A comparison of the Rome and Manning criteria for case identification in epidemiological investigations of irritable bowel syndrome

Irritable bowel syndrome: a review on the role of intestinal protozoa and the importance of their detection and diagnosis

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder in which abdominal pain is associated with a defect or a change in bowel habits. Gut inflammation is one of the proposed mechanisms of pathogenesis. Recent studies have described a possible role for protozoan parasites, such as Blastocystis hominis and Dientamoeba fragilis, in the etiology of IBS. Dientamoeba fragilis is known to cause IBS-like symptoms and has a propensity to cause chronic infections but its diagnosis relies on microscopy of stained smears, which many laboratories do not perform, thereby leading to the misdiagnosis of dientamoebiasis as IBS. The role of B. hominis as an etiological agent of IBS is inconclusive, due to contradictory reports and the controversial nature of B. hominis as a human pathogen. Although Entamoeba histolytica infections occur predominately in developing regions of the world, clinical diagnosis of amebiasis is often difficult because symptoms of patients with IBS may closely mimic those patients with non-dysenteric amoebic colitis. Clinical manifestations of Giardia intestinalis infection also vary from asymptomatic carriage to acute and chronic diarrhoea with abdominal pain. These IBS-like symptoms can be continuous, intermittent, sporadic or recurrent, sometimes lasting years without correct diagnosis. It is essential that all patients with IBS undergo routine parasitological investigations in order to rule out the presence of protozoan parasites as the causative agents of the clinical signs.

Gastrointestinal complaints in patients with eating disorders

BACKGROUND

Patients with eating disorders (EDs) typically have numerous somatic and gastrointestinal complaints. Early referral to treatment may result in improved outcomes. We sought to determine whether patients with EDs were presenting to gastroenterologists or primary care physicians with gastrointestinal complaints early in the disease course, when referral for specialized, comprehensive treatment would be most beneficial.

STUDY

Over a 1-year period, we administered a structured interview to a cohort of patients presenting for inpatient ED treatment. We also conducted the same interview on an age-matched cohort of medical students to determine baseline incidences of various gastrointestinal healthcare behaviors.

RESULTS

Patients with bulimia nervosa were significantly more likely to seek healthcare for a gastrointestinal complaint before seeking treatment for an ED than were controls. Patients with EDs were significantly more likely to be prescribed medication for the gastrointestinal tract than were controls.

CONCLUSION

Gastroenterologists and primary care physicians should employ available instruments to screen young women of low to normal weight with gastrointestinal complaints for possible EDs. Referral to specialized treatment programs should be made promptly when an ED is identified.

Postinfectious irritable bowel syndrome--a meta-analysis

OBJECTIVES

Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 12% of the population worldwide. Several studies identify IBS as a sequela of infectious gastroenteritis (IGE) with reported prevalence ranging from 4% to 31% and relative risk from 2.5 to 11.9. This meta-analysis was conducted to explore the differences between reported rates and provide a pooled estimate of risk for postinfectious irritable bowel syndrome (PI-IBS).

DATA SOURCES

Electronic databases (MEDLINE, OLDMEDLINE, EMBASE, Cochrane database of clinical trials) and pertinent reference lists (including other review articles).

REVIEW METHODS

Data were abstracted from included studies by two independent investigators; study quality, heterogeneity, and publication bias were assessed; sensitivity analysis was performed; and a summative effect estimate was calculated for risk of PI-IBS.

RESULTS

Eight studies were included for analysis and all reported elevated risk of IBS following IGE. Median prevalence of IBS in the IGE groups was 9.8% (IQR 4.0-13.3) and 1.2% in control groups (IQR 0.4-1.8) (sign-rank test, p= 0.01). The pooled odds ratio was 7.3 (95% CI, 4.7-11.1) without significant heterogeneity (chi2 heterogeneity statistic, p= 0.41). Subgroup analysis revealed an association between PI-IBS risk and IGE definition used.

CONCLUSIONS

This study provides supporting evidence for PI-IBS as a sequela of IGE and a pooled risk estimate revealing a sevenfold increase in the odds of developing IBS following IGE. The results suggest that the long-term benefit of reduced PI-IBS may be gained from primary prevention of IGE.

Physicians' attitudes and practices in the evaluation and treatment of irritable bowel syndrome

OBJECTIVE

Irritable bowel syndrome (IBS) is a common disorder characterized by abdominal discomfort and disordered bowel habits. Despite the high prevalence of IBS, little is known about how physicians perceive this condition. The aims of our study were to measure physicians' understanding of IBS, to assess their attitudes towards patients with IBS, and to determine whether there are differences in the way Internal Medicine physicians (IM), Family Practice physicians (FP), and Gastroenterology physicians (GI) evaluate and treat IBS patients.

MATERIAL AND METHODS

A survey was sent to 3000 physicians nationwide, 1000 each to IM, FP, and GI. The survey contained 35 questions assessing demographics, the etiology and pathophysiology of IBS, the use of diagnostic tests, and practice patterns and attitudes.

RESULTS

Of the deliverable questionnaires, 501 were returned completed; 472 of the respondents interviewed only adult patients, representing the cohort for this analysis. The mean age of all respondents was 47; most were men (80%). IM and FP made a new diagnosis of IBS 1.3-1.6 times each week, while GI made a new diagnosis 5.4 times each week (p<0.0001). Compared with the perceptions of FP and IM, GI felt that IBS patients were less sick than other patients (p<0.001), although they required more time per visit. More GI compared with FP and IM stated that prior infection and a history of abuse were the causes of IBS (p<0.01), while FP were more likely to believe that diet was a cause of IBS (p<0.01). GI felt a new diagnosis of IBS could be made without further testing 42% of the time. FP and IM felt that one-third of IBS patients needed referral to a GI.

CONCLUSIONS

The attitudes and practice patterns of physicians towards patients with IBS differ depending on practice specialty. This may be due to differences in training, the ability to perform specialized tests, and/or differences in referral patterns. Further training may improve the ability of physicians in all specialties confidently to diagnose and treat patients with IBS.

Prevalence, comorbidity and impact of irritable bowel syndrome in Norway

OBJECTIVE

To study the prevalence of irritable bowel syndrome (IBS) and its comorbidity in a Norwegian adult population.

MATERIAL AND METHODS

In 2001, 11,078 inhabitants (aged 30-75 years) in Oppland County were invited to take part in a public health survey. A total of 4622 subjects (42%) completed the questionnaires on symptoms of IBS (Rome II criteria), comorbidity, health-care visits and medications. The impact of comorbidity on global health, working disability and use of health-care resources in subjects with IBS was explored by stepwise logistic regression.

RESULTS

The population prevalence of IBS was 388/4622 (8.4% (95% CI: 7.6-9.4%)) with a female predominance and an age-dependent decrease. The proportion who had consulted for IBS ranged from 51% among 30-year-olds to 79% in 75-year-olds (p=0.05). IBS was associated with musculoskeletal complaints (OR = 2.4-3.4 for six different items), fibromyalgia (OR = 3.6 [2.7-4.8]), mood disorder (OR = 3.3 (2.6-4.3)), reduced global health (OR = 2.6 (2.1-3.2)), working disability (OR = 1.6 (1.2-2.1)), more frequent health-care visits and use of medications (OR 1.7-2.3). When controlling for comorbidity, reduced global health (OR = 1.5 (1.1-2.0)) and use of alternative health care (OR = 1.7 (1.3-2.4)) remained associated with IBS. Severity of abdominal pain/discomfort was a predictor of having to seek a physician for IBS (OR = 1.3 (1.2-1.5)).

CONCLUSIONS

Symptoms of IBS were reported by 8% of Norwegian adults and had resulted in consultations with physicians for the majority in the long run. Subjects with IBS in the community were characterized by frequent somatic and psychiatric comorbidity. Their observed reduced health, working disability and increased use of health resources were largely explained by comorbid symptoms and disorders.

Functional findings in irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Several studies have demonstrated altered GI motor function in IBS patients and the pattern differs between IBS subgroups based on the predominant bowel pattern. Few studies have so far addressed GI secretion in IBS, but there are some evidence supporting altered secretion in the small intestine of IBS patients. Visceral hypersensitivity is currently considered to be perhaps the most important pathophysiological factor in IBS. Importantly, several external and internal factors can modulate visceral sensitivity, as well as GI motility, and enhanced responsiveness within the GI tract to for instance stress and nutrients has been demonstrated in IBS patients. Today IBS is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral alterations probably dominating in some patients and disturbed central processing of signals from the periphery in others.

A survey of irritable bowel syndrome in Vietnam using the Rome criteria

Prevalence estimates for irritable bowel syndrome from surveys in Western countries are 4.4% to 22%, generally higher in women than men, and only a minority seek health care. There are few studies of bowel patterns in Asian countries. We conducted a survey of a nonpatient population in Ho Chi Minh City, Vietnam, to determine bowel patterns and the prevalence of bowel dysfunction. A forced-choice, self-report questionnaire was distributed to 738 predominantly health care workers, as well as patient relatives, at Cho Ray Hospital in Ho Chi Minh City and returned by 411 (response rate of 55.7%). Results were analyzed for men and women using Student's t-test for continuous variables and chi-square test for categorical variables. Subjects were 53.6% female, with a mean age of 27.7+/-6.9 years. Overall perception of health was excellent/very good in 13.6%, good in 54.2%, and fair/poor in 32.1% (males, 17.1%, 51.3%, and 31.5%, vs. females, 10.6%, 56.7%, and 32.7%; P=NS). The mean number of stools reported per week was 6.5 (males, 6.6, vs. females, 6.4; P=NS) and ranged between 3 and 21 stools per week in 95.5%. The frequency of irritable bowel syndrome symptoms (using Rome I criteria) was 7.2% (95% CI=4.8-10.1), with males at 4.8% (95% CI=2.2-8.9) vs. females at 9.2% (95% CI=5.7-13.9) (P=0.08). Of the subjects with irritable bowel syndrome symptoms, 6 of 29 (20.7%) had seen a physician for bowel symptoms. There were no gender differences in reported infrequent stool (12.0%), frequent stool (11.3%), hard stool (17.5%), loose stool (6.5%), straining (14.5%), incomplete emptying (16.2%), bloating (15.0%), urgency (10.0%), or mucus (2.7%). In conclusion, this survey of a nonpatient population in Vietnam showed that irritable bowel syndrome symptoms as defined by Rome criteria were common and that there were no significant differences between sexes in either stool frequency or prevalence of irritable bowel syndrome, unlike previous studies from the United States. The prevalence of irritable bowel syndrome in Vietnam in this study was in the lower range of reported data from Western countries, possibly in part related to the use of the Rome criteria. Only a minority of subjects with irritable bowel syndrome symptoms reported seeking health care for these symptoms.

Prevalence, sociodemography, and quality of life of older versus younger patients with irritable bowel syndrome: a population-based study

We studied the prevalence as well as the sociodemographic characteristics and QOL of older adults (> 50 years) with irritable bowel syndrome (IBS) among the population at large and compared it to their younger counterparts'. We hypothesized that IBS is less prevalent among older persons and they suffer poorer QOL compared to younger IBS patients. A total of 1000 adults from nine sites, including a medical center, churches, and a blood bank in our metropolitan area (670 African Americans, 320 Caucasians, and 10 others), completed self-administered questionnaires providing sociodemographic information and details regarding bowel habits and associated symptoms for diagnosing the IBS based on Rome II criteria. QOL was assessed by the SF-12 questionnaire. The study database was divided into two groups, younger (< 50 years) and older (> or = 50 years). The two age groups were similar with respect to gender and household income. Ninety-five of the 1000 participants had IBS, giving a total sample prevalence of 9.5% (< 50 years, 9.9%, vs > or = 50 years, 7.6%). The prevalence of IBS was similar in the two groups irrespective of race, sex, marital status, size of household, location of residence (rural versus urban), level of educational status, and household income. Compared to the older group, there was a trend toward a higher prevalence of IBS among divorced subjects (12.7% vs 0%; P = 0.1) and those below poverty level of income (15.3% vs 7.5%; P = 0.09) in the younger subjects. In contrast, older IBS patients were more likely to attend church regularly (32.5% vs 58.8%; P < 0.05). There were no differences in history of traveler's diarrhea, food intolerance, and drug allergies between the two groups. Health care utilization was similar between the two IBS groups in terms of number of physician visits, use of prescription and alternative medications, and being disabled due to IBS. There was no difference in the overall QOL score means (27.8 vs 29.5; P = NS) or in its general health and physical functioning components. However, older IBS patients had better social functioning (9.1 vs 9.8; P < 0.05). Although in our study IBS occurred less frequently among older adults than among younger patients, the difference is not statistically significant. While IBS affects QOL at all ages, social functioning was actually better on average among older compared to younger IBS patients.

A randomized double-blind placebo-controlled trial of rifaximin in patients with abdominal bloating and flatulence

AIMS

To study the efficacy of rifaximin, a nonabsorbable antibiotic, in relieving chronic functional symptoms of bloating and flatulence.

METHODS

Randomized double-blind placebo-controlled trial consisting of three 10-day phases: baseline (phase 1), treatment with rifaximin 400 mg b.i.d. or placebo (phase 2), and post-treatment period (phase 3). Primary efficacy variable was subjective global symptom relief at the end of each phase. A symptom score was calculated from a symptom diary. Lactulose H2-breath test (LHBT) was performed at baseline and end of study.

RESULTS

One hundred and twenty-four patients were enrolled (63 rifaximin and 61 placebo). Baseline characteristics were comparable and none had an abnormal baseline LHBT. Rome II criteria were met in 58.7% and 54.1%, respectively. At the end of phase 2, there was a significant difference in global symptom relief with rifaximin versus placebo (41.3% vs 22.9%, p = 0.03). This improvement was maintained at the end of phase 3 (28.6% vs 11.5%, p = 0.02). Mean cumulative and bloating-specific scores dropped significantly in the rifaximin group (p < 0.05). Among patients with IBS, a favorable response to rifaximin was noted (40.5% vs 18.2%; p = 0.04) persisting by the end of phase 3 (27% vs 9.1%; p = 0.05). H2-breath excretion dropped significantly among rifaximin responders and correlated with improvement in bloating and overall symptom scores (p = 0.01). No adverse events were reported.

CONCLUSIONS

Rifaximin is a safe and effective treatment for abdominal bloating and flatulence, including in IBS patients. Symptom improvement correlates with reduction in H2-breath excretion. Future trials are needed to examine the efficacy of long-term or cyclic rifaximin in functional colonic disorders.

Prevalence and demographics of irritable bowel syndrome: results from a large web-based survey

BACKGROUND

Irritable bowel syndrome is a common gastrointestinal disorder, and its prevalence and demographics have been evaluated by different methodologies with varying results.

AIM

To evaluate irritable bowel syndrome demographic and prevalence characteristics utilizing a web-enabled panel.

METHODS

From an existing 150 000-member panel, 31 829 individuals were randomly selected and sent screening questionnaires to evaluate irritable bowel syndrome symptoms. Individuals who agreed to participate and completed the screening questionnaire received a second questionnaire related to a diagnosis of irritable bowel syndrome, a more detailed symptom description, and additional burden of illness data.

RESULTS

Irritable bowel syndrome prevalence was 7%. Prevalence was higher in women vs. men, unmarried individuals vs. married individuals and unemployed individuals vs. employed individuals. Of those completing the second questionnaire, 51% had seen their physicians for irritable bowel syndrome symptoms in the past year and most had an episode within the past 3 months. During the past year, approximately half of the participants had used a prescription medication, and over 90% had used an over-the-counter medication for irritable bowel syndrome. Participants with irritable bowel syndrome demonstrated quality-of-life reductions relative to norms of the United States population.

CONCLUSIONS

Web-enabled data collection represents a novel tool for rapidly surveying a large population of individuals with irritable bowel syndrome symptoms.

The genetics of irritable bowel syndrome

Because of the heterogeneity in symptoms and diagnostic findings, patients with irritable bowel syndrome (IBS) remain a challenge to treat and to study. This difficulty stems from lack of understanding of the pathophysiology of this disorder. Environmental factors likely play an important role in the pathogenesis and clinical manifestations of IBS. Several recent studies suggest a genetic basis for IBS, either in etiology or predicting response to therapy. Because of interest in studying the genetic contributors to this and other functional gastrointestinal disorders, we review the literature on genetic risk factors that might explain the familial clustering of IBS. Familial aggregation studies and twin studies suggest a modest contribution of genetics to the development of IBS. Pharmacogenomic and association studies provide stronger, although far from conclusive, evidence for genetic variants that affect expression of IBS. Together, these studies suggest that a multidisciplinary approach with clinical and psychological tools, epidemiologic methods, and genetic techniques might help elucidate the molecular components leading to the common symptoms of IBS and result in better treatments for those with IBS.

Increased prevalence of functional gastrointestinal disorders in panic disorder: clinical and theoretical implications

BACKGROUND

Functional gastrointestinal disorders (FGID) are a group of disorders characterized by recurrent gastrointestinal distress for which no structural or biochemical cause can be discerned. Irritable bowel syndrome (IBS) is an FGID estimated to affect 10% to 25% of the United States population. IBS occurs in over 40% of individuals with panic disorder, and in patients with IBS, 25% to 30% have panic disorder, which has led to speculation about possible shared pathophysiology between the two. Less is known about the prevalence of other FGID in individuals with panic disorder.

OBJECTIVE

The purpose of this study was to examine the prevalence of IBS and all the other FGID in patients with current Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) panic disorder.

INTRODUCTION

We assessed FGIDs in 73 treatment-seeking DSM-IV panic disorder patients via the Diagnostic Interview Questions for Functional Gastrointestinal Disorders and made descriptive comparisons with a large convenience sample from an already-completed United States Household Survey (USHS), which employed the same diagnostic criteria.

RESULTS

The prevalence of IBS and other FGIDs in both men and women with panic disorder were substantially higher than in the USHS respondents. Women with panic disorder had significantly more functional chest pain than men, but there was no gender difference in IBS. With the exception of functional anorectal and biliary disorders, the FGID prevalences were comparatively higher in panic disorder versus the USHS respondents.

DISCUSSION

This survey supports earlier reports of a high prevalence of IBS in individuals with panic disorder and also suggests that the prevalence of several other FGIDs were comparatively high as well. Methodological limitations precluded direct statistical analysis. It may be that commonly overlapping psychiatric and often-painful FGIDs, and extra-intestinal disorders increase the risk for comorbidity in already-affected individuals via shared pathophysiology. One potential model for which there is some evidence for a role in stress, panic disorder, FGIDs and several extra-intestinal functional conditions is dysregulation of corticotropin-releasing factor function.

CONCLUSION

The prevalence of FGIDs in DSM-IV panic disorder was comparatively higher than in USHS respondent community sample, which used similar FGID diagnostic criteria. The cause for the apparent close association of panic disorder with FGID may represent shared pathophysiology. Increased understanding of the mechanism of the overlap may allow for improved treatment of the significant proportion of the population suffering from comorbid psychiatric and functional medical conditions.

Epidemiology of irritable bowel syndrome among African Americans as compared with whites: a population-based study

BACKGROUND & AIMS

We studied the prevalence as well as the sociodemographic characteristics and quality of life of African American patients with irritable bowel syndrome (IBS) among the population at large and compared them with those of whites.

METHODS

A total of 990 adults from 9 different sites in the Jackson, Mississippi metropolitan area (670 African Americans and 320 whites) completed self-administered questionnaires providing sociodemographic information and details regarding bowel habits and associated symptoms for diagnosing IBS on the basis of Rome II criteria. Quality of life was assessed by the SF-12 questionnaire.

RESULTS

Ninety-five of the 990 participants had IBS, giving a total sample prevalence of 9.6% (African Americans, 7.9%; whites, 13.1%). Adjusting for other risk factors in a reduced logistic regression model, we found race (P = .0004) and education (P = .0049) to be important correlates of IBS prevalence. The household income showed a trend toward statistical significance (P = .0845). With the adjusted odds ratio as an estimate of relative risk, whites were 2.5 (95% confidence interval, 1.5-4.0) more likely than African Americans to have IBS. In terms of an index for quality of life (possible score, 1-44), the adjusted mean score was lower for adults with IBS compared with non-IBS adults (IBS mean, 29.8; no IBS, 34.2; P < .0001), but the racial difference was not significant.

CONCLUSIONS

IBS occurs less frequently among African Americans. Although IBS affects quality of life among both ethnicities, the degree of impairment is similar.

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.

Irritable bowel syndrome: epidemiology, natural history, health care seeking and emerging risk factors

IBS is a common condition, affecting approximately 3% to 15% of the general population based on various diagnostic criteria. There seem to be differences in disease epidemiology between the eastern and the western world. As data from larger Asian epidemiological studies begin to surface,however, such differences appear to be less marked. The proportion of IBS patients who consult a physician for their symptoms is around 50%. Psychological factors and the presence and duration of abdominal pain are all significant predictors for health care seeking. The natural history of IBS is characterized by frequent fluctuation of symptoms and by an overlap with other functional GI disorders, some of which share a number of risk factors for IBS. Unnecessary abdominal surgery is performed in a high proportion of IBS sufferers. Along with the established role for psychosocial conditions in IBS, other risk factors are emerging. Evidence for postinfectious IBS is mounting, but the clinical usefulness of characterizing such patients remains unclear. Food sensitivities are frequently present in IBS, but more well-conducted trials of avoidance diets and desensitization are needed. Finally,genetic markers in IBS are an increasing focus of attention, but the amount of phenotypic variance explained by genetic variability remains to be established.

The placebo effect in irritable bowel syndrome trials: a meta-analysis

BACKGROUND

Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response.

OBJECTIVES

To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response.

METHODS

We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied.

FINDINGS

Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026).

CONCLUSIONS

Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

Diagnosis of irritable bowel syndrome

Because there are no reliable biological or laboratory markers associated with the condition, the diagnosis of irritable bowel syndrome(IBS) is based on patient descriptions of common symptoms such as abdominal pain accompanied by changes in stool form or frequency and associated symptoms such as bloating and distension. With the development and refinement of symptom-based criteria for the diagnosis of IBS, the traditional need for a negative diagnostic evaluation has been questioned. This article evaluates the diagnostic characteristics of various symptom-based criteria in routine clinical practice and reviews the data regarding the yield of the multiple commonly used diagnostic tests in patients with suspected IBS.

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.

Irritable bowel syndrome: a syndrome in evolution

As a group, functional gastrointestinal disorders are the most common gastrointestinal disorder seen by both generalists and specialists. These disorders can be frustrating to both patients and physicians as they are usually chronic in nature and difficult to treat. These disorders are associated with frequent healthcare visits, the scheduling of multiple, expensive diagnostic tests, and the use of both over-the-counter and prescription medications. All of these factors lead to a significant economic burden to society. In addition, functional gastrointestinal disorders are associated with a reduction in quality of life for the patient. Irritable bowel syndrome (IBS) is the most common of the functional gastrointestinal disorders. This syndrome has been the focus of a large number of research studies over the past two decades. These studies have resulted in a number of significant changes in our definition of IBS. In addition, these research studies have produced considerable changes in our understanding of the etiology and pathogenesis of IBS. In this section, we will review some of the evolutionary changes that have occurred in IBS. We will discuss how the definition of IBS has changed, consider our evolving strategies to evaluate and diagnose IBS, and finally, provide a brief overview of treatment options for this common disorder.

Unexpectedly low prevalence rates of IBS among adult Israeli Jews

The irritable bowel syndrome (IBS) and other functional bowel disorders (FBDs) are common functional gastrointestinal disorders. The prevalence of IBS using Rome II criteria is generally lower than with previous criteria. The aim of this study was to determine the prevalence of IBS and other FBDs in the adult Israeli Jewish population, which has not been surveyed to date. A telephone survey was conducted on a representative sample of the study population provided by the Israel Ministry of the Interior. IBS and other FBDs were diagnosed by Rome II criteria. The study population was 981 individuals and the overall response rate was 54%. The mean age was 45.0 years and 55% were females. In all, 2.9% had IBS (females: 3.7%, males: 1.8%, P = 0.08). The rate increased to 4.1% when the Rome II diagnostic criteria were amended to include some chronic alternators who are not picked up by the original scoring system. Approximately 26% of the respondents had a functional lower gastrointestinal (GI) disorder (females: 32.1%, males: 17.7%, P < 0.0001). Prevalence rates for IBS among Israeli Jewish adults are lower than rates reported from most countries, despite the high level of stress resulting from Israel's geopolitical circumstances. Possible reasons for this low prevalence are discussed.

Rates of functional bowel disorders among Israeli Bedouins in rural areas compared with those who moved to permanent towns

BACKGROUND & AIMS

Half of Israeli Bedouin society has undergone a transition from nomadic existence to permanent towns, causing cultural and social upheaval. The aim was to compare rates of irritable bowel syndrome (IBS) and functional bowel disorders (FBDs) between Israeli Bedouins still living under rural conditions with those in permanent towns.

METHODS

Interviews were conducted in Arabic by trained Bedouin interviewers at 8 Bedouin clinics. The same interviewers surveyed the 2 sectors under identical sampling and interviewing conditions at the same time. FBDs were diagnosed by Rome II criteria.

RESULTS

One thousand seven hundred fifty-five Bedouins participated, 1018 from permanent towns and 737 from rural areas. Sixty percent were female (58.2% for rural and 62.0% for towns). The mean age was 39.1 +/- 14.1 years (39.0 +/- 14.3 years for towns, 39.2 +/- 13.9 years for rural; P = NS). The mean level of education was 4.3 +/- 5.4 years (4.6 +/- 5.6 years for towns, 3.7 +/- 5.2 years for rural; P < .0001). IBS was diagnosed in 9.4% of town and 5.8% of rural Bedouins ( P < .01). In contrast, rural Bedouins had significantly higher rates of functional abdominal bloating (7.9% vs 2.8%, P < .0001) and a marginally higher rate of functional constipation. Bedouins living in towns attributed their gastrointestinal symptoms to stress more than rural Bedouins did ( P < .05). Stress and poor global feeling of well-being were significant contributors for IBS in logistic regression models for both sectors.

CONCLUSIONS

Bedouins living in permanent towns have significantly higher rates of IBS than rural Bedouins. Although these findings might be associated with the stressful social upheaval that they have undergone, further study is needed to substantiate this point.

Systematic review: the influence of geography and ethnicity in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome has been said to be less common in developing countries compared with western populations. In some case series of irritable bowel syndrome from the Indian subcontinent and Africa, the female predominance typical of western patients did not occur.

AIM AND METHODS

A systematic review was performed on Medline, of community prevalence studies of irritable bowel syndrome, chronic constipation and chronic diarrhoea using standardized criteria, with special reference to the effect of geography and ethnicity, and the gender distribution in different countries.

RESULTS

There is a wide variation, depending in part on the criteria used and differences in diagnostic practices and health care utilization. No convincing evidence emerged of a difference between east and west. Most series, eastern or western showed a female predominance or no gender difference. Several US studies in communities and specific populations suggest that stool frequency is lower, and the prevalence of constipation higher, among Afro-Caribbean Americans compared with white individuals.

CONCLUSIONS

Community studies in multi-racial populations are a useful way of assessing possible ethnic differences in the frequency of irritable bowel syndrome, chronic constipation and diarrhoea, and would additionally present opportunities to relate any ethnic differences to dietary and other environmental factors.

Recognition and treatment of irritable bowel syndrome among women with chronic pelvic pain

OBJECTIVE

We sought to describe irritable bowel syndrome (IBS) treatment among women with chronic pelvic pain.

STUDY DESIGN

We performed a cross-sectional study of new chronic pelvic pain patients between 1993 and 2000 (n = 987). IBS was defined by Rome I criteria. IBS treatment was defined as lower gastrointestinal drugs or referral. Analyses were descriptive and multivariable.

RESULTS

IBS occurred in 35% of patients. In the highest quartile of pain, women with IBS were not more likely to have IBS treatment initiated. In the lowest three quarters of pain, women with IBS were 5.08 times more likely to have IBS treatment initiated. IBS was not diagnosed 40% of the time. IBS treatments were not recommended to 67% of patients with IBS. More than 35% of patients were prescribed narcotics.

CONCLUSION

IBS is not consistently diagnosed and treated even in a pelvic pain clinic. Yet, treatment of IBS may reduce the overall abdominal pain of these patients.

Algorithms to identify colonic ischemia, complications of constipation and irritable bowel syndrome in medical claims data: development and validation

PURPOSE

A challenge in the use of insurance claims databases for epidemiologic research is accurate identification and verification of medical conditions. This report describes the development and validation of claims-based algorithms to identify colonic ischemia, hospitalized complications of constipation, and irritable bowel syndrome (IBS).

METHODS

From the research claims databases of a large healthcare company, we selected at random 120 potential cases of IBS and 59 potential cases each of colonic ischemia and hospitalized complications of constipation. We sought the written medical records and were able to abstract 107, 57, and 51 records, respectively. We established a 'true' case status for each subject by applying standard clinical criteria to the available chart data. Comparing the insurance claims histories to the assigned case status, we iteratively developed, tested, and refined claims-based algorithms that would capture the diagnoses obtained from the medical records. We set goals of high specificity for colonic ischemia and hospitalized complications of constipation, and high sensitivity for IBS.

RESULTS

The resulting algorithms substantially improved on the accuracy achievable from a naïve acceptance of the diagnostic codes attached to insurance claims. The specificities for colonic ischemia and serious complications of constipation were 87.2 and 92.7%, respectively, and the sensitivity for IBS was 98.9%.

CONCLUSIONS

U.S. commercial insurance claims data appear to be usable for the study of colonic ischemia, IBS, and serious complications of constipation.

Review article: epidemiology and quality of life in functional gastrointestinal disorders

The epidemiology and health-related quality of life associated with functional gastrointestinal disorders are reviewed, with particular emphasis on irritable bowel syndrome and functional dyspepsia. The literature supports the significant world-wide prevalence of functional gastrointestinal disorders, including irritable bowel syndrome (IBS), functional dyspepsia and chronic constipation. An increased female prevalence has been demonstrated in most studies in patients with IBS and chronic constipation, but not functional dyspepsia. The female to male ratio appears to be greater in the health care-seeking population than in community populations. However, some differences in the reported general prevalence and gender-related prevalence of functional gastrointestinal disorders may be due to cultural factors and study methodology. A significant health care burden is associated with IBS, with increased out-patient services, abdominal and pelvic surgeries, and gastrointestinal- and non-gastrointestinal-related physician visits and health care costs. Health-related quality of life is impacted significantly in patients with functional gastrointestinal disorders, such as functional dyspepsia and IBS, compared with the general healthy population, as well as patients with other chronic medical conditions, such as gastro-oesophageal reflux disease and asthma. Impaired health-related quality of life has been demonstrated, in particular, in patients with moderate to severe disease seen in referral settings. The health-related quality of life appears to improve in treatment responders, or correlates with symptom improvement, with at least some treatment modalities studied in functional gastrointestinal disorders, but further studies are needed. Predictors of health-related quality of life in patients with functional gastrointestinal disorders include psychosocial factors, such as early adverse life events, and symptoms related to visceral perception, e.g. pain and chronic stress. The presence of extra-intestinal symptoms appears to have a major if not greater impact on health care visits, excess health care costs and health-related quality of life in patients with functional gastrointestinal disorders.

Irritable bowel syndrome in France: a common, debilitating and costly disorder

OBJECTIVE

This epidemiological investigation aims to measure the prevalence of irritable bowel syndrome (IBS) in the general population using the Rome II criteria and to evaluate the medical management including treatments and the impact of IBS on patient life.

METHODS

A nationally representative sample of 20,000 French subjects, aged 18 years and over, were interviewed by SOFRES (French Public Opinion Poll Institute) in May 2001. In a second phase (June/July 2001), a 48-question self-administered questionnaire was given to the subjects who have been selected during the first phase as suffering from IBS (Rome II criteria).

RESULTS

The prevalence of IBS was 4.7% (confidence interval, 4.36-5.04% with 5% risk) with a predominance in women (5.7% versus 3.7%, P < 0.01). The abdominal pain was often longstanding (> 5 years, 50%), intense (43%) and nocturnal (35%). During the most recent painful episode the levels of associated transit problems were almost equally divided between diarrhoea (36%), constipation (29%) and alternate episodes of both (31%). Apart from pain, bloating was given as the most frequent (73%) and most troublesome (24%) symptom. Since the onset, 80% of subjects with IBS had consulted a doctor (90% consulted a general physician, 57% a gastroenterologist, 50% both) and of these, 80% consulted within the previous 12 months. Sixty-seven per cent of subjects underwent additional investigations since the start of their illness (average of 3.4 examinations per patient examined: colonoscopy, 34.1%; laboratory tests, 34%; and abdominal ultrasound, 27.7%). Over the previous 12 months, 8% of the subjects had been admitted to hospital (average length of stay, 6.6 days), 11% of employed subjects had to take time off, 93% of subjects had taken prescribed medication (87%), but 43% of people thought it was ineffective. The effect on daily life was considerable (score, 6.2/10; close to the score for flu, 7/10). Two-thirds of the individuals changed their diet; 54% said it affected their social life and 29% their professional life. Seventy-four per cent of patients trusted their doctor, with a satisfaction index of 63%, but 45% of patients would like to have more information on IBS.

CONCLUSION

This study confirmed that the Rome II criteria detected IBS with a prevalence of 4.7%. The recruited subjects had severe symptoms (frequency, intensity and duration) that had a considerable effect on their daily life. The high level of referrals and initial consultations in all categories and the patient's attitudes towards the illness and its treatment emphasize the relative ineffectiveness of care for patients suffering from IBS.

Prevalence of irritable bowel syndrome (IBS) and variability of diagnostic criteria

OBJECTIVES

The main objectives of this study were to assess whether the use of different definitions of irritable bowel syndrome (IBS) could influence measurements of its prevalence and characterize the patient population fulfilling these different diagnostic criteria.

METHOD

A telephone survey was carried out by contacting 8,221 subjects aged >or=18 Years representative of the French population. A "screening" questionnaire based on three algorithms of IBS classification (Manning, with or without a notion of a minimal duration of symptoms, Rome I and Rome II) was used by specialised inquirers.

RESULTS

Twenty three percent of the subjects interviewed stated that they had suffered from abdominal pain during the previous 12 Months. The prevalence of IBS considerably varied, depending on the diagnostic criteria used: 12% based on Manning criteria without reference to the duration of symptoms; 2.5% if the notion of duration of symptoms was added to the Manning criteria, and 2.1% and 1.1% based on the Rome I and Rome II criteria, respectively (the latter including the same notion of duration). In total, 212 subjects (2.6%) met at least one of the criteria including a minimal duration of symptoms, with a predominance for women (sex-ratio close to 2).

CONCLUSION

The prevalence of IBS is strongly dependent on the classification algorithm employed. The requirement of a minimum duration of symptoms eliminates IBS in a large number of subjects complaining of abdominal disorders. Once these methodological variations were taken into account, the prevalence of IBS in France was found to be comparable to that published in international literature.

Epidemiological features of irritable bowel syndrome in a Turkish urban society

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a widespread functional bowel disorder and its prevalence in Western societies ranges from 3-20%. The present study aimed to determine the prevalence of IBS in eastern Turkey, particularly in urban parts of Elazig where 250 000 people live.

METHODS

Of the 18 primary care centers, four were randomly selected for this study. All individuals (aged >17 years) living around the service area of these health centers were included. A total of 1900 subjects were randomly selected using the personal health records from the primary care centers. The total number of subjects that could be contacted was 1766. A questionnaire with multiple choice questions was applied to the subjects by medical students using the face-to-face technique. Prevalence of IBS and distribution of symptoms were evaluated by the Rome II criteria.

RESULTS

Of the 1766 subjects, 45.4% were male and 54.6% were female. Prevalence of IBS was 5% in males, 7.4% in females and 6.3% overall. The percentage of subjects with IBS in the 17-30 years age group was 26.2%; 52.3% in the 30-50 years age group and 21.6% in the above 50 years age group. Prevalence of IBS was highest (10.2%) in persons who were illiterate and lowest (3.0%) in university graduates. A positive correlation was determined between low economical status and prevalence of IBS (P < 0.05).

CONCLUSION

Although IBS is widely present in Turkey, its prevalence is lower than that reported in Western communities. In the region where this study was carried out, IBS was more prevalent in females and in individuals with low educational and economical status.

Diagnosis and therapy of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gut functional diseases, affecting 10-20% of people worldwide. Although most patients do not seek medical help, the disease accounts for huge costs for both patients and health-care systems and worsens significantly patients' quality of life. Diagnosis is based on the identification of symptoms according to Manning, Rome I and Rome II criteria and exclusion of alarm indicators. IBS symptoms overlap with those of coeliac disease, lactose intolerance, food allergies and bile salt malabsorption. The treatment of IBS is centred on an excellent doctor-patient relationship along with drugs targeting the predominant symptom, especially during exacerbations. Current pharmacological remedies are unsatisfactory due to the high number of patients complaining of lack of response and/or symptom recurrence. Although useful in some IBS patients, the validity of psychotherapy deserves further investigation. A wide array of potentially useful drugs are currently under consideration in pre-clinical trials. A better understanding of the pathogenetic mechanisms underlying IBS may help to develop more effective drugs for this disease.

Irritable bowel syndrome - an evidence-based approach to diagnosis

Irritable bowel syndrome (IBS) represents one of the most common reasons for primary care visits and consultation with a gastroenterologist. It is characterized by abdominal discomfort, bloating and disturbed defecation in the absence of any identifiable physical, radiologic or laboratory abnormalities indicative of organic gastrointestinal disease. IBS is a costly disorder, responsible for significant direct and indirect costs to patients and society. Much of the cost attributed to IBS arises from the time and resources used to establish the diagnosis. Historically IBS has been viewed by many as a diagnosis of exclusion rather than as a primary diagnosis, and many patients with typical symptoms will undergo an extensive array of diagnostic tests and procedures prior to the eventual diagnosis of IBS. Recent reviews addressing the management of such patients have cast doubt on the necessity for this degree of testing. Current best evidence does not support the routine use of blood tests, stool studies, breath tests, abdominal imaging or lower endoscopy in order to exclude organic gastrointestinal disease in patients with typical IBS symptoms without alarm features. Serological testing for celiac sprue in this population may eventually prove useful but validation of studies indicating an increased prevalence of this disease in patients with suspected IBS is needed. The development and refinement of symptom-based criteria defining the clinical syndrome of IBS has greatly facilitated the diagnosis of this condition, which can be confidently diagnosed through the identification of typical symptoms, normal physical examination and the exclusion of alarm features. The presence of alarm features or persistent non-response to symptom-directed therapies should prompt a more detailed diagnostic evaluation dictated by the patient's predominant symptoms.

The interface of psychiatry and irritable bowel syndrome

The interface of psychiatry and irritable bowel syndrome (IBS) is well established, with psychiatric comorbidity approaching 20% to 60%. Anxiety disorders, depressive disorders, and somatoform disorders are the more frequently occurring comorbid conditions. Moreover, psychosocial stressors and history of trauma and abuse play a significant role in the onset and perpetuation of IBS symptoms. The psychiatric management of IBS more effectively uses a collaborative approach between a mental health practitioner and a primary care clinician or gastroenterologist. Psychiatric treatment includes the use of pharmacotherapy with antidepressants or anxiolytics, psychotherapy, and attention to psychosocial stressors. Psychiatric interventions have consistently demonstrated effectiveness in reducing IBS symptoms and improvement of patient functioning.

The burden cost of French patients suffering from irritable bowel syndrome

BACKGROUND

The impact of irritable bowel syndrome (IBS) on health-care resource use in France is evaluated, and explanatory variables determined.

METHODS

A questionnaire comprising socio-demographic characteristics, symptoms, consumption of resources, quality of life and impact of IBS on productivity was administered by telephone to a sample of 253 French adults with IBS recruited from the general population, and diagnosed with IBS using several well-known diagnostic criteria. The medical costs were estimated on a monthly basis and included medication(s), physicians' consultations, investigations and hospitalizations.

RESULTS

Mean age was 48.3 years and 75% of subjects were women (192). Thirty-six percent of subjects had suffered from IBS for more than 10 years; 77% had consulted a general practitioner and 43% a gastroenterologist. Twenty-nine percent of subjects had undergone an investigation and 25% reported hospitalization; 61% of patients reported that they were taking medication. The average monthly medical costs was 71.8 euros (95% CI = [57.6-86.0]) with an asymmetric distribution (median = 28.1 euros) because of a high proportion of subjects (27%) who reported receiving no care at all. The two principal cost components were investigations (39%), and hospitalizations (22%). The highest medical costs were associated with subjects who were very elderly or suffered from severe symptoms (very severe pain), and were correlated with the lowest quality of life scores.

CONCLUSION

IBS has a major impact on resource consumption and the productivity of patients. Determination of the variables to explain medical costs showed that advanced age, severe pain and deterioration in quality of life could be predictive of high medical costs.

Impact of functional gastrointestinal disorders on health-related quality of life: a population-based case-control study

BACKGROUND

The health-related quality of life is impaired in patients with functional gastrointestinal disorders seen in referral centres.

AIM

To determine whether the health-related quality of life is impaired in subjects with functional disorders in the community and whether any differences can be explained by psychological co-morbidity.

METHODS

In a population-based, nested, case-control study, subjects reporting symptoms of either dyspepsia or irritable bowel syndrome and healthy controls were interviewed and completed a battery of psychological measures plus a validated, generic, health-related quality of life measure (Medical Outcomes Study 36-item short form health survey, SF-36). The association between irritable bowel syndrome and dyspepsia and the physical and mental composite scores of SF-36 were assessed with and without adjustment for psychological state.

RESULTS

One hundred and twelve cases (30 dyspepsia, 39 irritable bowel syndrome, 32 dyspepsia and irritable bowel syndrome and 11 gastrointestinal symptoms but not dyspepsia or irritable bowel syndrome) and 110 controls were enrolled. In the unadjusted linear regression models, irritable bowel syndrome (but not dyspepsia) was negatively associated with the physical composite score (P < 0.05); in an adjusted model, the association between the physical health-related quality of life and irritable bowel syndrome was explained by the Symptom Checklist-90 somatization score alone. In unadjusted models, irritable bowel syndrome and dyspepsia were each negatively associated with the mental composite score (P < 0.05). The association between the mental health-related quality of life and dyspepsia remained after adjusting for psychological covariates, but the association between this and irritable bowel syndrome was not significant after adjustment.

CONCLUSIONS

In the community, health-related quality of life is impaired in subjects with irritable bowel syndrome and dyspepsia; however, much of this association can be explained by psychological factors.

The effect of new diagnostic criteria for irritable bowel syndrome on community prevalence estimates

The 'Rome' criteria for irritable bowel syndrome (IBS) have evolved over 15 years with four published versions. The impact of these changes on community prevalence rates is not known. Study aims were to estimate the prevalence of IBS using the four Rome criteria and agreement between Rome II and previous criteria. Questionnaires were mailed to a random sample of Olmsted County, Minnesota residents in 1992. Age- and gender-adjusted prevalence estimates were calculated for Rome II (1999), Rome I (1992), Rome (1990), and Rome (1989) criteria. Per cent agreement and kappa values were calculated to assess agreement. Of 892 eligible subjects, 643 (72%) responded. The age- and gender-adjusted prevalence of IBS was 5.1% [95% confidence interval (CI): 3.1, 7.0], 6.8% (95% CI: 4.7, 8.9), 5.1% (95% CI: 3.2, 7.1) and 27.6% (95% CI: 23.6, 31.5), respectively. In comparison with Rome II criteria, per cent agreement and kappa values were 97.2% and 0.78 (95% CI: 0.69, 0.88), 96.4% and 0.68 (95% CI: 0.55, 0.80), and 79.0% and 0.29 (95% CI: 0.19, 0.40), respectively. Thus, although differences were seen with the older criteria, compared with the Rome I criteria, good agreement was seen and community prevalence estimates were similar with the Rome II criteria.

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.

Novel therapies in the treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is characterised by abnormalities in motility, sensation and perception. It is one of the most common conditions encountered in clinical practice, especially by gastroenterologists. Pharmacological treatment of IBS is aimed at the predominant symptom and recent advances in pathophysiology has opened the door to the development of new compounds that target specific receptors. During this review, the most promising investigational and recently approved drugs will be discussed.

Utility of the Rome I and Rome II criteria for irritable bowel syndrome in U.S. women

OBJECTIVES

Using interview data from a large, community-based sample of American women, we assessed the lifetime prevalence of irritable bowel syndrome (IBS) using questions consistent with the Rome II criteria, determined the sensitivity of Rome I and II in women diagnosed with IBS by their community physician, and identified whether there are differences in the patients identified by Rome I versus II.

METHODS

A geographically diverse national probability sample of women diagnosed with IBS was identified and interviewed by telephone screening of a national, random digit dialing sample of households. A parallel national survey of adult females was conducted to determine the lifetime prevalence of IBS in U.S. women. Screening and interviews were conducted by experienced, female interviewers. IBS was defined by variations on the Rome I/II criteria.

RESULTS

In the national community sample, lifetime IBS prevalence was 5.4% using Rome II. Full interviews were completed in 1,014 IBS patients. In the IBS sample, Rome I was significantly more sensitive than Rome II (84% vs 49%, p < 0.001). There was 47% agreement between Rome I and II. Of patients with IBS by Rome I, 58% met Rome II. Only 17.7% did not meet either Rome I or II.

CONCLUSIONS

Rome I was more sensitive than Rome II in this community sample of female IBS patients. Rome I/II do not necessarily identify the same IBS patients. These findings have important implications for clinical research in IBS patients and raise questions about whether the Rome II criteria are sensitive enough to be useful in clinical practice.

Gender differences in irritable bowel syndrome

In the United States and other Western cultures, a greater number of women seek health care services for symptoms of functional pain disorders, including irritable bowel syndrome, than men. Recent clinical trials indicate that gender differences in responsiveness to drug therapy also occur. Several lines of inquiry have focused on explaining this gender-related difference due to the higher prevalence of these disorders in women. Evidence of a physiologic component is based on gender differences in gastrointestinal transit time, visceral sensitivity, central nervous system pain processing, and specific effects of estrogen and progesterone on gut function. Additional factors may play a role, including gender-related differences in neuroendocrine, autonomic nervous system, and stress reactivity, which are related to bowel function and pain. However, the link between these measures and gut motility or sensitivity remains to be clarified. Psychological characteristics, including somatization, depression, and anxiety as well as a history of sexual abuse, may also contribute to gender-related differences in the prevalence of irritable bowel syndrome. Although gender differences in the therapeutic benefit of serotonergic agents have been observed, less is known about potential differences in responsiveness to nondrug therapies for irritable bowel syndrome.

Irritable bowel syndrome: a little understood organic bowel disease?

Irritable bowel syndrome affects 10% of adults with an unexplained female predominance. Although only a few people see their family doctor, the disease causes reduced quality of life and represents a multi-billion pound health-care problem. The disorder clusters in families, which is possibly because of intra-familial learning and a genetic predisposition. Visceral hypersensitivity is a key feature in most patients. Results of imaging studies of regional cerebral blood flow during rectal distension suggest underlying disturbances of central processing of afferent signals, though this is not unique to the disorder, since it is seen in other chronic pain syndromes. Environmental factors that are strongly implicated in at least some patients include gastrointestinal infection and inflammation and chronic stress. Diagnosis is based on positive symptoms and absence of any alarm indicators. Treatment remains unsatisfactory and hinges on an excellent doctor-patient relationship, with drugs for symptom exacerbations. Cognitive behavioural treatment, psychotherapy, and hypnosis could provide long-lasting benefit in some patients. Tricyclic antidepressants in low doses seem to be the most effective class of drugs for the disorder on the basis of limited data.

The epidemiology of irritable bowel syndrome in North America: a systematic review

OBJECTIVE

The aim of this study was to systematically review published literature about the prevalence, incidence, and natural history of irritable bowel syndrome (IBS) in North America.

METHODS

A computer-assisted search of MEDLINE, EMBASE, and Current Contents/Science Edition databases was performed independently by two investigators. Study selection criteria included: 1) North American population-based sample of adults; 2) objective diagnostic criteria for IBS (i.e., Rome or Manning criteria); and 3) publication in full manuscript form in English. Eligible articles were reviewed in a duplicate and independent manner. Data extracted were converted into individual tables and presented in descriptive form.

RESULTS

The prevalence of IBS in North America ranges from 3% to 20%, with most prevalence estimates ranging from 10% to 15%. The prevalences of diarrhea-predominant and constipation-predominant IBS are both approximately 5%. Published prevalence estimates by gender range from 2:1 female predominance to a ratio of 1:1. Constipation-predominant IBS is more common in female individuals. The prevalence of IBS varies minimally with age. No true population-based incidence studies or natural history studies were found. In one cohort surveyed on two occasions 1 yr apart, 9% of subjects who were free of IBS at baseline reported IBS at follow-up producing an onset rate of 67 per 1000 person-years. In all, 38% of patients meeting criteria for IBS did not meet IBS criteria at 1-yr follow-up.

CONCLUSION

Approximately 30 million people in North America meet the diagnostic criteria for IBS. However, data about the natural history of IBS is quite sparse and renewed efforts should be focused at developing appropriately designed trials of the epidemiology of IBS.

Diagnosis of irritable bowel syndrome

Irritable bowel syndrome (IBS) is the most common disorder seen in gastroenterology practice. It is also a large component of primary care practices. Although the classic IBS symptoms of lower abdominal pain, bloating, and alteration of bowel habits is easily recognizable to most physicians, diagnosing IBS remains a challenge. This is in part caused by the absence of anatomic or physiologic markers. For this reason, the diagnosis of IBS currently needs to be made on clinical grounds. A number of symptom-based diagnostic criteria have been proposed over the last 15 years. The most recent of these, the Rome II criteria, seem to show reasonable sensitivity and specificity in diagnosing IBS. However, the role of the Rome II criteria in clinical practice remains ill defined. A review of the literature shows that, in patients with no alarm symptoms, the Rome criteria have a positive predictive value of approximately 98%, and that additional diagnostic tests have a yield of 2% or less. Diagnostic evaluation should also include a psychosocial assessment specifically addressing any history of sexual or physical abuse because these issues significantly influence management strategies and treatment success.

Irritable bowel syndrome

Irritable bowel syndrome is a biopsychosocial disorder characterized by dysregulation of intestinal motor, sensory, and central nervous system functions. It is associated with significant disability and health-care costs. The traditional diagnostic approach leads to excessive investigation for many patients. A reductionist approach of focusing on evaluation and treatment of a single mechanism is unlikely to prove effective. Identification of the characteristic symptom pattern is the key to cost-effective management. A strong patient-physician relationship is essential for a successful outcome. Optimal outcome is predicated on an individualized treatment plan that integrates pharmacologic and behavioral modalities.

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.

Irritable bowel syndrome: an update on therapeutic modalities

Irritable bowel syndrome (IBS) is the most common condition that a physician faces in the GI clinic. Of the general population, 10 - 25% suffer from symptoms judged to be IBS. The negative impact of this disease includes not only pain, suffering and direct medical expenses but also significant social and job-related consequences. IBS can be the result of dysfunction in any part of the brain-gut axis: alterations in the CNS caused by psychological or other factors, abnormal gastrointestinal motility, or heightened visceral sensations. Diagnosis is based on either the Manning or Rome-II criteria. Education, reassurance and emotional support are the cornerstones of successful treatment. The mainstays of the current therapeutic approach continue to be: stress management strategies, dietary modification entailing addition of dietary fibre and pharmacotherapy. Pharmacotherapy is still limited to treating symptoms. Newer drugs that modulate motility or drugs that modulate visceral sensation may be useful in selected cases. Psychopharmacological agents are useful in the treatment of IBS, especially in those with psychological co-morbidity. Alternative therapies such as homeopathy, acupuncture, special diets, herbal medication and several forms of psychological treatments and hypnotherapy are sought by many patients and are now being offered by physicians as treatment options, either alone or in conjunction with conventional forms of therapy in patients with refractory symptoms.

The irritable bowel syndrome and psychiatric disorders in the community: is there a link?

OBJECTIVE

Psychiatric morbidity is high among patients who present to referral centers with irritable bowel syndrome (IBS). However, few studies have investigated the relationship between psychiatric disturbance and IBS in community samples. We hypothesized that psychiatric disorders are linked to IBS in the general community, but this is influenced by the criteria used to establish a diagnosis of IBS.

METHODS

The data were collected from a birth cohort born in Dunedin (New Zealand) between April 1972 and March 1973. This cohort consisted of 1037 members (52% male), who were assessed at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, and 26 yr. GI symptoms were recorded at age 26 yr, using an abbreviated version of the Bowel Symptom Questionnaire; psychiatric history was obtained at ages 18 and 21 yr, using a modified version of the Diagnostic Interview Schedule.

RESULTS

The prevalence of IBS was 12.7% according to the Manning criteria and 4.3% according to the Rome II criteria. The IBS was not significantly related to a diagnostic history for psychiatric illness overall, nor to a history of anxiety disorders, depressive disorders, and substance dependence. These results were independent of the IBS criteria used; there was no association between psychiatric history and IBS when IBS was defined according to the Manning criteria (p = 0.11 to 0.98) or the Rome criteria (p = 0.18 to 0.92): Rome and Manning criteria subjects did not significantly differ from each other in terms of psychiatric history (p = 0.16 to 0.89).

CONCLUSION

In a cohort of young adults with IBS from New Zealand, IBS appears to not be related to psychiatric disorders.