Prevalence of irritable bowel syndrome according to different diagnostic criteria in a non-selected adult population

BACKGROUND: Prevalence of irritable bowel syndrome shows great variation among epidemiological studies, which may be due to different diagnostic criteria. AIM: To assess prevalence of irritable bowel syndrome according to various diagnostic criteria and to study differences in symptom severity, psychopathology, and use of health care resources between subjects fulfilling different diagnostic criteria. METHODS: A questionnaire was mailed to 5000 randomly selected adults. Presence of irritable bowel syndrome was assessed by four diagnostic criteria: Manning 2 (at least two Manning symptoms), Manning 3 (at least three Manning symptoms), Rome I and Rome II. RESULTS: Response rate was 73%. Prevalence of irritable bowel syndrome by Manning 2, Manning 3, Rome I and Rome II criteria was 16.2%, 9.7%, 5.6%, and 5.1% respectively. Of those fulfilling Rome II criteria, 97% fulfilled Manning 2. Severe or very severe abdominal pain was reported by 27-30% of Manning-positive subjects, and 44% of Rome-positives. Prevalence of depression in Manning 2, and Rome II groups was 30.6 and 39.3%. CONCLUSIONS: Prevalence of irritable bowel syndrome by Rome II criteria is considerably lower than by Manning criteria. Subjects fulfilling Rome criteria form a subgroup of Manning-positive subjects with more severe abdominal symptoms, more psychopathology, and more frequent use of the health care system.     

Stability of irritable bowel syndrome using a Rome II-based classification

BACKGROUND: As there is no biological marker for irritable bowel syndrome, a diagnosis is made using symptom-based criteria. AIM: To evaluate the stability of self-reported symptoms consistent with Rome II-based irritable bowel syndrome classification. METHODS: Irritable bowel syndrome subjects identified in a 2001 population-based study by modified Rome II criteria were re-contacted 2 years later. Data were collected via a web-based questionnaire. RESULTS: Of the 697 subjects, 30% remained in the same irritable bowel syndrome subtype in both surveys, 18.4% changed irritable bowel syndrome subtype and 52% no longer met the irritable bowel syndrome criteria at follow-up. Subjects continuing to meet the irritable bowel syndrome criteria were more likely to have been initially classified in the alternating irritable bowel syndrome subtype and had more psychological impairment and lower irritable bowel syndrome-related quality of life than subjects not fulfilling the irritable bowel syndrome criteria at follow-up. Lack of pain caused more subjects to fall out of the irritable bowel syndrome criteria than the absence of non-painful bowel symptoms. However, the majority of subjects that did not fulfill the pain component of the irritable bowel syndrome criteria continued to report abdominal pain of at least moderate severity. CONCLUSION: In a US population-based follow-up study using modified Rome II criteria, we found irritable bowel syndrome is episodic in nature and current classification is limited in capturing fluctuation of disease over time.     

Irritable bowel, smoking and oesophageal acid exposure: an insight into the nature of symptoms of gastro-oesophageal reflux

BACKGROUND: In gastro-oesophageal reflux disease, oesophageal acid exposure correlates with symptoms but explains only a small fraction of their variance. AIMS: To elucidate the effects of irritable bowel syndrome and smoking on gastro-oesophageal reflux disease symptoms and to clarify whether they modulate the relationship between oesophageal acid exposure and symptoms. METHODS: The relationship between oesophageal acid exposure, irritable bowel syndrome (Rome I criteria), smoking status and symptoms was investigated in patients with a normal gastroscopy who underwent a 24-h oesophageal pH monitoring. RESULTS: Of 256 patients with gastro-oesophageal reflux disease, 16% were smokers and 50% met the criteria for irritable bowel syndrome (irritable bowel syndrome+). The extent of oesophageal acid exposure was unrelated to smoking or irritable bowel syndrome status. Oesophageal acid exposure, irritable bowel syndrome status and current smoking independently predicted symptoms. Irritable bowel syndrome and smoking modulated the effect of oesophageal acid exposure on symptoms: oesophageal acid exposure was predictive of symptoms only in non-smokers. However, irritable bowel syndrome was a significant predictor of symptoms both in smokers and in non-smokers. Smoking was associated with symptoms only in irritable bowel syndrome+, while oesophageal acid exposure was associated with symptoms irrespective of irritable bowel syndrome status. CONCLUSIONS: In patients with non-erosive gastro-oesophageal reflux disease, smoking and irritable bowel syndrome independently predicted symptoms, without affecting the extent of oesophageal acid exposure. The relationship between oesophageal acid exposure and symptoms was affected significantly, and in opposite directions, by smoking and irritable bowel syndrome.     

Subtyping the irritable bowel syndrome by predominant bowel habit: Rome II versus Rome III

BACKGROUND: The agreement between subtyping irritable bowel syndrome (IBS) patients based on Rome II criteria versus Rome III criteria is unknown. AIM: To compare IBS subtyping based on Rome II versus III criteria. METHODS: The Rome II Modular Questionnaire and the Bristol Stool Form Scale (one-week diary cards) were completed by 249 IBS patients. Based on the Rome II criteria, patients were defined as having diarrhoea- or constipation-predominant IBS, or alternating IBS. Based on the Rome III criteria, patients were divided into IBS with constipation, IBS with diarrhoea, mixed IBS or unsubtyped IBS. Agreement between Rome II and Rome III was assessed with kappa statistics. RESULTS: Based on Rome II there were 92 diarrhoea-predominant IBS, 45 constipation-predominant IBS and 112 alternating IBS, and based on Rome III 97 IBS with diarrhoea, 77 IBS with constipation, 16 mixed IBS and 59 unsubtyped IBS. The agreement between Rome II and Rome III subgroups was 46% (kappa = 0.19). Changes from the constipation to the diarrhoea subgroups and vice versa were uncommon (8% of patients). The majority of changes occurred from/to the alternating IBS, mixed IBS and unsubtyped IBS subgroups. CONCLUSION: There is poor agreement between subtyping of IBS patients based on Rome II versus Rome III criteria.     

Predictive factors of irritable bowel syndrome improvement: 1-year prospective evaluation in 400 patients

BACKGROUND: The natural history of the irritable bowel syndrome is poorly understood. AIM: To assess the clinical course of the irritable bowel syndrome and the factors that might predict it. METHODS: An observational prospective study, involving 400 irritable bowel syndrome patients meeting Rome II criteria. Symptoms were recorded in a diary over four non-consecutive months (1, 4, 7 and 10). Demographic data, associated disorders, psychological status and health-related quality of life were obtained. RESULTS: At 1-year follow-up, half of the patients and half of their physicians considered irritable bowel syndrome to have improved, but improvement was minor. Diary data showed that, according to the type of symptom, improvement was small and quite different: diarrhoea in 19% of patients, abdominal pain frequency in 26%, constipation in 33% and abdominal pain intensity in 60%. Factors related to improvement at one year were: severe symptoms and poor health-related quality of life at first visit, irritable bowel syndrome-constipation, good improvement at 3 months, anxiety/depression, stress, symptoms related to meals and absence of comorbidity. By multivariate logistic regression, predictors were: severe basal symptoms and good improvement at 3 months (OR:CI 95%, 1.32:1.09-1.59 and 4.44:2.81-7.05). CONCLUSIONS: At 1-year follow-up, half the patients and their physicians considered the irritable bowel syndrome to have had some improvement but, symptom diaries demonstrated that improvement was small and heterogeneous. Severe basal symptoms and improvement at 3 months were related to better prognosis.     

Anxiety but not depression determines health care-seeking behaviour in Chinese patients with dyspepsia and irritable bowel syndrome: a population-based study

AIMS: To study the prevalence of dyspepsia and irritable bowel syndrome and the effects of co-existing anxiety and depression on health care utilization by a population survey in Chinese. METHODS: Ethnic Chinese households were invited to participate in a telephone survey using a validated bowel symptom questionnaire and the hospital anxiety and depression scale. Gastrointestinal symptoms were classified as dyspepsia and irritable bowel syndrome according to the Rome I criteria and gastro-oesophageal reflux disease by the presence of weekly heartburn or acid regurgitation. The anxiety and depression scores were compared between patients who sought medical attention and those who did not, using multiple logistic regression analysis. RESULTS: One thousand, six hundred and forty-nine subjects completed the interview (response rate, 62%). The population prevalences of dyspepsia, irritable bowel syndrome and gastro-oesophageal reflux disease were 18.4%, 4.1% and 4.8%, respectively. Dyspepsia and irritable bowel syndrome were associated with anxiety, depression, medical consultation, sick leave and adverse effects on social life. The degree of anxiety was an independent factor associated with health care-seeking behaviour in both dyspeptics (P = 0.003) and irritable bowel syndrome patients (P = 0.036). CONCLUSIONS: Irritable bowel syndrome and dyspepsia are associated with anxiety, depression, significant social morbidity, health care utilization and days off work. Anxiety is an independent factor in determining health care utilization in patients with dyspepsia and irritable bowel syndrome.     

Current patterns of irritable bowel syndrome in Taiwan: the Rome II questionnaire on a Chinese population

BACKGROUND: Irritable bowel syndrome is a common condition seen in Western countries. In Asia, however, it is less known and even less studied. AIM: To determine the prevalence and social impact of irritable bowel syndrome as well as the health-seeking behaviour of irritable bowel syndrome patients in Taiwan METHODS: Using the modified Rome II questionnaire, a survey was carried out in a population receiving physical check-up (n = 2865). RESULTS: The prevalence of irritable bowel syndrome in Taiwan was 22.1% and 17.5% (kappa = 0.73) according to the Rome II and I criteria, respectively. No gender difference was found between subjects with and without irritable bowel syndrome symptoms. Irritable bowel syndrome subjects were likely to undertake an excessive number of physician-visits (P < 0.01). Such subjects were often absent from work/school, with more days of absenteeism than irritable bowel syndrome-free subjects (P < 0.01). They also suffered obvious sleep disturbance (P < 0.01). Nearly half of the irritable bowel syndrome subjects were 'consulters', and they were more likely to have frequent physician-visits, suffer from work/school absenteeism, and endure sleep disturbance and bowel symptoms than irritable bowel syndrome nonconsulters (P < 0.05). CONCLUSIONS: Irritable bowel syndrome is common in a Chinese population of Taiwan. Similar to irritable bowel syndrome in the West, it also involves significant social and medical burdens. However, in the irritable bowel syndrome subjects of Taiwan there is no gender difference, and more irritable bowel syndrome subjects will seek physician consultations, which may be due to Taiwan's easily accessible and affordable heath care facilities.     

Hydrogen glucose breath test to detect small intestinal bacterial overgrowth: a prevalence case-control study in irritable bowel syndrome

BACKGROUND: Studies assessing the prevalence of small intestinal bacterial overgrowth in irritable bowel syndrome gave contrasting results. Differences in criteria to define irritable bowel syndrome patients and methods to assess small intestinal bacterial overgrowth may explain different results. Moreover, no data exist on small intestinal bacterial overgrowth prevalence in a significant population of healthy non-irritable bowel syndrome subjects. AIM: To assess the prevalence of small intestinal bacterial overgrowth by glucose breath test in patients with irritable bowel syndrome symptoms with respect to a consistent control group. METHODS: Consecutive patients with irritable bowel syndrome according to Rome II criteria were enrolled. The control population consisted of 102 sex- and age-matched healthy subjects without irritable bowel syndrome symptoms. All subjects underwent glucose breath test. A peak of H2 values >10 p.p.m above the basal value after 50 g of glucose ingestion was considered suggestive of small intestinal bacterial overgrowth. RESULTS: A total of 65 irritable bowel syndrome patients and 102 healthy controls were enrolled. Positivity to glucose breath test was found in 31% of irritable bowel syndrome patients with respect to 4% in the control group, the difference between groups resulting statistically significant (OR: 2.65; 95% CI: 3.5-33.7, P < 0.00001). CONCLUSIONS: The present case-control study showed an epidemiological association between irritable bowel syndrome and small intestinal bacterial overgrowth. Placebo-controlled small intestinal bacterial overgrowth-eradication studies are necessary to clarify the real impact of small intestinal bacterial overgrowth on irritable bowel syndrome symptoms.     

The prevalence,patterns and impact of irritable bowel syndrome: an international survey of 40,000 subjects

AIM: To determine the prevalence, symptom pattern and impact of the irritable bowel syndrome, across eight European countries, using a standardized methodology. METHODS: A community survey of 41 984 individuals was performed using quota sampling and random digit telephone dialing to identify those with diagnosed irritable bowel syndrome or those meeting diagnostic criteria, followed by in-depth interviews. RESULTS: The overall prevalence was 11.5% (6.2-12%); 9.6% had current symptoms, 4.8% had been formally diagnosed and a further 2.9%, 4.2% and 6.5% met the Rome II, Rome I or Manning criteria, respectively. Bowel habit classification varied by criteria: 63% had an 'alternating' bowel habit by Rome II vs. 21% by self-report. On average, 69% reported symptoms lasting for 1 h, twice daily, for 7 days a month. Irritable bowel syndrome sufferers reported more peptic ulcer (13% vs. 6%), reflux (21% vs. 7%) and appendectomy (17% vs. 11%), but not hysterectomy, cholecystectomy or bladder procedures. Ninety per cent had consulted in primary care and 17% in hospital; 69% had used medication. Irritable bowel syndrome substantially interfered with lifestyle and caused absenteeism. CONCLUSIONS: Irritable bowel syndrome is common with major effects on lifestyle and health care. The majority of cases are undiagnosed and the prevalence varies strikingly between countries. Diagnostic criteria are associated with varying prevalences and bowel habit sub-types. This limits their utility in clinical practice and the transferability of research findings using them.     

Gender difference on the symptoms, health-seeking behaviour, social impact and sleep quality in irritable bowel syndrome: a Rome II-based survey in an apparent healthy adult Chinese population in Taiwan

BACKGROUND: Little is known about the gender effect on irritable bowel syndrome in Asia. AIM: To assess the gender difference in Chinese subjects with irritable bowel syndrome meeting Rome II criteria. METHODS: Irritable bowel syndrome was identified from an apparently healthy adult population receiving a routine health maintenance program (n = 2018). RESULTS: Female gender is not a factor associated with irritable bowel syndrome or irritable bowel syndrome-related health care-seeking behaviour. Female irritable bowel syndrome subjects, irrespective of consulting behaviour for irritable bowel syndrome, are likely to have < 3 bowel movements/week, hard/lumpy stools and abdominal fullness/bloating (P < 0.05). Female irritable bowel syndrome subjects are prone to be absent from school/work with more days of absenteeism, irrespective of consultation status (P < 0.05). Only female irritable bowel syndrome consulters have more absenteeism for their irritable bowel syndrome-related symptoms, reporting more sleep disturbances than their male counterparts (P < 0.001). CONCLUSIONS: In an apparent healthy adult population in Taiwan, gender difference is present in Rome II defined Chinese subjects with irritable bowel syndrome as regards bowel symptoms, social impact and sleep quality. Female predominance was not found in irritable bowel syndrome subjects and irritable bowel syndrome-related health care-seeking behaviour in the current population. Both irritable bowel syndrome non-consulters and consulters have similar gender difference profiles in presenting symptoms, suggesting that bowel symptoms per se may not be the only factor leading to health care-seeking behaviour. The gender differences in sleep problems were observed solely in irritable bowel syndrome consulter.     

The effect of fluoxetine in patients with pain and constipation-predominant irritable bowel syndrome: a double-blind randomized-controlled study

BACKGROUND: Irritable bowel syndrome has been treated with selective serotonin reuptake inhibitors but there is not enough evidence from controlled trials to prove their effectiveness. AIM: To compare the effects of fluoxetine and placebo in the treatment of pain and constipation-predominant irritable bowel syndrome in a double-blind randomized-controlled trial. METHODS: Forty-four cases meeting Rome II criteria for irritable bowel syndrome with predominance of pain and constipation were included in this study. Organic causes were ruled out by detailed history, physical examination, laboratory tests and colonoscopy. Participants were then randomly assigned to receive either fluoxetine or placebo for 12 weeks. Symptoms addressed by the Rome II criteria were recorded during treatment and 4 weeks after termination of treatment. RESULTS: Fluoxetine was significantly more effective than placebo in decreasing abdominal discomfort, relieving feeling and sense of bloating, increasing frequency of bowel movements and decreasing consistency of stool. Mean number of symptoms per patient decreased from 4.6 to 0.7 in the fluoxetine group vs. 4.5 to 2.9 in controls (P < 0.001). CONCLUSIONS: Fluoxetine is an effective and well-tolerated short-term treatment for pain and constipation-predominant irritable bowel syndrome.     

Effect of tegaserod on work and daily activity in irritable bowel syndrome with constipation

BACKGROUND: Tegaserod is a promotility agent with proven efficacy and safety in patients with irritable bowel syndrome with constipation. AIM: To assess tegaserod's effect on work productivity and daily activity. METHODS: Women, 18-65 years old and meeting Rome II criteria for irritable bowel syndrome with constipation, were randomized to a double-blind, placebo-controlled, multicentre study of tegaserod 6 mg b.d. or placebo. Productivity loss and daily activity impairment because of irritable bowel syndrome were measured with the Work Productivity and Activity Impairment questionnaire for irritable bowel syndrome, modified to exclude diarrhoea as a symptom. Assessments were made at baseline, weeks 2 and 4. RESULTS: A total of 2660 women were randomized and, of these, 1675 [tegaserod (n = 1363), placebo (n = 312)] were employed and completed Work Productivity and Activity Impairment for irritable bowel syndrome questionnaires. Compared with placebo, tegaserod significantly reduced work and daily activity impairment at weeks 2 and 4. Tegaserod reduced absenteeism by 2.6% (P = 0.004), presenteeism by 5.4% (P < 0.0001), overall work productivity loss by 6.3% (P < 0.0001), and activity impairment by 5.8% (P < 0.0001) at week 4 (vs. baseline). Assuming a 40-h workweek, tegaserod reduced work productivity loss by 2.5 h/week. CONCLUSIONS: Tegaserod significantly reduced work productivity loss and daily activity impairment at 2 weeks, and this benefit was maintained at 4 weeks.     

Naloxone treatment for irritable bowel syndrome--a randomized controlled trial with an oral formulation

BACKGROUND: Opioids change gut motility and secretion, causing delayed intestinal transit and constipation. Endorphins play a role in the constipation troubling some patients with irritable bowel syndrome; hence naloxone, an opioid antagonist, may have a therapeutic role. AIM: To assess the efficacy and safety of an oral formulation of naloxone in irritable bowel syndrome patients with constipation. METHODS: A randomized, double-blind, placebo-controlled trial was performed. Patients fulfilling the Rome II criteria for irritable bowel syndrome (constipation-predominant and alternating types) were randomized to receive 8 weeks of treatment with naloxone capsules, 10 mg twice daily, or identical placebo. RESULTS: Twenty-eight patients entered the study, which was completed by 25. 'Adequate symptomatic relief' was recorded in six of 14 on naloxone and three of 11 on placebo. Whilst the differences were not significant, improvements in severity gradings and mean symptom scores for pain, bloating, straining and urgency to defecate were greater with naloxone than placebo for all parameters. In addition, quality of life assessments improved to a greater extent in patients taking naloxone. CONCLUSIONS: Preliminary results suggest that naloxone is well tolerated and beneficial in patients with irritable bowel syndrome and constipation. A larger clinical trial is needed to provide sufficient statistical power to assess efficacy.     

Irritable bowel syndrome in the United States: prevalence, symptom patterns and impact

BACKGROUND: The impact of irritable bowel syndrome, a gastrointestinal motility disorder, is underestimated and poorly quantified, as clinicians may see only a minority of sufferers. AIM: To determine the prevalence, symptom patterns and impact of irritable bowel syndrome in the US. METHODS: This two-phase community survey used quota sampling and random-digit telephone dialing (screening interview) to identify individuals with medically diagnosed irritable bowel syndrome or individuals not formally diagnosed, but fulfilling irritable bowel syndrome diagnostic criteria (Manning, Rome I or II). Information on irritable bowel syndrome symptoms, general health status, lifestyle and impact of symptoms on individuals' lives was collected using in-depth follow-up interviews. Data were also collected for healthy controls identified in the screening interviews. RESULTS: The total prevalence of irritable bowel syndrome in 5009 screening interviews was 14.1% (medically diagnosed: 3.3%; undiagnosed, but meeting irritable bowel syndrome criteria: 10.8%). Abdominal pain/discomfort was the most common symptom prompting consultation. Most sufferers (74% medically diagnosed; 63% undiagnosed) reported alternating constipation and diarrhoea. Previously diagnosed gastrointestinal disorders occurred more often in sufferers than non-sufferers. Irritable bowel syndrome sufferers had more days off work (6.4 vs. 3.0) and days in bed, and reduced activities to a greater extent than non-sufferers. CONCLUSIONS: Most (76.6%) irritable bowel syndrome sufferers in the US are undiagnosed. Irritable bowel syndrome has a substantial impact on sufferers' well-being and health, with considerable socioeconomic consequences.     

Burden of illness in irritable bowel syndrome comparing Rome I and Rome II criteria

OBJECTIVES: To evaluate the burden of illness in irritable bowel syndrome (IBS), in terms of resource utilisation (direct and indirect) and health-related quality of life (HR-QOL), in individuals with IBS who meet Rome I and Rome II criteria. METHODS: A cross-sectional study, carried out by personal interview, on a representative sample (n = 2000) of the Spanish population. Individuals with suspected IBS were identified via a screening question and subsequently given an epidemiological questionnaire to complete. The questionnaire collected information on IBS symptoms, resource utilisation, and HR-QOL [Medical Outcomes Study 36-item Short Form (SF-36)]. RESULTS: Sixty-five individuals met Rome II criteria for IBS, while 146 individuals met exclusively Rome I criteria. Of Rome II individuals, 67.7% had consulted some type of healthcare professional in the previous 12 months, compared with only 41.8% of those individuals meeting exclusively Rome I criteria (p vs 17.1%); 'drug consumption' (70.8 vs 45.2%); and 'reduced performance in main activity' (60 vs 27.4%). Compared with the general population, the study sample reported significantly worse HR-QOL scores in four dimensions of the SF-36 ('bodily pain', 'vitality', 'social functioning' and 'role-emotional'. Additionally, individuals meeting Rome II criteria reported worse HR-QOL scores than those individuals meeting exclusively Rome I criteria, especially in the 'bodily pain' and 'general health' dimensions. CONCLUSIONS: The burden of illness in IBS is important and correlated to the diagnostic criteria employed. Individuals who met Rome II criteria reported a higher level of resource utilisation and worse HR-QOL than individuals meeting exclusively Rome I criteria.     

Diagnostic accuracy of faecal calprotectin estimation in prediction of abnormal small bowel radiology

BACKGOUND: Patients being investigated for symptoms of abdominal pain, diarrhoea and or weight loss often undergo small bowel radiology as part of their diagnostic workup mainly to exclude inflammatory bowel disease. AIM: To assess and compare the utility of a single faecal calprotectin estimation to barium follow through as well as conventional inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein in exclusion of intestinal inflammation. METHODS: Seventy-three consecutive cases undergoing barium follow through for investigation of symptoms of diarrhoea and or abdominal pain with or without weight loss were studied. The control group comprised 25 cases with known active Crohn's disease (positive controls), 26 normal healthy volunteers (negative controls) and 25 cases of irritable bowel syndrome diagnosed by Rome II criteria. Symptoms, erythrocyte sedimentation rate and C-reactive protein were recorded at recruitment and a single stool sample assayed for calprotectin within 7 days prior to or after barium follow through. Results: The median calprotectin value in the active Crohn's group, irritable bowel syndrome group and normal volunteers was 227 microg/g of stool, 19 and 10 microg/g respectively (P < 0.0001). A faecal calprotectin above a cut-off value of 60 microg/g was able to predict all nine cases with an abnormal barium follow through as well as all six cases with a normal barium follow through but with organic intestinal disease. The negative predictive value of a single calprotectin result below 60 microg/g of stool was 100% compared with 91% each for erythrocyte sedimentation rate > 10 mm and C-reactive protein > 6 mg/L and 84% for a combination of erythrocyte sedimentation rate and C-reactive protein in predicting absence of organic intestinal disease. CONCLUSION: A single stool calprotectin value < 60 microg/g of stool obviates the need for further barium radiology of the small bowel, is more accurate than measurement of erythrocyte sedimentation rate or C-reactive protein and effectively excludes Crohn's disease or non-functional gastrointestinal disease.     

Clinical trial: the effect of amitriptyline in patients with diarrhoea-predominant irritable bowel syndrome

Background Irritable bowel syndrome is the most common disorder diagnosed by gastroenterologists. Although several randomized‐controlled trials have assessed the therapeutic role of antidepressant drugs, there is insufficient evidence to support their use. Aim To compare the effects of low‐dose amitriptyline in the treatment of diarrhoea‐predominant irritable bowel syndrome in a double‐blind randomized‐controlled trial. Methods Fifty‐four patients who fulfilled Rome II criteria for diarrhoea‐predominant irritable bowel syndrome were included in this study. Organic causes were ruled out by standard laboratory and radiological tests, and rectosigmoidoscopy. Patients were randomly assigned to receive either 10 mg amitriptyline daily or placebo. Subjects were followed up for 2 months and symptoms were assessed using a questionnaire. Intention‐to‐treat and per‐protocol analysis was performed. Results Fifty patients completed the study. At 2 months, the amitriptyline group showed greater (P < 0.05) reduction in the incidence of loose stool and feeling of incomplete defecation. Patients receiving amitriptyline showed greater complete response, defined as loss of all symptoms, compared with those receiving placebo (68% vs. 28%, P = 0.01). Adverse effects were similar between the two groups. Conclusion Amitriptyline may be effective in the treatment of diarrhoea‐predominant irritable bowel syndrome and at low dose is well tolerated.     

A population-based epidemiologic study of irritable bowel syndrome in South China: stratified randomized study by cluster sampling

BACKGROUND: The detailed population-based data on irritable bowel syndrome in South China are lacking. AIMS: To assess the prevalence of irritable bowel syndrome in South China and its impact on health-related quality of life. SUBJECTS AND METHODS: A face-to-face interview was carried out in South China to assess the prevalence of irritable bowel syndrome. Random clustered sampling of permanent inhabitants aged 18-80 years was carried out under stratification of urban and suburban areas. The impact of irritable bowel syndrome on health-related quality of life was evaluated using the Chinese version of SF-36. RESULTS: A total of 4178 subjects (1907 male and 2271 female) were interviewed. The adjusted prevalence of irritable bowel syndrome in South China is 11.50% according to the Manning criteria and 5.67% according to the Rome II criteria. Factors including history of analgesic use such as non-steroidal anti-inflammatory drug (odds ratio 3.83), history of food allergies (odds ratio 2.68), psychological distress (odds ratio 2.18), life events (odds ratio 1.89), history of dysentery (odds ratio 1.63) and negative coping style (odds ratio 1.28) were significantly associated with the presence of irritable bowel syndrome (P < 0.05). Irritable bowel syndrome was significantly associated with a decrement in health-related quality of life score. CONCLUSION: Irritable bowel syndrome is a common disorder in South China and has a negative impact on health-related quality of life.     

Stability of the irritable bowel syndrome and subgroups as measured by three diagnostic criteria – a 10‐year follow‐up study

Aliment Pharmacol Ther 2010; 32: 670–680

Summary

Background The irritable bowel syndrome (IBS) is a common disorder, but information on its natural history is limited. Aim To study the performance of four IBS criteria in detecting incidence and stability of categories over a 10‐year period. Method This study was a population‐based postal study. Questionnaire was mailed to the same age‐ and gender‐stratified random sample of the Icelandic population aged 18–75 years in 1996 and again in 2006. IBS was estimated by the Manning criteria, Rome II, Rome III, subgroups and self‐report. Results Prevalence of IBS varied according to criteria: Manning showed the highest (32%) and Rome II the lowest (5%). Younger subjects and females were more likely to have IBS. Prevalence was stable over 10 years for all criteria except Rome III. There was a turnover in all IBS subgroups and a strong correlation among IBS, functional dyspepsia and heartburn. Conclusions The prevalence of the IBS remained stable over a 10‐year period with a turnover in symptoms. The study suggests that IBS is a cluster of symptoms that float in time between different IBS categories, functional dyspepsia and heartburn. The irritable bowel syndrome in Iceland is very common and indicates a chronic condition, which poses a heavy burden on the health care system.