and low psychological burden. The proposed procedure led to the discovery of new homogeneous clusters in addition to certain well-known Rome sub-types for IBS.

Managing pain in irritable bowel syndrome: current perspectives and best practice

INTRODUCTION

Irritable bowel syndrome (IBS) is characterized by chronic symptoms (>6 months) of abdominal pain in combination with a disturbed bowel habit. There is an association between the intensity of abdominal pain and the need for health care utilization. A bidirectionally disordered gut-brain interaction is central in the pathophysiology of IBS where a number of factors, gastrointestinal and non-gastrointestinal, can contribute to the illness experience. In order to treat abdominal pain in IBS, mapping these factors in a multidimensional clinical profile is helpful.

AREAS COVERED

This review covers basic epidemiology and pathophysiology of abdominal pain in IBS, the diagnostic approach, and a multidimensional treatment model where the management of abdominal pain is in focus.

EXPERT OPINION

A personalized treatment of abdominal pain in IBS is possible in patients who understand the diagnosis, the potential of therapies used, and where a good continuity in the patient-doctor relationship is established.

Gastrointestinal-Specific symptom anxiety in patients with gastroparesis: Relationships to symptom severity and quality of life

BACKGROUND

Gastrointestinal (GI)-specific anxiety has been identified as a treatment target in irritable bowel syndrome. However, GI-specific anxiety has been understudied in other GI functional/motility disorders. Among adults with gastroparesis, we aimed to: (1) initially validate a measure of GI-specific anxiety, the Visceral Sensitivity Index (VSI); and (2) evaluate the relationship between GI-specific anxiety and gastroparesis symptom severity and quality of life, compared to measures of anxiety, depression, and somatization.

METHODS

Consecutive adult patients (N = 100) with gastroparesis presenting for initial consultation completed a series of self-report measures including the VSI. We conducted a confirmatory factor analysis of the VSI one-factor structure and tested internal consistency and convergent validity. We then performed hierarchical linear regression analyses to explore associations between VSI and gastroparesis symptom severity and overall quality of life.

KEY RESULTS

Confirmatory factor analysis revealed that the original VSI one-factor structure overall fit well [χ2 (90) = 220.1, p < 0.0001; SRMR = 0.08; RMSEA = 0.12; CFI = 0.96]. The VSI also had excellent internal consistency (α = 0.99) and convergent validity (r = 0.29-0.56; all p < 0.01). Higher GI-specific anxiety was significantly associated with greater gastroparesis symptom severity, including nausea/vomiting, fullness/satiety, and upper abdominal pain scores beyond depression, anxiety, or somatization (all p = <0.01-0.01). Additionally, higher GI-specific anxiety was significantly associated with lower mental health-related quality of life, beyond gastroparesis symptom severity, depression, anxiety, or somatization (p = 0.01).

CONCLUSIONS & INFERENCES

The VSI is an adequate measure of GI-specific anxiety in patients with gastroparesis. Higher GI-specific anxiety was associated with increased patient-reported gastroparesis symptom severity and decreased quality of life, beyond depression/anxiety.

Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a heterogeneous disorder of gut-brain interaction (DGBI) maintained by interacting biological, psychological, and social processes. Interestingly, there are two contrasting yet evidence-based treatment approaches for reducing IBS symptoms: exclusion diets such as those low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and exposure-based cognitive-behavioural therapy (CBT). Exclusion diets recommend patients avoid foods thought to be symptom-inducing, whereas exposure-based CBT encourages patients to expose themselves to foods.

AIMS

To address the paradox of conceptually opposite exclusion diets and exposure-based CBT for IBS.

METHODS

In this conceptual review, we describe the rationale, practical implementation, evidence base and strengths and weaknesses of each treatment. We conducted up-to-date literature search concerning the low FODMAP diet and CBT, and performed a secondary analysis of a previously conducted trial to illustrate a key point in our review.

RESULTS

The low FODMAP diet has demonstrated efficacy, but problems with adherence, nutritional compromise, and heightened gastrointestinal-specific anxiety raise caution. Exposure-based CBT has demonstrated efficacy with substantial evidence for gastrointestinal-specific anxiety as a key mechanism of action. Mediation analysis also showed that increased FODMAP intake mediated decreased symptom severity in exposure-based CBT. However, there is minimal evidence supporting which treatment "works best for whom" and how these approaches could be best integrated.

CONCLUSIONS

Even though exclusion diets and exposure-based CBT are conceptually opposite, they each have proven efficacy. Clinicians should familiarise themselves with both treatments. Further research is needed on predictors, mechanisms and moderators of treatment outcomes.

Quality of life in irritable bowel syndrome: Exploring mediating factors through structural equation modelling

BACKGROUND

Irritable Bowel Syndrome (IBS) negatively influences mental and physical quality of life (QoL), but factors that explain this impact are still unclear. Increasing evidence has associated IBS severity, psychological distress, somatic symptoms, and gastrointestinal (GI)-specific anxiety with QoL in IBS. The aim of this study is to further explore these associations and to analyze potential mediating factors.

METHOD

A total of 1017 IBS patients (69.3% female, mean age 40.6 years) who completed a QoL measure (SF-36) were included in this study. A proportion of these participants (N = 183; 72.7% female, mean age 41.7), who additionally completed psychological distress, somatic symptoms, and GI-specific anxiety measures, was included in the mediation analysis. This analysis was conducted via structural equation modelling to identify factors of importance for generic QoL, using a cross-sectional design.

RESULTS

IBS patients reported lower QoL than what is observed in the general population, in particular regarding role limitations caused by health and emotional functioning, vitality, and social functioning. Female patients scored lower than male patients on most QoL dimensions. The effects of IBS severity on mental and physical QoL were mediated by GI-specific anxiety. In addition to GI-specific anxiety, depressive symptoms were also of importance for mental QoL, and somatic symptom severity for physical QoL.

CONCLUSION

QoL is reduced in patients with IBS and GI-specific anxiety, depressive symptoms, and somatic complaints are particularly important for this outcome. Future trials should test the efficacy of psychological interventions specifically targeting these factors in improving QoL in IBS.

Irritable bowel syndrome: Factors of importance for disease-specific quality of life

BACKGROUND

Irritable bowel syndrome patients report reduced disease-specific quality of life (IBSQOL). Factors of potential relevance for QOL include gastrointestinal (GI), psychological, and somatic symptoms, demographics, and GI motor and sensory abnormalities.

OBJECTIVE

The aim of our study was to evaluate the relative importance of these factors on the different IBSQOL dimensions.

METHODS

We included irritable bowel syndrome (IBS) patients who completed validated questionnaires to assess QOL, stool form and frequency, GI symptom severity, psychological distress, GI-specific anxiety, sense of coherence, and overall somatic symptom severity. Patients also underwent tests for oroanal transit time and rectal sensitivity. The nine dimensions of IBSQOL and their average (overall IBSQOL) were used as outcome variables, and factors associated with these were assessed using general linear models.

RESULTS

We included 314 IBS patients (74% female, mean age 36.3 ± 12.2 years). Higher stool frequency, GI and overall somatic symptom severity, psychological distress, and GI-specific anxiety were independently associated with reduced overall IBSQOL, with the model explaining 60% of the variance (p < 0.001). In models using each of the nine dimensions as outcomes, different association of demographic factors, GI symptoms, overall somatic symptom severity, psychological factors and sense of coherence were associated with reduced IBSQOL, explaining 20%-60% of the variance, with GI-specific anxiety being the factor that contributed most frequently. Rectal sensitivity or oroanal transit time were not independently associated with any of the dimensions.

CONCLUSION

Different combinations of demographic factors, GI and somatic symptoms, and psychological factors are of importance for the nine IBSQOL dimensions. Gastrointestinal-specific anxiety was the most important factor contributing to the majority of those dimensions in patients with IBS.

Central sensitization and severity of gastrointestinal symptoms in irritable bowel syndrome, chronic pain syndromes, and inflammatory bowel disease

BACKGROUND

Central sensitization has been suggested as an explanation of the wide range of gastrointestinal and extraintestinal symptoms commonly seen in irritable bowel syndrome (IBS). In this study, the presence and level of central sensitization, and its association to gastrointestinal (GI) symptoms were explored in IBS in comparison with control groups.

METHODS

We investigated patients with IBS (n = 215), chronic pain disorders (n = 36), and inflammatory bowel disease (IBD) (n = 40) and volunteers without chronic diseases (n = 112). The Central Sensitization Inventory (CSI) was translated and validated in Swedish and used together with the Highly Sensitive Person (HSP) scale to measure the presence and level of central sensitization. Furthermore, severity of GI symptoms (GSRS-IBS and IBS-SSS), and anxiety and depression (HAD) were determined.

KEY RESULTS

The Swedish translation of CSI demonstrated excellent validity. Central sensitization, defined by validated cut-off levels for CSI and HSP, was common in the whole cohort (40% and 28%) and in IBS (57% and 35%). Study participants with central sensitization had more severe GI symptoms, anxiety and depression, than participants without central sensitization. Strong associations were seen between CSI and GI symptom severity in the whole cohort (GSRS-IBS: partial η²  = 0.455, p < 0.001; IBS-SSS: partial η²  = 0.408, p < 0.001), with decreasing strength in patients with chronic pain, IBD, IBS, and volunteers.

CONCLUSION AND INFERENCES

Central sensitization was common in IBS and associated with GI symptom severity, but with stronger associations in chronic pain disorders and IBD. This implies that other mechanisms may be of equal or greater importance for GI symptom severity in IBS.

Longitudinal follow-up of a novel classification system for irritable bowel syndrome: natural history and prognostic value

BACKGROUND

Conventionally, irritable bowel syndrome (IBS) is subgrouped using predominant stool form, yet it is a complex disorder, with multiple biopsychosocial contributors. We previously derived and validated a latent class model subgrouping people with IBS into seven clusters based on gastrointestinal and extraintestinal symptoms and psychological profile.

AIMS

To conduct longitudinal follow-up examining the natural history and prognostic value of these clusters.

METHODS

Participants completed a 12-month follow-up questionnaire. We applied our model to these data, comparing cluster membership between the two time points in those still meeting Rome IV criteria at follow-up, including stratifying the analysis by predominant stool pattern, and level of psychological burden, at baseline. We examined whether baseline cluster predicted the course of IBS, and whether starting new treatment was associated with changing cluster.

RESULTS

Eight hundred and eleven participants met Rome IV criteria for IBS at baseline, of whom 452 (55.7%) responded, and 319 (70.6%) still met Rome IV criteria for IBS at follow-up. Of these, 172 (53.9%) remained in the same IBS cluster as at baseline and 147 changed cluster. Cluster membership stratified according to psychological comorbidity was more stable; 84% of those in a cluster with high psychological burden at baseline remained in such a cluster at follow-up. People in clusters with high psychological burden at baseline had more severe symptoms (P < 0.001), received a higher mean number of subsequent treatments (P < 0.001), and were more likely to consult a doctor than people in clusters with low psychological burden (P < 0.001). There was no significant association between starting a new treatment and changing cluster at follow-up.

CONCLUSIONS

Longitudinal follow-up demonstrated little transition between clusters with respect to psychological burden, and these appeared to predict disease course. Directing treatment according to cluster, including earlier use of psychological therapies, and exploring how this approach influences outcomes in IBS, should be examined.

Cumulative Effect of Psychological Alterations on Gastrointestinal Symptom Severity in Irritable Bowel Syndrome

INTRODUCTION

Psychological alterations are common and considered important for symptom generation in irritable bowel syndrome (IBS). However, the possible cumulative effect of having multiple psychological alterations on gastrointestinal (GI) symptom severity in IBS is largely unknown.

METHODS

Patients with IBS (Rome IV) completed validated questionnaires assessing GI symptoms (Gastrointestinal Symptom Rating Scale, IBS version and IBS Severity Scoring System), personality traits (Big Five), posttraumatic stress and psychological alterations, anxiety (Generalized Anxiety Disorder 7-item scale and State-Trait Anxiety Inventory), depression (Patient Health Questionnaire, 9-item version), fatigue (Multidimensional Fatigue Inventory), pain catastrophizing, somatization (Patient Health Questionnaire, 12-item version), stress (Perceived Stress Scale), and GI-specific anxiety (Visceral Sensitivity Index). Of the 18 possible psychological factors, those with significant associations with GI symptom severity, corrected for multiple comparisons, were identified. The associations between increasing number of psychological alterations (validated cutoff values or uppermost tertile) and the severity of GI symptoms were analyzed with linear trend analyses.

RESULTS

In total, 106 patients with IBS (Rome IV criteria) were included (72 [68%] women, median age of 35 [interquartile range: 26-45] years). Psychological alterations were common and overlap among these factors were frequently seen. Five psychological factors (physical fatigue, GI-specific anxiety, perceived stress, pain catastrophizing, and trait anxiety) demonstrated significant, noncollinear associations with GI symptom severity. With increasing number of these psychological alterations, a gradual increase was seen in the overall severity of GI symptoms (Gastrointestinal Symptom Rating Scale, IBS version: partial η = 0.268, P < 0.001; IBS Severity Scoring System: partial η = 0.219, P < 0.001, both large effect sizes).

DISCUSSION

Distinct associations were seen between the severity of GI symptoms and individual, as well as an increasing number of psychological alterations. This highlights the importance of understanding different psychological alterations for the disease burden in IBS (visual abstract, Supplementary Digital Content 1, http://links.lww.com/AJG/B756).

Subtypes and Severity of Irritable Bowel Syndrome Are Not Related to Patients' Self-Reported Dietary Triggers: Results From an Online Survey in Dutch Adults

BACKGROUND

Diet plays an important role in symptom management of irritable bowel syndrome (IBS). However, current diet therapies are not optimal nor successful for everyone.

OBJECTIVE

To investigate whether subgroups based on IBS subtypes or severity identify different self-reported dietary triggers, and whether these are associated with severity and psychological factors.

DESIGN

Online cross-sectional survey PARTICIPANTS: Patients with IBS (n = 1601) who fulfilled the Rome IV criteria or had an IBS diagnosis.

MAIN OUTCOMES

Self-reported response to 44 preselected dietary triggers, IBS quality of life, and anxiety and depression. Subgroups were based on subtypes or severity.

STATISTICAL ANALYSIS

Response to dietary triggers was analyzed using multiple correspondence analysis. Moreover, a food score was calculated to quantify the number and severity of responses to dietary triggers.

RESULTS

Response to greasy foods, onions, cabbage, and spicy and fried foods were mentioned most often (ranging between 55% and 65%). Response to dietary triggers differed between subtypes and severity groups, but absolute differences were small. Multiple correspondence analysis did not reveal clustering between dietary triggers, and ellipses for the subtypes overlapped. Some clustering was seen when ellipses were drawn for severity, which indicates that severity explained a fraction of the variation in response to dietary triggers, and subtypes did not. The food score was not significantly different between subtypes but was significantly higher with higher levels of severity (mild = 20.9 ± 17, moderate = 29.2 ± 19, severe = 37.9 ± 20, P < .001), having depressive (no = 31.4 ± 20, yes = 37.4 ± 20, P < .001) or anxious symptoms (no = 30.7 ± 20, yes = 35.2 ± 20, P < .001), and lower quality of life (lower quality of life = 38.5 ± 19, higher quality of life = 26.5 ± 19, P < .001).

CONCLUSION

Patients with different IBS subtypes or IBS severity do not identify different self-reported dietary triggers. Patients with more severe IBS and who experience anxiety or depression tend to have severe responses to more dietary triggers. IBS severity seems a better classifier than Rome IV criteria regarding diet. Dietary treatment needs to be individualized under guidance of a dietitian.

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.

Food-symptom diaries can generate personalized lifestyle advice for managing gastrointestinal symptoms: A pilot study

BACKGROUND

Gastrointestinal (GI) symptoms have a heterogeneous pathophysiology. Yet, clinical management uses group-level strategies. There is a need for studies exploring personalized management options in patients with GI symptoms. From diaries of GI symptoms, food intake, and psychological distress, we extracted and validated personalized lifestyle advice. Secondly, we investigated group-level GI symptom triggers using meta-analysis.

METHODS

We collected 209 diaries of GI symptoms, food intake, and psychological distress, coming from 3 cohorts of patients with GI symptoms (n = 20, 26, and 163, median lengths 24, 17, and 38 days). Diaries were split into training and test data, analyzed, and the triggers emerging from the training data were tested in the test data. In addition, we did a random effects meta-analysis on the full data to establish the most common GI symptom triggers.

KEY RESULTS

Analysis of the training data allowed us to predict symptom triggers in the test data (r = 0.27, P < .001), especially in the subset of patients with a strong global association between lifestyle factors and symptoms (r = 0.45, P < .001). Low exposure to these triggers in the test data was associated with symptom reduction (P = .043). Meta-analysis showed that caloric intake in the late evening or night predicted an increase in GI symptoms, especially bloating. Several food-symptom associations were found, whereas psychological distress did not clearly lead to more severe GI symptoms.

CONCLUSIONS & INFERENCES

Diaries of GI symptoms, food intake, and psychological distress can lead to meaningful personalized lifestyle advice in subsets of patients.

Anxiety-related factors associated with symptom severity in irritable bowel syndrome

BACKGROUND

Gastrointestinal symptom-specific anxiety and somatization have both been associated with higher symptom severity in patients with irritable bowel syndrome (IBS); however, this relationship has not been explored fully. Moreover, the performance of the visceral sensitivity index (VSI) for measuring gastrointestinal symptom-specific anxiety has not been examined in a UK population. We conducted a cross-sectional survey to examine these issues.

METHODS

Gastrointestinal symptom-specific anxiety was measured using the VSI, and somatization was measured via the patient health questionnaire-12 (PHQ-12) in adults from the UK community with Rome IV-defined IBS. Exploratory factor analysis was performed on the VSI, prior to subsequent analyses, to establish its factor structure. Multiple regression analysis was used to determine the relationship between demographic features, different factors of the VSI, somatization, and IBS symptom severity.

KEY RESULTS

A total of 811 individuals with IBS provided complete data. Factor analysis of the VSI revealed a three-factor structure, accounting for 47% of the variance. The first of these VSI factors and the PHQ-12 were both strongly and independently associated with IBS symptom severity, for the group as a whole and for all four IBS subtypes. Most VSI items concerned with overt gastrointestinal symptom-specific anxiety loaded onto the other two VSI factors that were not associated with symptom severity.

CONCLUSIONS AND INFERENCES

The factor structure of the VSI requires further investigation. Our findings cast doubt on the central role of gastrointestinal symptom-specific anxiety as a driver for symptom severity in IBS. Awareness of both gastrointestinal and extra-intestinal symptoms, however, is strongly associated with symptom severity.

Review article: the incidence and risk factors for irritable bowel syndrome in population-based studies

BACKGROUND

In the absence of prior gastrointestinal infection, the risk factors for irritable bowel syndrome (IBS) are not well established.

AIM

To identify the incidence and risk factors for IBS in general population samples METHODS: Narrative review of population-based studies. Electronic databases were searched using the keywords "incidence," "onset," "epidemiology," "population," "risk factors" with "irritable bowel syndrome" with subsequent hand searching. Inclusion criteria were: population-based, adults, prospective design (including retrospective case cohorts), clinical or research diagnosis of IBS and exclusion of individuals who had IBS prior to recruitment.

RESULTS

Of 1963 papers, 38 were included; all provided data on risk factors, 27 reported incidence. The median incidence of physician-diagnosed IBS in 19 general population cohorts was 38.5 per 10 000 person-years (interquartile range = 20-45.3). In 14 cohorts with specific medical disorders, median incidence was 92 per 10 000 person-years (IQR: 73.9-119). Apart from gastroenteritis, the most common risk factors were other medical disorders, female sex, age (both young and old), anxiety and depression, life events/stress, frequent healthcare use, pain and sleep disorders. The results were conflicting for alcohol consumption, smoking and BMI. Incidence rates were similar in different countries but risk factors differed.

CONCLUSIONS

Incidence rates were generally lower than previous estimates reflecting physician-diagnosed IBS. The results highlight the importance of other medical and psychosocial problems in the onset of IBS in addition to prior gastrointestinal infections. Aetiological research could be enhanced by studying the underlying mechanisms relating to all of these risk factors.

Symptom-based latent classes of persons with irritable bowel syndrome

A large amount of interindividual variability exists in symptom experiences of persons with irritable bowel syndrome (IBS). Thus, consideration of multiple symptoms to identify distinct symptom subgroups may be useful in directing personalized health strategies for symptom management. We aimed to identify latent classes (i.e., subgroups) of persons with IBS who share similar patterns of symptoms using symptom-related variables (six groups of daily diary symptoms, cognitive beliefs about IBS, and IBS quality of life [QOL]); and to examine how subgroups differed in patient characteristics. Data were derived from a baseline assessment of men and women enrolled in two cognitively-focused intervention trials (N = 332). Using latent class analysis, four latent classes were identified: Class 1 (low symptoms and good QOL, n = 153), Class 2 (low symptoms and moderate QOL, n = 106), Class 3 (high symptoms with diarrhea and poor QOL, n = 38), and Class 4 (high symptoms with low diarrhea and moderate QOL, n = 35). Diarrhea, being female, less formal education, unemployment, and previous history of major depressive disorder were associated with membership in Class 3. Using these distinct symptom profiles, the next step is to explore underlying mechanisms accounting for symptom burden with the goal of designing tailored interventions to reduce that burden.

Reduction in IBS symptom severity is not paralleled by improvement in quality of life in patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a brain-gut disorder, of which the natural course varies between patients and is difficult to predict. This study aimed to evaluate symptom evolution over a 5-year follow-up period and to identify baseline predictors for symptom severity and quality of life (QoL) at follow-up.

METHODS

Maastricht IBS cohort participants completed questionnaires upon inclusion regarding demographics and lifestyle, gastrointestinal (GI) symptoms, anxiety and depression, and QoL. The same questionnaires, in addition to others, were completed after 5 years. Rome criteria were confirmed face-to-face at initial enrollment and through telephonic interviews at follow-up.

KEY RESULTS

At a mean follow-up of 4.7 years, 379 patients were approached of whom 203 (53.7%) responded. Of these, 161 were reached by telephone and analyzed; 49 (30.4%) did not fulfill the Rome III criteria at follow-up and had lower levels of GI symptoms and GI-specific anxiety compared to those remaining Rome III-positive (P < 0.001). However, Rome III-negative patients had comparable levels of QoL and life satisfaction, comorbid anxiety and depression, work absenteeism, and impaired productivity. No baseline predictors were found for being Rome III-positive or Rome III-negative. However, greater age and lower baseline physical QoL predicted lower physical QoL at follow-up (P < 0.005 and P < 0.01, respectively), while lower baseline mental QoL predicted lower mental QoL at follow-up (P = 0.005). Additionally, higher anxiety and depression scores at follow-up were associated with lower QoL and life satisfaction at follow-up (P < 0.001).

CONCLUSIONS AND INFERENCES

Long-term QoL and general well-being might depend on concurrent psychological symptoms, rather than GI symptom improvement.

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.

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.