Trastornos funcionales y motores digestivos

We summarize and discuss the studies presented at the congress of the American Association of Gastroenterology (Digestive Disease Week) that, in our opinion, are of greatest interest. Both clinically and physiopathologically, functional gastrointestinal (GI) disorders are highly complex. A single cause is unlikely to explain symptoms as heterogeneous as those of functional dyspepsia and irritable bowel syndrome (IBS). Therefore, it is easier (and more useful) to try to understand functional GI disorders using a bio-psycho-social model. Moreover, data supporting the combined importance of genetic, organic and psychological factors in the onset and persistence of functional GI disorders are increasingly convincing. This year, new data have been provided on pharmacogenetics in gastroparesis, on microinflammation or alterations in the modulation of somatic and visceral sensitivity in functional dyspepsia, and on the impact of psychological factors in IBS. From the therapeutic point of view, further information has been provided on the role of probiotics, the antinociceptive effect of linaclotide (demonstrated in several studies presented this year), and on the high efficacy of hypnotherapy in patients with IBS. Finally, data on the clinical management of patients with constipation due to pelvic floor dyssynergia and on the safety and efficacy of prucalopride in patients with severe constipation were also of interest.     

Psychosocial factors are linked to functional gastrointestinal disorders: a population based nested case-control study

BACKGROUND: It is widely accepted based on volunteer studies that levels of psychological distress are similar in those with functional gastrointestinal (GI) disorders and health in the community, while increased psychological distress in outpatients is largely explained by health-care seeking. AIMS: To determine if psychological distress, life event stress, or social support is associated with functional GI disorders in a population-based study. METHODS: A nested case-control study was performed by first mailing a self-report bowel disease questionnaire to a random sample of Olmsted County, Minnesota, aged 20-50 yr. All persons who reported symptoms of nonulcer dyspepsia (NUD) or irritable bowel syndrome (IBS) (cases), or an absence of GI symptoms (controls), were invited to complete a series of validated questionnaires designed to measure psychological distress, life event stress, social support, current symptoms, and physician visits. RESULTS: 103 subjects with functional GI disorders and 119 controls participated (85% of eligible). Functional GI disorders were more likely to be reported by those with higher scores on each of the nine SCL-90-R scales used to measure psychological distress (except phobic anxiety), and those with more negative and total life event stress. In a multiple logistic regression model (including age and gender), somatization, interpersonal sensitivity, and total life event stress were independently associated with functional GI disorders. Findings were similar when subjects with the IBS and NUD were analyzed separately compared to controls. CONCLUSIONS: Contrary to current dogma, psychosocial factors were significantly associated with functional GI disorders in this community sample. This suggests that these factors may be involved in the etiopathogenesis rather than just driving health-care utilization.     

Prevalence of functional gastrointestinal disorders in a population of subjects consulting for gastroesophageal reflux disease in general practice

AIMS: To establish the prevalence of functional gastrointestinal (GI) disorders in adult patients with symptoms of gastroesophageal reflux disease (GERD) and to assess the impact of GERD treatment on functional GI disorders in medical practice in France. METHODS: 3318 patients with GERD symptoms (mean age 53 yr; 1726 women and 1592 men) were involved in the survey. A questionnaire on demographic data, GERD features, presence of functional GI disorders and their features, and impact of GERD treatment on functional GI disorders was performed by the physician. The size of the different groups was compared using either a chi2 test or a Mantel-Haenszel analysis, on a case by case basis. RESULTS: Seventy-two percent of patients with GERD had associated functional GI disorders, with a mean of 4.1 +/- 1.9 functional digestive symptoms per patient. Gas, flatulence, transit disorders and abdominal distension were the most commonly reported symptoms. Among patients with functional GI symptoms, 27% had symptoms suggestive of irritable bowel syndrome (IBS), 16% were suggestive of dyspepsia while 57% had both upper and lower functional digestive symptoms. According to the patients, GERD treatment had a positive impact (significant to complete improvement) on their functional GI disorders in about one-third of patients particularly in those with dyspeptic-type symptoms. CONCLUSIONS: Functional GI disorders are particularly common in adult patients suffering from GERD, with a three times higher prevalence than in the general population.     

When is irritable bowel syndrome not irritable bowel syndrome? Diagnosis and treatment of chronic functional abdominal pain

Functional abdominal pain syndrome (FAPS) is a distinct chronic gastrointestinal (GI) pain disorder characterized by the presence of constant or frequently recurring abdominal pain that is not associated with eating, change in bowel habits, or menstrual periods. The pain experience in FAPS is predominantly centrally driven as compared to other chronic painful GI conditions such as inflammatory bowel disease and chronic pancreatitis where peripherally acting factors play a major role in driving the pain. Psychosocial factors are often integrally associated with the disorder and can pose significant challenges to evaluation and treatment. Patients suffer from considerable loss of function, which can drive health care utilization. Treatment options are limited at best with most therapeutic regimens extrapolated from pain management of other functional GI disorders and chronic pain conditions. A comprehensive approach to management using a biopsychosocial construct and collaboration with pain specialists and psychiatry is most beneficial to the management of this disorder.     

Role of stress in functional gastrointestinal disorders. Evidence for stress-induced alterations in gastrointestinal motility and sensitivity.

Psychological stress is widely believed to play a major role in functional gastrointestinal (GI) disorders, especially irritable bowel syndrome (IBS), by precipitating exacerbation of symptoms. The available data clearly demonstrate that inhibition of gastric emptying and stimulation of colonic transit is the most consistent pattern in the motility response of the GI tract to acute or short-term stress. Thus, one might propose that these alterations might play a pathophysiological role in dyspeptic symptoms and alterations in stool frequency and consistency in patients with stress-related functional GI disorders. Taken together, the above-mentioned studies suggest that the colonic motor response to stress is exaggerated in IBS. There is evidence that an increased emotional response is associated with this difference in colonic, and perhaps also gastric motor responses to certain stressors. However, almost no valid data are available so far from human studies addressing the question if differences in motility responses to stress between patients with functional GI disorders and healthy subjects are due to an altered stress response associated with an imbalance of the autonomic nervous system or increased stress susceptibility. We can summarize that in experimental animals the most consistent pattern of GI motor alterations induced by various psychological and physical stressors is that of delaying gastric emptying and accelerating colonic transit. Endogenous corticotropin-releasing factor (CRF) in the brain plays a significant role in the central nervous system mediation of stress-induced inhibition of upper GI and stimulation of lower GI motor function through activation of brain CRF receptors. The inhibition of gastric emptying by CRF may be mediated by interaction with the CRF-2 receptor, while CRF-1 receptors are involved in the colonic and anxiogenic responses to stress. Endogenous serotonin, peripherally released in response to stress, seems to be involved in stress- and central CRF-induced stimulation of colonic motility by acting on 5HT-3 receptors. Taken together, the limited data available from investigations in healthy subjects and patients with functional GI disorders provide some evidence that stress affects visceral sensitivity in humans. Acute psychological stress seems to facilitate increased sensitivity to experimental visceral stimuli, if the stressor induces a significant emotional change. In summary, studies in experimental animals suggest that stress-induced visceral hypersensitivity is centrally mediated by endogenous CRF and involvement of structures of the emotional motor system, e.g. the amygdala. Stress-induced activation or sensitization of mucosal mast cells in the GI tract seem to be involved in stress-associated alterations of visceral sensitivity.     

Spectrum of Gastrointestinal Manifestations in Joint Hypermobility Syndromes

Joint hypermobility is a common, primarily benign finding in the general population. However, in a subset of individuals joint hypermobility causes a range of clinical problems mainly affecting the musculoskeletal system and, to a lesser extent, extra-articular disorders. Joint hypermobility often appears as a familial trait and is shared by several inherited connective tissue disorders, including the hypermobility subtype of Ehlers-Danlos syndrome (hEDS) and benign joint hypermobility syndrome (BJHS/JHS). Although joint hypermobility has primarily been thought of as a rheumatological disorder, increasing evidence shows significant associations between both hEDS and BJHS with specific extra-articular disorders. To date, the strongest associations of these 2 conditions are with anxiety disorders, orthostatic tachycardia, various functional gastrointestinal (GI) disorders and pelvic and bladder dysfunction. This review article focuses on GI disorders associated with both hEDS and BJHS. The aim of this review is to evaluate existing research and literature regarding associations between JHS (hEDS/BJHS) and GI disorders. Our goal is to raise awareness of BJHS/JHS and hEDS as an explanation for chronic unexplained symptoms and functional GI disorders as well as to review the current standard tests available for proper evaluation of GI symptoms in these patients.     

New directions in brain imaging research in functional gastrointestinal disorders

Functional brain imaging has greatly enhanced the ability to investigate brain-gut interactions and to assess the central nervous system role on visceral pain perception. The results of studies using brain imaging in irritable bowel syndrome (IBS) have demonstrated differences in brain activation between patients with IBS and healthy controls. In addition, the more recent studies are starting to shed light on pathophysiological mechanisms that underlie the generation of functional gastrointestinal (GI) symptoms as well as the response to treatment. These studies highlight the potential of functional brain imaging to become an important and exciting investigative tool in research of functional GI disorders. However, the multifactorial, multideterminant nature of these disorders, the current limitations in the understanding of the pathophysiology of the disorders, and the heterogeneous patient population make brain imaging research in this field difficult and require caution in the interpretation of the data. The continued development of brain imaging techniques provides not only exciting opportunities but also significant challenges to the field. This article focuses on brain imaging research in functional GI disorders. It describes some of the recent developments in the use of brain imaging in research of the brain-gut axis and provides an overview of the current data.     

Validation of Rome II criteria for functional gastrointestinal disorders by factor analysis of symptoms in Asian patient sample

BACKGROUND: It has been unclear as to whether the Rome II criteria could be applied to patients in the Asia region with functional gastrointestinal (GI) diseases. The aim of the present study was to determine if symptoms of Asian patients with functional gastrointestinal disorders formed groups which corresponded to the Rome II diagnostic criteria. METHODS: A modified English version of Talley's bowel disease questionnaire was developed in collaboration with various research teams in accordance with the Rome II criteria. This instrument was translated into the local languages of the following nine Asian regions: China, Hong Kong, Indonesia, Korea, Malaysia, Singapore, Taiwan, Thailand and Vietnam. From September to December 2001, newly enrolled outpatients attending 14 GI or medical clinics in these regions were invited to complete the questionnaire. From these respondents, patients with functional gastrointestinal disorders fulfilling the '12 weeks out of 12 months' criteria were separated for further analysis. Principal component factor analysis with varimax rotation was used to identify symptom clusters or factors. These factors were compared with the existing classification of functional GI diseases derived from the Rome II criteria. RESULTS: Factor analysis of symptoms from 1012 functional GI patients supported the Rome II classification of the following groups of functional GI disorders: diarrhea-predominant irritable bowel syndrome, functional constipation, functional dyspepsia, functional abdominal pain syndrome, functional heartburn, and functional vomiting. Functional diarrhea was combined with functional anorectal disorders, and globus merged with functional dysphagia into one factor. Some of the functional dyspepsia, abdominal bloating and belching symptoms were loaded into one factor. CONCLUSIONS: Factor analysis of symptoms from a sample of Asian patients with functional GI disorders partially supported the use of the Rome II classification.     

Role of Ghrelin in the Pathophysiology of Gastrointestinal Disease

Ghrelin is a 28-amino-acid peptide that plays multiple roles in humans and other mammals. The functions of ghrelin include food intake regulation, gastrointestinal (GI) motility, and acid secretion by the GI tract. Many GI disorders involving infection, inflammation, and malignancy are also correlated with altered ghrelin production and secretion. Although suppressed ghrelin responses have already been observed in various GI disorders, such as chronic gastritis, Helicobacter pylori infection, irritable bowel syndrome, functional dyspepsia, and cachexia, elevated ghrelin responses have also been reported in celiac disease and inflammatory bowel disease. Moreover, we recently reported that decreased fasting and postprandial ghrelin levels were observed in female patients with functional dyspepsia compared with healthy subjects. These alterations of ghrelin responses were significantly correlated with meal-related symptoms (bloating and early satiation) in female functional dyspepsia patients. We therefore support the notion that abnormal ghrelin responses may play important roles in various GI disorders. Furthermore, human clinical trials and animal studies involving the administration of ghrelin or its receptor agonists have shown promising improvements in gastroparesis, anorexia, and cancer. This review summarizes the impact of ghrelin, its family of peptides, and its receptors on GI diseases and proposes ghrelin modulation as a potential therapy.     

Post-infectious functional gastrointestinal disorders: from the acute episode to chronicity

Functional gastrointestinal disorders (FGID) form a major part of gastroenterology practice. Several studies have reported the development of post-infectious irritable bowel syndrome (PI-IBS) after acute gastroenteritis (AGE). Non-gastrointestinal (GI) infections may increase the risk of developing IBS. There are also data showing that a GI infection may trigger functional dyspepsia (PI-FD). The possible development of PI-IBS or PI-FD depends on factors related to both the infection and the host. Microinflammation has been found in patients with post-infectious FGID. Studies performed in animal models show that infection and acute inflammation permanently change gastrointestinal motility and sensitivity. The role of AGE in the development of FGID is important not only because this entity provides an excellent natural model for pathogenic study but also because it provides an opportunity for preventive action.     

Trastornos funcionales digestivos post-infecciosos: del episodio agudo a la molestia crónica

Functional gastrointestinal disorders (FGID) form a major part of gastroenterology practice. Several studies have reported the development of post-infectious irritable bowel syndrome (PI-IBS) after acute gastroenteritis (AGE). Non-gastrointestinal (GI) infections may increase the risk of developing IBS. There are also data showing that a GI infection may trigger functional dyspepsia (PI-FD). The possible development of PI-IBS or PI-FD depends on factors related to both the infection and the host. Microinflammation has been found in patients with post-infectious FGID. Studies performed in animal models show that infection and acute inflammation permanently change gastrointestinal motility and sensitivity. The role of AGE in the development of FGID is important not only because this entity provides an excellent natural model for pathogenic study but also because it provides an opportunity for preventive action.     

The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions

Functional gastrointestinal disorders (FGIDs), characterized by chronic abdominal complaints without a structural or biochemical cause, are common diseases that are frequently encountered by specialists in internal medicine. Collectively, irritable bowel syndrome (IBS) and functional dyspepsia are estimated to affect up to 22% of the population, and are often associated with additional somatic and pain complaints, all without an obvious structural source [1,2]. An appreciation of the current understanding of the mechanistic basis for these disorders is key to developing treatment goals and optimization of patient management strategies. In recent years, the brain-gut axis increasingly has been recognized as a central factor in the experience of functional abdominal pain disorders, including the most recent Rome IV guidelines which identify FGIDs as disorders of gut-brain interaction [3]. The brain-gut axis (BGA), simply defined, is a complex network of bidirectional communication between the central and enteric nervous systems. This axis broadly includes all the systems involved with communication between the GI tract and central nervous system (CNS), with principle inputs into this network occurring between the CNS, enteric nervous system (ENS), and autonomic nervous systems (ANS), but also includes interfaces with numerous other factors, including endocrine hormones and immune effector cells as well as interactions with the gut microbiota. Perturbances to this system have been found to play a critical role in the development of visceral hypersensitivity, bowel dysregulation, and mood. This review will summarize the principle processes involved in the neurologic and biologic function of the brain-gut axis, our current understanding of its role in functional GI disorders, and potential targets for therapeutic intervention.     

Functional and motility gastrointestinal disorders

As in previous years, a huge number of studies were presented at the Congress of the American Gastroenterology Association (Digestive Diseases Week [DDW]), some of which were better than others. The present article attempts to extract and summarize the most interesting findings reported. In general terms, certain technological advances have been consolidated, with full incorporation into clinical practice, such as impedancemetry and high-resolution manometry. New physiopathological data are coming to light that increasingly indicate the inextricable link between organic and psychological factors (the biopsychosocial model) in functional gastrointestinal disorders (FGID). Despite the high hopes that the Rome III criteria would improve the diagnosis of FGID and especially that of functional dyspepsia, their practical application has been fairly discouraging. Moreover, at least two studies have demonstrated that these criteria cannot be used to differentiate subtypes of functional dyspepsia and that there is wide overlap with gastroesophageal reflux disease. New data were presented on the role of genetic, microinflammatory and psychological factors in the etiopathogenesis of the two main FGID: functional dyspepsia and irritable bowel syndrome (IBS). The results on the safety and efficacy of acotiamide in functional dyspepsia and of linaclotide and prucalopride in idiopathic and IBS-associated constipation were also presented. Several studies, and even meta-analyses, have demonstrated the utility of biofeedback in the treatment of constipation. Even so, the efficacy of this therapy has been questioned due to certain methodological deficiencies in some studies. In DDW 2011, studies confirming the utility of biofeedback, whether hospital- or home-based were presented, in dyssynergy constipation. The present article also mentions certain features of special interest in the diagnosis and treatment of rumination syndrome, thoracic pain of possible esophageal origin and cannabinoid-induced hyperemesis syndrome.     

Health-related quality of life in patients attending a gastroenterology outpatient clinic: functional disorders versus organic diseases.

BACKGROUND & AIMS: Several gastrointestinal (GI) disorders have major effects on health-related quality of life (HRQOL), but there are few direct comparisons between functional GI disorders and organic GI diseases. This study aimed to compare HRQOL between these 2 groups and to assess factors of importance for HRQOL. METHODS: Three hundred ninety-nine consecutive patients attending a GI outpatient clinic completed HRQOL instruments (Short Form 36 [SF-36] and Psychological General Well-Being index [PGWB]) and the Gastrointestinal Symptom Rating Scale (GSRS). For the analyses we divided the patients into 2 diagnostic groups: functional GI disorders (n = 112) and organic GI diseases (n = 287). RESULTS: Compared with norm values on SF-36 and PGWB, both patient groups exhibited profound reductions in HRQOL. After correcting for age, gender, and disease duration, patients with a functional GI disorder had significantly lower scores than patients with an organic GI disease on 6 of 8 SF-36 domains and 5 of 6 PGWB domains. Vitality and anxiety on PGWB, abdominal pain and diarrhea on GSRS, age, and gender independently contributed to the physical component score of SF-36 (adjusted R(2) = 32%). Patients with a functional GI disorder had more severe reflux, abdominal pain, constipation, and indigestion, but the severity of diarrhea did not differ between the groups. HRQOL was reduced with increasing severity of GI symptoms. CONCLUSION: GI disorders have profound effects on HRQOL, and the impact is greater in patients with functional GI disorders as compared with organic GI diseases. The reduction in HRQOL is associated with the severity of both psychological and GI symptoms.     

Functional Abdominal Pain

Functional abdominal pain syndrome (FAPS) is a relatively less common functional gastrointestinal (GI) disorder defined by the presence of constant or frequently recurring abdominal pain that is not associated with eating, change in bowel habits, or menstrual periods (Drossman Gastroenterology 130:1377–1390, 2006), which points to a more centrally targeted (spinal and supraspinal) basis for the symptoms. However, FAPS is frequently confused with irritable bowel syndrome and other functional GI disorders in which abdominal pain is associated with eating and bowel movements. FAPS also differs from chronic abdominal pain associated with entities such as chronic pancreatitis or chronic inflammatory bowel disease, in which the pain is associated with peripherally acting factors (eg, gut inflammation or injury). Given the central contribution to the pain experience, concomitant psychosocial disturbances are common and strongly influence the clinical expression of FAPS, which also by definition is associated with loss of daily functioning. These factors make it critical to use a biopsychosocial construct to understand and manage FAPS, because gut-directed treatments are usually not successful in managing this condition.     

Acupuncture for functional gastrointestinal disorders

Functional gastrointestinal (GI) symptoms are common in the general population. Especially, motor dysfunction of the GI tract and visceral hypersensitivity are important. Acupuncture has been used to treat GI symptoms in China for thousands of years. It is conceivable that acupuncture may be effective in patients with functional GI disorders because it has been shown to alter acid secretion, GI motility, and visceral pain. Acupuncture at the lower limbs (ST-36) causes muscle contractions via the somatoparasympathetic pathway, while at the upper abdomen (CV-12) it causes muscle relaxation via the somatosympathetic pathway. In some patients with gastroesophageal reflux disease (GERD) and functional dyspepsia (FD), peristalsis and gastric motility are impaired. The stimulatory effects of acupuncture at ST-36 on GI motility may be beneficial to patients with GERD or FD, as well as to those with constipation-predominant irritable bowel syndrome (IBS), who show delayed colonic transit. In contrast, the inhibitory effects of acupuncture at CV-12 on GI motility may be beneficial to patients with diarrhea-predominant IBS, because enhanced colonic motility and accelerated colonic transit are reported in such patients. Acupuncture at CV-12 may inhibit gastric acid secretion via the somatosympathetic pathway. Thus, acupuncture may be beneficial to GERD patients. The antiemetic effects of acupuncture at PC-6 (wrist) may be beneficial to patients with FD, whereas the antinociceptive effects of acupuncture at PC-6 and ST-36 may be beneficial to patients with visceral hypersensitivity. In the future, it is expected that acupuncture will be used in the treatment of patients with functional GI disorders.     

Role of environmental pollution in irritable bowel syndrome

Irritable bowel syndrome (IBS), with the prevalence of 10%-20 % of the population has become an emerging problem worldwide. IBS is a functional gastrointestinal (GI) disorder characterized by abdominal pain or discomfort and altered bowel habits. The etiology of IBS contains genetic, psychological, and immunological factors, and has not been fully elucidated; of note, recent studies also point at environmental pollution and its role in the development of functional GI diseases. In this review we focus on several environmental factors, such as bacterial contamination, air pollution, radiation and even stress as potential triggers of IBS. We discuss associated disturbances in homeostasis, such as changes in intestinal microbiome and related pathophysiological mechanisms. Based on the effect of environmental factors on the GI tract, we also propose novel targets in IBS treatment.     

Electrical therapies for gastrointestinal motility disorders

Introduction: Gastrointestinal (GI) motility disorders are common in clinical settings, including esophageal motility disorders, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, chronic intestinal pseudo-obstruction, post-operative ileus, irritable bowel syndrome, diarrhea and constipation. While a number of drugs have been developed for treating GI motility disorders, few are currently available. Emerging electrical stimulation methods may provide new treatment options for these GI motility disorders.

Areas covered: This review gives an overview of electrical therapies that have been, and are being developed for GI motility disorders, including gastroesophageal reflux, functional dyspepsia, gastroparesis, intestinal motility disorders and constipation. Various methods of gastrointestinal electrical stimulation are introduced. A few methods of nerve stimulation have also been described, including spinal cord stimulation and sacral nerve stimulation. Potentials of electrical therapies for obesity are also discussed. PubMed was searched using keywords and their combinations: electrical stimulation, spinal cord stimulation, sacral nerve stimulation, gastrointestinal motility and functional gastrointestinal diseases.

Expert commentary: Electrical stimulation is an area of great interest and has potential for treating GI motility disorders. However, further development in technologies (devices suitable for GI stimulation) and extensive clinical research are needed to advance the field and bring electrical therapies to bedside.     

Trastornos funcionales y motores digestivos

This article discusses the most interesting studies on functional and motility gastrointestinal disorders presented in Digestive Diseases Week (DDW) in 2013. New data were reported on the clinical importance of functional gastrointestinal disorders (FGID) and on how they can produce numerous disturbances such as inflammatory bowel disease. These disturbances are associated with somatic functional disease and particularly with fatigue. In addition, new data have emerged on the physiopathology of these disorders, with some studies reporting that environmental factors and events in early infancy can favor their development. Data were also presented on how bile acids can increase susceptibility to diarrhea in patients with irritable bowel syndrome (IBS) and on how the type of food intake can favor the development of symptoms. More data are available on the presence of underlying celiac disease in patients with IBS, which should prompt us to investigate this disease in our patients. Likewise, indiscriminate application of a gluten-free diet in patients with IBS has been shown not to produce a clear improvement. Regarding the physiopathology of functional dyspepsia (FD), results have been presented on how psychological factors can modify gastric accommodation and how this is in turn related to visceral hypersensitivity and gastric emptying. Regarding therapy, mirtazapine can improve symptoms and lead to weight gain in patients with severe FD and substantial weight loss. Results were presented on new drugs for IBS such as ibodutant and on old drugs with new applications such as mesalazine and ebastine. The antinociceptive effect of linaclotide is now better understood and a meta-analysis has shown its effectiveness in IBS with constipation as the main symptom. In patients with constipation, pelvic floor dysynergy can be diagnosed by a simple clinical interview and rectal touch. More data are available on the efficacy of prucalopride (which has been shown to accelerate colon transit time) and data were provided on plecanatide, a potential new drug that could be useful in constipation. Finally, results were presented on the use of botulinum toxin injection in patients with spastic motility disorders of the esophagus. Also worthy of mention is a study confirming a higher frequency of esophageal cancer patients with achalasia who receive treatment.     

Gastrointestinal symptoms and subjects cluster into distinct upper and lower groupings in the community: a four nations study

OBJECTIVE: It is unknown whether distinct functional GI (GI) symptom groupings occur in the general population and whether these are similar across different cultures. Although symptom-based diagnostic criteria have been developed for upper and lower GI syndromes (the Rome criteria), the classification is controversial. We aimed to identify whether independent symptom-based subgroups exist in four countries consistent with the Rome criteria. METHODS: Random samples of the community were mailed a validated questionnaire based on the Bowel Disease Questionnaire in Rochester, MN (n = 2,220), in Sydney, Australia (n = 1,135), and in Essen, Germany (n = 500). A different validated questionnaire was mailed to a random sample in Osthammar, Sweden (n = 1,517). Only the common questions (n = 22) were used in the current analysis, and these were essentially identical in wording. The underlying structure of the item responses was examined using factor analysis. Initial factors were extracted using principal components analysis and then rotated using Varimax. Clustering of symptoms among individuals was examined though cluster analysis, using the factors as the basis for clustering. RESULTS: Response rates varied from 64% to 80%; responders and nonresponders were similar sociodemographically. All four studies yielded similar factor structures. All countries reported symptom groupings consistent with the irritable bowel syndrome (IBS), dyspepsia and/or gastroesophageal reflux, and constipation; all except Sweden also had a diarrhea group. The cluster analysis yielded slightly more disparate results but a healthy group was present in all populations. All four populations had an IBS and/or bowel dysfunction cluster identified; a gastroesophageal reflux cluster was also present in all countries. CONCLUSIONS: The similarity of factor and cluster structures found in these four nations suggest that patterns of GI symptoms and groupings of individuals are similar across these Western cultures. These results are consistent with the current international Rome classification for separate upper and lower functional GI disorders.