Serological testing for coeliac disease in patients with symptoms of irritable bowel syndrome: a cost-effectiveness analysis

Identifying the Optimum Strategy for Identifying Adults and Children With Celiac Disease: A Cost-Effectiveness and Value of Information Analysis

OBJECTIVES

Celiac disease (CD) is thought to affect around 1% of people in the United Kingdom, but only approximately 30% are diagnosed. The aim of this work was to assess the cost-effectiveness of strategies for identifying adults and children with CD in terms of who to test and which tests to use.

METHODS

A decision tree and Markov model were used to describe testing strategies and model long-term consequences of CD. The analysis compared a selection of pre-test probabilities of CD above which patients should be screened, as well as the use of different serological tests, with or without genetic testing. Value of information analysis was used to prioritize parameters for future research.

RESULTS

Using serological testing alone in adults, immunoglobulin A (IgA) tissue transglutaminase (tTG) at a 1% pre-test probability (equivalent to population screening) was most cost-effective. If combining serological testing with genetic testing, human leukocyte antigen combined with IgA tTG at a 5% pre-test probability was most cost-effective. In children, the most cost-effective strategy was a 10% pre-test probability with human leukocyte antigen plus IgA tTG. Value of information analysis highlighted the probability of late diagnosis of CD and the accuracy of serological tests as important parameters. The analysis also suggested prioritizing research in adult women over adult men or children.

CONCLUSIONS

For adults, these cost-effectiveness results suggest UK National Screening Committee Criteria for population-based screening for CD should be explored. Substantial uncertainty in the results indicate a high value in conducting further research.

Defining the optimum strategy for identifying adults and children with coeliac disease: systematic review and economic modelling

BACKGROUND

Coeliac disease is an autoimmune disorder triggered by ingesting gluten. It affects approximately 1% of the UK population, but only one in three people is thought to have a diagnosis. Untreated coeliac disease may lead to malnutrition, anaemia, osteoporosis and lymphoma.

OBJECTIVES

The objectives were to define at-risk groups and determine the cost-effectiveness of active case-finding strategies in primary care.

DESIGN

(1) Systematic review of the accuracy of potential diagnostic indicators for coeliac disease. (2) Routine data analysis to develop prediction models for identification of people who may benefit from testing for coeliac disease. (3) Systematic review of the accuracy of diagnostic tests for coeliac disease. (4) Systematic review of the accuracy of genetic tests for coeliac disease (literature search conducted in April 2021). (5) Online survey to identify diagnostic thresholds for testing, starting treatment and referral for biopsy. (6) Economic modelling to identify the cost-effectiveness of different active case-finding strategies, informed by the findings from previous objectives.

DATA SOURCES

For the first systematic review, the following databases were searched from 1997 to April 2021: MEDLINE® (National Library of Medicine, Bethesda, MD, USA), Embase® (Elsevier, Amsterdam, the Netherlands), Cochrane Library, Web of Science™ (Clarivate™, Philadelphia, PA, USA), the World Health Organization International Clinical Trials Registry Platform ( WHO ICTRP ) and the National Institutes of Health Clinical Trials database. For the second systematic review, the following databases were searched from January 1990 to August 2020: MEDLINE, Embase, Cochrane Library, Web of Science, Kleijnen Systematic Reviews ( KSR ) Evidence, WHO ICTRP and the National Institutes of Health Clinical Trials database. For prediction model development, Clinical Practice Research Datalink GOLD, Clinical Practice Research Datalink Aurum and a subcohort of the Avon Longitudinal Study of Parents and Children were used; for estimates for the economic models, Clinical Practice Research Datalink Aurum was used.

REVIEW METHODS

For review 1, cohort and case-control studies reporting on a diagnostic indicator in a population with and a population without coeliac disease were eligible. For review 2, diagnostic cohort studies including patients presenting with coeliac disease symptoms who were tested with serological tests for coeliac disease and underwent a duodenal biopsy as reference standard were eligible. In both reviews, risk of bias was assessed using the quality assessment of diagnostic accuracy studies 2 tool. Bivariate random-effects meta-analyses were fitted, in which binomial likelihoods for the numbers of true positives and true negatives were assumed.

RESULTS

People with dermatitis herpetiformis, a family history of coeliac disease, migraine, anaemia, type 1 diabetes, osteoporosis or chronic liver disease are 1.5-2 times more likely than the general population to have coeliac disease; individual gastrointestinal symptoms were not useful for identifying coeliac disease. For children, women and men, prediction models included 24, 24 and 21 indicators of coeliac disease, respectively. The models showed good discrimination between patients with and patients without coeliac disease, but performed less well when externally validated. Serological tests were found to have good diagnostic accuracy for coeliac disease. Immunoglobulin A tissue transglutaminase had the highest sensitivity and endomysial antibody the highest specificity. There was little improvement when tests were used in combination. Survey respondents (n = 472) wanted to be 66% certain of the diagnosis from a blood test before starting a gluten-free diet if symptomatic, and 90% certain if asymptomatic. Cost-effectiveness analyses found that, among adults, and using serological testing alone, immunoglobulin A tissue transglutaminase was most cost-effective at a 1% pre-test probability (equivalent to population screening). Strategies using immunoglobulin A endomysial antibody plus human leucocyte antigen or human leucocyte antigen plus immunoglobulin A tissue transglutaminase with any pre-test probability had similar cost-effectiveness results, which were also similar to the cost-effectiveness results of immunoglobulin A tissue transglutaminase at a 1% pre-test probability. The most practical alternative for implementation within the NHS is likely to be a combination of human leucocyte antigen and immunoglobulin A tissue transglutaminase testing among those with a pre-test probability above 1.5%. Among children, the most cost-effective strategy was a 10% pre-test probability with human leucocyte antigen plus immunoglobulin A tissue transglutaminase, but there was uncertainty around the most cost-effective pre-test probability. There was substantial uncertainty in economic model results, which means that there would be great value in conducting further research.

LIMITATIONS

The interpretation of meta-analyses was limited by the substantial heterogeneity between the included studies, and most included studies were judged to be at high risk of bias. The main limitations of the prediction models were that we were restricted to diagnostic indicators that were recorded by general practitioners and that, because coeliac disease is underdiagnosed, it is also under-reported in health-care data. The cost-effectiveness model is a simplification of coeliac disease and modelled an average cohort rather than individuals. Evidence was weak on the probability of routine coeliac disease diagnosis, the accuracy of serological and genetic tests and the utility of a gluten-free diet.

CONCLUSIONS

Population screening with immunoglobulin A tissue transglutaminase (1% pre-test probability) and of immunoglobulin A endomysial antibody followed by human leucocyte antigen testing or human leucocyte antigen testing followed by immunoglobulin A tissue transglutaminase with any pre-test probability appear to have similar cost-effectiveness results. As decisions to implement population screening cannot be made based on our economic analysis alone, and given the practical challenges of identifying patients with higher pre-test probabilities, we recommend that human leucocyte antigen combined with immunoglobulin A tissue transglutaminase testing should be considered for adults with at least a 1.5% pre-test probability of coeliac disease, equivalent to having at least one predictor. A more targeted strategy of 10% pre-test probability is recommended for children (e.g. children with anaemia).

FUTURE WORK

Future work should consider whether or not population-based screening for coeliac disease could meet the UK National Screening Committee criteria and whether or not it necessitates a long-term randomised controlled trial of screening strategies. Large prospective cohort studies in which all participants receive accurate tests for coeliac disease are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019115506 and CRD42020170766.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 44. See the NIHR Journals Library website for further project information.

Is mass screening for coeliac disease a wise use of resources? A health economic evaluation

Background

Living with undiagnosed symptomatic coeliac disease is connected with deteriorated health, and persons with coeliac disease often wait a long time for their diagnosis. A mass screening would lower the delay, but its cost-effectiveness is still unclear. Our aim was to determine the cost-effectiveness of a coeliac disease mass screening at 12 years of age, taking a life course perspective on future benefits and drawbacks.

Methods

The cost-effectiveness was derived as cost per quality-adjusted life-year (QALY) using a Markov model. As a basis for our assumptions, we mainly used information from the Exploring the Iceberg of Celiacs in Sweden (ETICS) study, a school-based screening conducted in 2005/2006 and 2009/2010, where 13,279 12-year-old children participated and 240 were diagnosed with coeliac disease, and a study involving members of the Swedish Coeliac Association with 1031 adult participants.

Results

The cost for coeliac disease screening was 40,105 Euro per gained QALY. Sensitivity analyses support screening based on high compliance to a gluten-free diet, rapid progression from symptom-free coeliac disease to coeliac disease with symptoms, long delay from celiac disease with symptoms to diagnosis, and a low QALY score for undiagnosed coeliac disease cases.

Conclusions

A coeliac disease mass screening is cost-effective based on the commonly used threshold of 50,000 Euro per gained QALY. However, this is based on many assumptions, especially regarding the natural history of coeliac disease and the effects on long-term health for individuals with coeliac disease still eating gluten.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01737-1.

ACG Clinical Guideline: Management of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a highly prevalent, chronic disorder that significantly reduces patients' quality of life. Advances in diagnostic testing and in therapeutic options for patients with IBS led to the development of this first-ever American College of Gastroenterology clinical guideline for the management of IBS using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Twenty-five clinically important questions were assessed after a comprehensive literature search; 9 questions focused on diagnostic testing; 16 questions focused on therapeutic options. Consensus was obtained using a modified Delphi approach, and based on GRADE methodology, we endorse the following: We suggest that a positive diagnostic strategy as compared to a diagnostic strategy of exclusion be used to improve time to initiating appropriate therapy. We suggest that serologic testing be performed to rule out celiac disease in patients with IBS and diarrhea symptoms. We suggest that fecal calprotectin be checked in patients with suspected IBS and diarrhea symptoms to rule out inflammatory bowel disease. We recommend a limited trial of a low fermentable oligosaccharides, disacchardies, monosaccharides, polyols (FODMAP) diet in patients with IBS to improve global symptoms. We recommend the use of chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms. We recommend the use of rifaximin to treat global IBS with diarrhea symptoms. We suggest that gut-directed psychotherapy be used to treat global IBS symptoms. Additional statements and information regarding diagnostic strategies, specific drugs, doses, and duration of therapy can be found in the guideline.

Celiac Disease Screening for High-Risk Groups: Are We Doing It Right?

Celiac disease (CD) is an immune-mediated enteropathy triggered by dietary ingestion of gluten in genetically susceptible patients. CD is often diagnosed by a "case-finding" approach of symptomatic patients. In recent times, the diagnostic paradigm has shifted to investigate patients who may be asymptomatic, but are at high risk of developing CD due to shared genetic susceptibilities. These high-risk groups include first-degree relatives of CD patients and patients with Type 1 diabetes mellitus, autoimmune thyroid disease, Down's syndrome, and Turner syndrome. Moreover, CD is often diagnosed as the cause of iron deficiency anemia or unexplained chronic diarrhea. Although screening for CD with serological tests is not recommended for the general population, it should be considered in these special populations. In this review, we explore screening for CD among high-risk groups in light of recent research and development in the CD arena.

Cost Effectiveness of Biomarker Tests for Irritable Bowel Syndrome With Diarrhea: A Framework for Payers

BACKGROUND & AIMS

Diagnosis of diarrhea-predominant irritable bowel syndrome (IBS-D) relies on the Rome IV symptom-based criteria, which are imperfect for separating functional vs organic disease. Biomarker tests for IBS-D might be added to symptom data to allow clinicians to make more accurate and precise diagnoses in a cost-effective manner. We tested the economic consequences of using a range of hypothetical IBS-D biomarkers, and explored at what cost and level of accuracy a biomarker becomes cost effective. We produced a framework for payers to evaluate the return on an investment of implementing IBS-D biomarkers of varying accuracy and cost.

METHODS

We used decision analysis software to evaluate a hypothetical cohort of patients who met Rome IV criteria for IBS-D. We conducted cost-utility and budget impact analyses of 2 competing approaches: usual care or an IBS biomarker-based diagnostic approach. Patients in the usual care group received empiric IBS treatment; non-responders received additional diagnostic tests for organic disease. In the group evaluated with a biomarker test, those with a positive result received IBS treatment before additional diagnostic analyses, whereas patients with a negative result underwent upfront diagnostic testing. Outcomes were incremental cost per quality-adjusted life year gained (third-party payer perspective) and incremental per-member per-month cost.

RESULTS

In the base-case analysis, using a willingness-to-pay threshold of $100,000/quality-adjusted life year, we found that biomarkers are not cost effective when the biomarker test costs more than $846, even if the test is 100% accurate in detecting IBS-D. In probabilistic analysis using 1,000 simulations, most trials (75% or more) show that the biomarker-based diagnostic approach is cost effective above the following accuracy thresholds: a $100 biomarker test with 51% accuracy, a $200 test with 57% accuracy, a $300 test with 63% accuracy, a $400 test with 69% accuracy, a $500 test with 76% accuracy, a $600 test with 82% accuracy, a $700 test with 89% accuracy, and a $800 test with 94% accuracy.

CONCLUSIONS

In decision analysis of a hypothetical cohort of patients who met Rome IV criteria for IBS-D, we identified cost and accuracy thresholds that can guide investigators and payers as they develop, validate, price, and/or reimburse IBS-D biomarker tests for use in everyday clinical practice.

Review article: coeliac disease in later life must not be missed

BACKGROUND

The presenting symptoms of coeliac disease are often subtle and the diagnosis is frequently delayed or overlooked. Therefore, especially elderly patients may be denied the benefits conferred by gluten free diet which can be dramatically life-changing.

AIM

To review the occurrence, clinical features, diagnosis and management in coeliac patients detected later in life.

METHODS

To review manuscripts concerned with coeliac disease in the elderly and to derive subgroups of elderly people from publications on the disorder.

RESULTS

Approximately a quarter of all diagnoses are now made at the age of 60 years or more and a fifth at 65 years or over. About 4% are diagnosed at 80 years or above. Around 60% remain undetected, since their symptoms are often subtle: tiredness, indigestion, reduced appetite. Good compliance with gluten free diet, resolution of symptoms and improvement in laboratory indices can be achieved in over 90% of patients.

CONCLUSIONS

Coeliac disease not uncommonly presents for the first time in older patients and is an important diagnosis to make.

Prevalence of celiac disease in adult Chinese patients with diarrhea-predominant irritable bowel syndrome: A prospective, controlled, cohort study

OBJECTIVE

Celiac disease is a chronic inflammatory enteropathy with a symptom spectrum similar to that of irritable bowel syndrome (IBS). It is a common but largely undiagnosed condition in the Western countries. However, it is extremely rare among Chinese individuals, and few studies have investigated its prevalence in China. The aim was to determine the prevalence of celiac disease in patients with IBS who were diagnosed using the Rome III criteria in a single center of northern China.

METHODS

This was a single-center, prospective, controlled cohort study performed in Qilu Hospital involving 246 patients with IBS and 246 healthy controls. Blood samples were drawn to assess serum tissue transglutaminase immunoglobulin A (tTg-IgA). Patients with a positive or equivocal tTg-IgA (≥15 U/mL) were subjected to probe-based confocal laser endomicroscopy (pCLE) and duodenal biopsy to confirm celiac disease.

RESULTS

Altogether 12 (4.9%) patients with IBS and two (0.8%) healthy controls were positive or equivocal for serum tTg-IgA. Of these, five patients with IBS underwent pCLE and a targeted biopsy; all were histopathologically found to have celiac disease, although one was eventually diagnosed with lymphoma. After implementation of a gluten-free diet, seven patients serologically positive for IBS showed clinical improvement, thus our study illustrated a minimum prevalence of 2.85% of celiac disease among patients with IBS in our center.

CONCLUSIONS

Celiac disease is not rare in Chinese individuals, particularly among those with IBS. Therefore, it should receive higher attention in clinical practice in China.

Screening for Celiac Disease in Irritable Bowel Syndrome: An Updated Systematic Review and Meta-analysis

OBJECTIVES

Celiac disease (CD) and irritable bowel syndrome (IBS) share similar symptoms, leading to confusion between the two and diagnostic delay. International guidelines recommend screening individuals with IBS for CD, via serological testing. However, studies published recently have cast doubt on the utility of this. We updated a previous meta-analysis examining this issue.

METHODS

MEDLINE, EMBASE, and EMBASE Classic were searched through to May 2016. Eligible studies recruited adults with IBS according to symptom-based criteria, physician's opinion, or questionnaire data. Tests for CD included IgA-class antigliadin antibodies (AGA), endomysial antibodies (EMA), tissue transglutaminase antibodies (tTG), or duodenal biopsies following positive serology. The proportion of individuals meeting criteria for IBS testing positive for CD was combined to give a pooled prevalence for all studies, and compared between cases with IBS and, healthy controls without (where reported), using an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

There were 36 eligible studies, recruiting 15,256 individuals, of whom 9,275 (60.8%) met criteria for IBS. Pooled ORs for positive IgA AGAs, EMA and/or tTG, and biopsy-proven CD in IBS subjects vs. controls were 3.21 (95% CI 1.55-6.65), 2.75 (95% CI 1.35-5.61), and 4.48 (95% CI 2.33-8.60), respectively. There was no increase in ORs for any test for CD among cases with IBS in North American studies, and results were inconsistent in population-based studies. The prevalence of biopsy-proven CD was significantly higher across all subtypes of IBS. Limitations included heterogeneity in some analyses, and few North American studies.

CONCLUSIONS

Overall, prevalence of positive celiac serology and biopsy-proven CD was significantly higher in subjects with symptoms suggestive of IBS vs. healthy controls. However, the utility of screening for CD in individuals with suspected IBS in North America or in the community is less clear.

The prevalence of celiac disease in patients with irritable bowel syndrome and its subtypes

Introduction

Irritable bowel syndrome (IBS) and celiac disease (CD) share some gastrointestinal symptoms. Celiac disease should be considered in a differential diagnosis of IBS.

Aim

To estimate the prevalence of predispositions to CD in patients with IBS and its subtypes.

Material and methods

The study included 48 patients (40 women, 8 men; average age: 41.1 ±14.6 years) with IBS, and a control group: 20 healthy volunteers. All participants completed a questionnaire on their current gastrointestinal symptoms and had a blood sample taken to determine the HLA-DQ2/DQ8 antigens and serum concentration of anti-tTG IgA and anti-DGP IgA and IgG.

Results

The presence of HLA-DQ2 or DQ8 was found in 50% of patients (n = 24) with IBS. In the control group the presence of HLA-DQ2 was found in 4 (20%) patients and nobody had HLA-DQ8. Increased levels of anti-tTG IgA were found in 5 (10.42%) patients with IBS, anti-DGP in 4 (8.33%), and anti-DGP IgG in 3 (6.25%). In the control group positive test result for anti-tTG was found in 2 (10%) patients; nobody had elevated anti-DGP IgA or IgG. A concomitant positive result of genetic testing and any elevated serum antibodies specific to CD was found in 12.5% of IBS patients (n = 6) and in none of the control group.

Conclusions

Patients with IBS, regardless of the subtype, significantly more often than healthy controls have the predisposing genetic factors (HLA-DQ2/DQ8) underlying the development of CD.

The incidence of other gastroenterological disease following diagnosis of irritable bowel syndrome in the UK: a cohort study

Background

Guidelines recommend Irritable Bowel Syndrome (IBS) diagnosis and management in primary care with minimal investigations; however little evidence exists regarding risk of organic gastrointestinal conditions following diagnosis of IBS and how such risks vary over the long term. This study assesses excess incidence of coeliac disease, inflammatory bowel disease (IBD) and colorectal cancer (CRC) and variation with age and time after IBS diagnosis.

Methods

IBS patients and controls were identified within the UK Clinical Practice Research Dataset. Incidence rates were calculated and stratified by age and time since IBS diagnosis with incident rate ratios generated.

Results

Fifteen years after IBS diagnosis there is a significant cumulative excess incidence of coeliac disease, IBD and CRC in IBS of 3.7% compared to 1.7% in controls. For every 10000 patient years, IBS patients experienced an additional 4 diagnoses of coeliac disease, 13 of IBD and 4 CRCs. In each condition peak excess incidence was in the 6 months following diagnosis. After one year, increased incidence of coeliac disease remained consistent without variation by age. IBD incidence fell slowly, with higher rates in those under 30. CRC incidence was increased only in patients aged 30 to 74 during the first 5 years.

Conclusion

Some IBS patients later receive organic gastrointestinal diagnoses, with the early excess incidence likely detected during diagnostic investigation at the time of IBS diagnosis. More than 5 years after IBS diagnosis there is no increased risk of CRC compared to the general population, but a small excess risk of coeliac disease and IBD persists. Overall, though our findings provide reassurance that non-specialists, especially those in primary care, are unlikely to be missing an organic condition in the majority of their patients. This suggests that current guidelines suggesting avoidance of universal referral for these patients are appropriate.

Pediatric IBS: an overview on pathophysiology, diagnosis and treatment

Irritable bowel syndrome (IBS) is a common disorder in children and adults. The pathogenesis and pathophysiology of IBS remains incompletely understood. The biopsychosocial model, which conceptualizes chronic pain as a dysregulation of the gut-brain-homeostasis with peripheral and central factors mutually influencing each other, is the most accepted framework to explain IBS. Twin and family aggregation studies suggest a genetic component that does not exclusively explain the higher prevalence of IBS in certain families. Social learning (environmental factors) and maladaptive coping predispose children to develop IBS with greater disability and more frequent medical consultations. Early-life events constitute an additional risk factor for the development of IBS and other functional gastrointestinal disorders (FGIDs). Children with a history of cow's milk protein hypersensitivity or abdominal surgeries have a higher prevalence of IBS and other FGIDs years later. IBS frequently follows an episode of acute gastrointestinal inflammation (infectious or non-infectious). This article discusses the importance, known pathophysiological mechanisms, clinical approach, and evidence-based therapeutic options for the management of IBS in children and adolescents.

Functional disorders of the gastrointestinal tract: Cost effectiveness review

BACKGROUND

The project aim was to review current cost-effectiveness research for each functional gastrointestinal disorder, as defined by the Rome III classification system.

METHODS

Biomedical databases were searched for articles with the functional gastrointestinal disorders and their pseudonyms included in the title, abstract, or medical subject headings, plus the terms benefit, cost, effectiveness, outcomes, test, utility, or utilization in any search field.

RESULTS

Highly prevalent conditions such as dyspepsia and irritable bowel syndrome have advanced cost-effectiveness analyses including cost-utility studies that have helped support current management guidelines. The rarer functional gastrointestinal disorders have few or no published cost-effectiveness analyses, but the Rome III classification system provides a framework for identifying the specific cost data or outcomes measures available or needed for future research.

CONCLUSIONS

The Rome process has provided a useful system for defining the functional gastrointestinal disorders and identifying specific clinical questions to be examined using cost-effectiveness analysis techniques.

Frequent delay of coeliac disease diagnosis in symptomatic patients with type 1 diabetes mellitus: clinical and genetic characteristics

BACKGROUND

Patients with type 1 diabetes mellitus (T1DM) are more prone to develop other auto-immune diseases, including coeliac disease (CD). Paediatric patients with T1DM are screened for CD, whereas in adult T1DM patients screening programs for CD are not standardised. The aim of this study was to investigate clinical and genetic characteristics of patients with both diagnoses so as to lead to better detection of CD in adult patients with T1DM.

METHODS

We studied 118 patients with both T1DM and CD identified in The Netherlands. We retrospectively collected data on sex distribution, age of onset of T1DM, age of CD diagnosis, CD complaints, duration of CD complaints before CD diagnosis, family history of CD or T1DM, comorbidity and HLA-DQ type.

RESULTS

Thirty-three percent of T1DM+CD patients reported CD related complaints for at least 5 years before CD diagnosis. Two peaks in the age of CD diagnosis in T1DM patients were observed: around 10 and 45 years of age. Women were diagnosed with CD at a younger age than men (median 25 years (IQR 9-38) versus 39 (12-55) years, respectively, P<0.05).

CONCLUSION

A delay of CD diagnosis is frequently found in adult T1DM patients and two peaks in the age of CD diagnosis are present in T1DM patients. This observational study emphasises that more frequent screening for CD in particularly adult T1DM patients is required, preferably by a 5 years interval.

Gluten-free diet in gluten-related disorders

A gluten-free diet (GFD) is recommended for all patients with coeliac disease (CD). The spectrum of gluten-related disorders in the early 1980s was simple: CD and dermatitis herpetiformis. In the last few years, wheat allergy, gluten ataxia and noncoeliac gluten sensitivity have become new gluten-related topics. Adherence to GFDs in CD is limited and factors influencing adherence are poorly understood. Noncoeliac gluten sensitivity has stimulated the GFD food industry not only in Australia but all over the world. This article provides an overview of GFD in daily practice.

Are we diagnosing too many people with coeliac disease?

This review will try to address the question of whether we are diagnosing too many people with coeliac disease. The key reasons for diagnosing coeliac disease may be that it is a common condition affecting up to 1% of the adult population. Delays in diagnosis are common. The average time delay reported by Coeliac UK (National Medical Patient Charity), for patients with symptoms prior to the diagnosis being made is 13 years. For every adult case detected, it is estimated that there are eight cases not detected. Patients with coeliac disease have an associated morbidity and mortality. In addition, quality of life studies suggest that the majority of patients benefit from a gluten-free diet (GFD). Furthermore, the GFD reduces or alleviates the risk of the associated complications. All of these facts could even be used to support the argument for screening! However, conversely the tests for coeliac disease are not 100% sensitive and specific. In addition, we do not know whether patients with milder symptoms will derive less benefit from treatment and are at less risk of complications. Furthermore, evidence presented in this review suggests that actual outcomes for screening studies in an adult population have revealed poor uptake and subsequently difficulties with adherence. What little published data that are available also infers that individuals recognised through screening programmes could have been detected if carefully questioned for symptoms. There is evidence to suggest that diagnosing celiac disease is cost-effective and that the diagnostic costs are offset by reduced medical expenditures, reduced hospital and general practice attendances, but this view depends on the population prevalence of coeliac disease. We believe on the basis of the evidence presented in this review that we are not diagnosing too many adults with coeliac disease. However, the authors consider case-finding with a low threshold for serological testing to be the optimal approach. If you look for coeliac disease you will find it.

The Irritable Bowel Syndrome Outcome Study (IBSOS): rationale and design of a randomized, placebo-controlled trial with 12 month follow up of self- versus clinician-administered CBT for moderate to severe irritable bowel syndrome

Irritable bowel syndrome is a common, oftentimes disabling, gastrointestinal disorder whose full range of symptoms has no satisfactory medical or dietary treatment. One of the few empirically validated treatments includes a specific psychological therapy called cognitive behavior therapy which, if available, is typically administered over several months by trained practitioners in tertiary care settings. There is an urgent need to develop more efficient versions of CBT that require minimal professional assistance but retain the efficacy profile of clinic based CBT. The Irritable Bowel Syndrome Outcome Study (IBSOS) is a multicenter, placebo-controlled randomized trial to evaluate whether a self-administered version of CBT is, at least as efficacious as standard CBT and more efficacious than an attention control in reducing core GI symptoms of IBS and its burden (e.g. distress, quality of life impairment, etc.) in moderately to severely affected IBS patients. Additional goals are to assess, at quarterly intervals, the durability of treatment response over a 12 month period; to identify clinically useful patient characteristics associated with outcome as a way of gaining an understanding of subgroups of participants for whom CBT is most beneficial; to identify theory-based change mechanisms (active ingredients) that explain how and why CBT works; and evaluate the economic costs and benefits of CBT. Between August 2010 when IBSOS began recruiting subjects and February 2012, the IBSOS randomized 171 of 480 patients. Findings have the potential to improve the health of IBS patients, reduce its social and economic costs, conserve scarce health care resources, and inform evidence-based practice guidelines.

The chronic gastrointestinal consequences associated with campylobacter

Campylobacteriosis is a leading cause of acute infectious diarrhea in the developing world, where it causes considerable mortality, and in developed countries, where it accounts for significant healthcare and other costs. Evidence has emerged from basic science, clinical, and epidemiological domains that suggests that Campylobacter infection is not limited to acute illness but is also involved in the development of well-described extraintestinal sequelae, such as the Guillain-Barré syndrome and reactive arthritis, and may also contribute to the pathogenesis of chronic gastrointestinal conditions. This review will focus on the role of Campylobacter infection as a risk factor for the development of chronic gastrointestinal sequelae, such as functional gastrointestinal disorders, with which irritable bowel syndrome has been most frequently associated, inflammatory bowel disease, and celiac disease.

Resource use and costs associated with coeliac disease before and after diagnosis in 3,646 cases: results of a UK primary care database analysis

BACKGROUND

Despite the considerable health impact of coeliac disease (CD), reliable estimates of the impact of diagnosis on health care use and costs are lacking.

AIMS

To quantify the volume, type and costs, in a United Kingdom primary care setting, of healthcare resources used by individuals diagnosed with CD up to ten years before and after diagnosis, and to estimate medical costs associated with CD.

METHODS

A cohort of 3,646 CD cases and a parallel cohort of 32,973 matched controls, extracted from the General Practice Research Database (GPRD) over the period 1987-2005 were used i) to evaluate the impact of diagnosis on the average resource use and costs of cases; ii) to assess direct healthcare costs due to CD by comparing average resource use and costs incurred by cases vs. controls.

RESULTS

Average annual healthcare costs per patient increased by £310 (95% CI £299, £320) after diagnosis. CD cases experienced higher healthcare costs than controls both before diagnosis (mean difference £91; 95% CI: £86, £97) and after diagnosis (mean difference £354; 95% CI: £347, £361). These differences were driven mainly by higher test and referral costs before diagnosis, and by increased prescription costs after diagnosis.

CONCLUSIONS

This study shows significant additional primary care costs associated with coeliac disease. It provides novel evidence that will assist researchers evaluating interventions in this area, and will challenge policymakers, clinicians, researchers and the public to develop strategies that maximise the health benefits of the resources associated with this disease.

Frequency of celiac disease in adult patients with typical or atypical malabsorption symptoms in isfahan, iran

Aim. Atypical presentations of celiac disease (CD) have now been shown to be much more common than classical (typical) form. We evaluated the frequency of CD among adult patients with typical or atypical symptoms of CD. Materials and Methods. Patients referred to two outpatient gastroenterology clinics in Isfahan (IRAN) were categorized into those with typical or atypical symptoms of CD. IgA antitissue transglutaminase antibody was assessed and followed by duodenal biopsy. In patients for whom endoscopy was indicated (independent of the serology), duodenal biopsy was taken. Histopathological changes were assessed according to the Marsh classification. Results. During the study period, 151 and 173 patients with typical and atypical symptoms were evaluated (mean age = 32.8 ± 12.6 and 35.8 ± 14.8 years, 47.0% and 56.0% female, resp.). Frequency of CD in patients with typical and atypical symptoms was calculated, respectively, as 5.9% (9/151) and 1.25% (3/173) based on positive serology and pathology. The overall frequency was estimated as at least 9.2% (14/151) and 4.0% (7/173) when data of seronegative patients were also considered. Conclusions. CD is more frequent among patients with typical symptoms of malabsorption and these patients should undergo duodenal biopsy, irrespective of the serology. In patients with atypical symptoms, serological tests should be performed followed by endoscopic biopsy, and routine duodenal biopsy is recommended when endoscopic evaluation is indicated because of symptoms.

Celiac disease diagnosis and management: a 46-year-old woman with anemia

Celiac disease is one of the most prevalent autoimmune gastrointestinal disorders, but as the case of Ms J illustrates, diagnosis is often delayed or missed. Based on serologic studies, the prevalence of celiac disease in many populations is estimated to be approximately 1% and has been increasing steadily over the last 50 years. Evaluation for celiac disease is generally straightforward and uses commonly available serologic tests; however, the signs and symptoms of celiac disease are nonspecific and highly heterogeneous, making diagnosis difficult. Although celiac disease is often considered a mild disorder treatable with simple dietary changes, in reality celiac disease imparts considerable risks, including reduced bone mineral density, impaired quality of life, and increased overall mortality. In addition, a gluten-free diet is highly burdensome and can profoundly affect patients and their families. For these reasons, care of individuals with celiac disease requires prompt diagnosis and ongoing multidisciplinary management.

The prevalence of celiac disease among patients with nonconstipated irritable bowel syndrome is similar to controls

BACKGROUND & AIMS

Guidelines recommend that patients with symptoms of nonconstipated irritable bowel syndrome (NC-IBS) undergo testing for celiac disease (CD). We evaluated the prevalence of CD antibodies, and biopsy confirmed CD among patients with NC-IBS in a large US population.

METHODS

In a study conducted at 4 sites, from 2003 to 2008, we compared data from 492 patients with symptoms of NC-IBS to 458 asymptomatic individuals who underwent colonoscopy examinations for cancer screening or polyp surveillance (controls). All participants provided blood samples for specific and nonspecific CD-associated antibodies. Additionally, patients with IBS were analyzed for complete blood cell counts, metabolic factors, erythrocyte sedimentation rates, and levels of C-reactive protein and thyroid-stimulating hormone. Any subjects found to have CD-associated antibodies were offered esophagogastroduodenoscopy and duodenal biopsy analysis.

RESULTS

Of patients with NC-IBS, 7.3% had abnormal results for CD-associated antibodies, compared with 4.8% of controls (adjusted odds ratio, 1.49; 95% confidence interval: 0.76-2.90; P=.25). Within the NC-IBS group, 6.51% had antibodies against gliadin, 1.22% against tissue transglutaminase, and 0.61% against endomysium (P>.05 vs controls for all antibodies tested). CD was confirmed in 0.41% of patients in the NC-IBS group and 0.44% of controls (P>.99).

CONCLUSIONS

Although CD-associated antibodies are relatively common, the prevalence of CD among patients with NC-IBS is similar to that among controls in a large US population. These findings challenge recommendations to routinely screen patients with NC-IBS for CD. More than 7% of patients with NC-IBS had CD-associated antibodies, suggesting that gluten sensitivity might mediate IBS symptoms; further studies are needed.

Is it time to screen for adult coeliac disease?

To meet the principles of screening as described by Wilson and Jungner a disease must be common, a significant health burden, detectable and treatable. The key lies in the early detection and alteration of the natural history of disease. Coeliac disease affects 1 in 100 people. Despite this patients frequently have delays in diagnosis or may remain undetected. There is an associated morbidity and mortality which can be effectively treated by simple means of a gluten-free diet. For these reasons coeliac disease has been suggested as appropriate for mass screening. However, there are caveats to this: a complex clinical spectrum, a natural history that is imperfectly understood, overestimation of morbidity and mortality, poor adherence to treatment, and costs of service provision may argue against the time being right for mass screening. This review article provides the most contemporary overview and reference base to allow any clinician to understand the benefits or limitations of a screening programme for adult coeliac disease.

Parents' willingness to pay for coeliac disease screening of their child

OBJECTIVE

The aim of this study is to determine Swedish parents' willingness to pay (WTP) for coeliac disease (CD) screening of their child.

SUBJECTS AND METHODS

CD screening was undertaken involving 10,041 12-year-old children, with 7567 (75%) agreeing to participate. Blood samples from the children were analysed for CD serological markers. Parents received a questionnaire including a scenario describing the health-related risks of having CD and screening and diagnostic procedures. Parents were also asked whether they were willing to pay for CD screening, should this not be offered free of charge, and, if so, what their maximum WTP would be. Their WTP was compared with the average cost per child for the screening and case ascertainment procedures.

RESULTS

The questionnaire was answered by 6524 parents, and of 6057 valid responses 63% stated that they were willing to pay something. The mean WTP was 79 EUR and the median 10 EUR. The average cost per child for the screening and case ascertainment procedures was 47 EUR, which 23% of the parents stated they were willing to pay. Parents' WTP increased with higher education and income, and with child symptoms that may indicate CD.

CONCLUSIONS

Swedish parents' WTP for school-based CD screening of their child was higher than the average cost per child; however, only a minority of the parents were willing to pay that amount.

The role of diagnostic testing in irritable bowel syndrome

This article discusses the diagnostic criteria and processes applicable to irritable bowel syndrome (IBS). The authors describe the various diagnostic criteria with a focus on the Rome criteria for IBS and the judicious application of historical information such as alarm features and the yield of various diagnostic modalities such as blood, stool, breath, and endoscopic tests.

The prevalence of celiac disease in patients fulfilling Rome III criteria for irritable bowel syndrome

BACKGROUND AND AIMS

Celiac disease shares several symptoms which constitute some of the ROME criteria used for the diagnosis of irritable bowel syndrome (IBS), and as such many patients with underlying Celiac disease may be mistakenly diagnosed as having IBS. The aim of the present study was to determine the prevalence of Celiac disease in patients with IBS fulfilling ROME III criteria.

MATERIALS AND METHODS

Patients who fulfilled ROME III criteria for irritable bowel syndrome were screened for Celiac disease using the Biocard(TM) Celiac Disease Stick test, and patients who tested positive had their serum samples analyzed for antigliadin IgA and IgG, and anti-tissue transglutaminase IgA antibodies. Patients with detectable antibody levels underwent endoscopic duodenal biopsy to confirm a diagnosis of Celiac disease.

RESULTS

Two of 100 patients who were diagnosed as having irritable bowel syndrome as per the Roma III criteria were found to have elevated levels of serum antigliadin IgA and IgG, and anti-tissue transglutaminase IgA antibodies, with histological evidence of Celiac disease on examination of duodenal biopsy. Both patients were started on a gluten-free diet, showing significant improvement in their symptoms on follow-up.

CONCLUSIONS

Celiac disease is a common finding among patients labeled as IBS. Celiac disease must be considered in differential diagnosis of IBS especially in the therapy refractory group.

Irritable bowel syndrome: can nutrient manipulation help?

PURPOSE OF REVIEW

To describe the evidences for the usefulness of dietary manipulations (including the use of probiotics and prebiotics) in the management of irritable bowel syndrome (IBS).

RECENT FINDINGS

Exclusion diets do not have a role in the management of these patients except in the case of malabsorbed sugars (lactose, fructose). However, recent work suggests that excluding these sugars is more effective in non-IBS than in IBS patients. Also, the first small open series on the use of very low (20 g/day) carbohydrate diet (VLCD) in IBS has been published with promising results. However, safety concerns do not allow us to recommend them. In the period of review, further evidence has been provided on the role of psyllium in IBS. Also, the available evidence on the use of probiotics in IBS has been meta-analyzed.

SUMMARY

IBS patients should eat a balanced diet without restrictions, and (except for malabsorbed sugars) exclusion diets are not useful in most of them. The role of VLCD remains to be established. The concept that increasing fiber intake is useful for IBS may not be true for all patients, and hydrophilic colloids (e.g. psyllium) are preferred. There is growing evidence for the effectiveness of probiotics in IBS.

The economics of coeliac disease: a population-based study

BACKGROUND

Despite increasing prevalence, the economic implications of coeliac disease are just emerging.

AIMS

To assess the impact of coeliac disease diagnosis on healthcare costs and the incremental costs associated with coeliac disease.

METHODS

Administrative data for a population-based cohort of coeliac disease cases and matched controls from Olmsted County, Minnesota were used to compare (i) direct medical costs 1 year pre- and post-coeliac disease diagnosis for 133 index cases and (ii) 4-year cumulative direct medical costs incurred by 153 index cases vs. 153 controls. Analyses exclude diagnostic-related and out-patient pharmaceutical costs.

RESULTS

Average total costs were reduced by $1764 in the year following diagnosis (pre-diagnosis cost of $5023 vs. $3259; 95% CI of difference: $688 to $2993). Over a 4-year period, coeliac disease cases experienced higher out-patient costs (mean difference of $1457; P = 0.016) and higher total costs than controls (mean difference of $3964; P = 0.053). Excess average total costs were concentrated among males with coeliac disease ($14,191 vs. $4019 for male controls; 95% CI of difference: $2334 to $20,309).

CONCLUSIONS

Coeliac disease-associated costs indicate a significant economic burden of disease, particularly for diseased males. Diagnosis and treatment of coeliac disease reduce medical costs of care suggesting an economic advantage to earlier detection and treatment.

Irritable bowel syndrome: role of food in pathogenesis and management

Patients with the irritable bowel syndrome (IBS) commonly report the precipitation of symptoms on food ingestion. Though the role of dietary constituents in IBS has not been extensively studied, food could contribute to symptom onset or even the causation of IBS through a number of mechanisms. First, the physiological response of the intestine to food ingestion could precipitate symptoms in predisposed individuals; second, there is some evidence that allergy or intolerance to a particular food can produce IBS-like symptoms, third, certain foods may alter the composition of the luminal milieu, either directly or indirectly through effects on bacterial metabolism, and thus induce symptoms and, finally, IBS may develop following exposure to food-borne pathogens. Anticipatory, psychological factors generated by previous negative experiences with food ingestion or other factors may also contribute though their contribution has been scarcely quantified. Not surprisingly, there is considerable interest in the potential roles of diet and food supplements in the therapy of IBS; for the most part, the evidence base for such recommendations remains slim though certain probiotics show considerable promise.

Efficient diagnosis of suspected functional bowel disorders

Functional bowel disorders (FBDs) are common disorders that are characterized by various combinations of abdominal pain and/or discomfort, bloating and changes in bowel habits. At present, diagnosing FBDs often incurs considerable health-care costs, partly because unnecessary investigations are performed. Patients are currently diagnosed as having an FBD on the basis of a combination of typical symptoms, normal physical examination and the absence of alarm features indicative of an organic gastrointestinal disease. Basic laboratory investigations, such as a complete blood count, measurement of the erythrocyte sedimentation rate and serological tests for celiac disease, are useful in the initial evaluation. No further investigations are needed for most patients who have typical symptoms and no alarm symptoms. The most important alarm symptoms include signs of gastrointestinal bleeding, symptom onset above 50 years of age, a family history of colorectal cancer, documented weight loss and nocturnal symptoms. The presence of alarm symptoms obviously does not exclude an FBD, but further investigation is needed before confirmation of the diagnosis. For patients with predominant and severe diarrhea, a more thorough diagnostic work-up should normally be considered, including colonoscopy with colonic biopsies and a test for bile-acid malabsorption.

Detection of Celiac disease in primary care: a multicenter case-finding study in North America

BACKGROUND

Celiac disease (CD) is one of the most common lifelong disorders in western countries. However, most cases remain currently undiagnosed in North America, mostly due to poor awareness of CD by primary care physicians.

OBJECTIVES

The aims of this study were (a) to determine whether an active case-finding strategy in primary care could increase the frequency of CD diagnosis and (b) to determine the most common clinical presentations of the condition.

METHODS

This was a multicenter, prospective study involving adult subjects during the years 2002-2004, attending one of the participating practices. All individuals with symptoms or conditions known to be associated with CD were tested for immunoglobulin A anti-transglutaminase (tTG) antibodies, and those with elevated anti-tTG were subsequently tested for IgA antiendomysial antibodies (EMA). All subjects who were positive for EMA were advised to undergo an intestinal biopsy and HLA typing.

RESULTS

The study group included 737 women and 239 men, with a median age of 54.3 yr. A positive anti-tTG test was found in 30 out of 976 investigated subjects (3.07%, 95% CI 1.98-4.16). CD was diagnosed in 22 patients (18 women, 4 men). The most frequent reasons for CD screening in these 22 cases were bloating (12/22), thyroid disease (11/22), irritable bowel syndrome (7/22), unexplained chronic diarrhea (6/22), chronic fatigue (5/22), and constipation (4/22). The prevalence of CD in the serologically screened sample was 2.25% (95% CI 1.32-3.18). The diagnostic rate was low at baseline (0.27 cases per thousand visits, 95% CI 0.13-0.41) and significantly increased to 11.6 per thousand visits (95% CI 6.8-16.4, P < 0.001) following active screening implementation.

CONCLUSIONS

This study demonstrates that an active case-finding strategy in the primary care setting is an effective means to improve the diagnostic rate of CD in North America.

Predictors of clinical response to gluten-free diet in patients diagnosed with diarrhea-predominant irritable bowel syndrome

BACKGROUND & AIMS

Gluten sensitivity might cause abdominal symptoms in the absence of villous atrophy. We examined the prevalence of celiac disease-associated serum antibodies in diarrhea-dominant irritable bowel syndrome (d-IBS) patients and their efficacy in combination with HLA-DQ2 expression to predict the response to gluten-free diet.

METHODS

HLA-DQA1*0501/DQB1*0201 expression and celiac disease-associated IgA and IgG serum antibodies against gliadin and tissue-transglutaminase were measured in 145 patients with d-IBS, 74 patients with untreated and treated celiac disease, and 57 patients with active IBD. Follow-up antibody levels, stool frequency, and gastrointestinal symptom scores were determined in 41 d-IBS patients (26 women, 15 men; median age, 46 years, range, 30-67 years) who participated in a nonrandomized evaluation of 6 months of gluten-free diet.

RESULTS

Increased celiac disease-associated serum IgG, but not IgA, was found in the majority of patients with treated (55%) as in most patients with untreated celiac disease (97%). In d-IBS patients, celiac disease-associated serum IgG antibodies (37%) and HLA-DQ2 expression (39%) were more frequent than in IBD patients (18% and 23%, respectively). After 6 months of gluten-free diet, stool frequency and gastrointestinal symptom score returned to normal values in 60% of d-IBS patients who were positive and in 12% who were negative for HLA-DQ2 and celiac disease-associated serum IgG; both parameters combined yielded positive and negative predictive values of 56% (95% confidence interval, 30%-80%) and 88% (69%-97%), respectively.

CONCLUSIONS

Celiac disease-associated serum IgG and HLA-DQ2 expression can identify likely responders to gluten-free diet in d-IBS patients.

Does coeliac disease affect colorectal practice?

INTRODUCTION

Screening studies of healthy volunteers have determined that coeliac disease affects 1% of the adult European population. Despite this, the majority of cases are unrecognised. Coeliac disease often presents in adults with non-specific gastrointestinal symptoms. This may suggest that unrecognised cases are being seen in colorectal clinics with vague gastrointestinal symptoms, iron deficiency anaemia or irritable bowel syndrome. In addition, cases of coeliac disease may also be presenting as an emergency admission with non-specific abdominal pain.

OBJECTIVE

This review provides an update of the published data on case finding for coeliac disease, with the aim of improving the recognition of this disease in clinical practice.

Diagnosis of celiac disease in clinical practice: physician's alertness to the condition essential

GOALS

We have for several years been training health personnel to recognize celiac disease, and have advocated serologic screening in risk groups. The aim was to establish whether this approach would offer an alternative to population screening, which has yielded a prevalence of 1% in Finland.

BACKGROUND

The number of detected celiac disease cases is much lower than that obtained in serologic screening studies.

STUDY

Nationwide recommendations for the detection of celiac disease were published in 1998, and training of health personnel took place in 2001 to 2002. The prevalence of celiac disease was calculated from the national registry of patients receiving reimbursement for dietary costs, attested by physician's statement. In 1 of the 10 statements the diagnostic criteria and clinical manifestations were scrutinized.

RESULTS

The nationwide prevalence of celiac disease was 0.45%; 0.7% in the highest to 0.3% in the lowest area. The annual number of new patients increased from 5/100,000 in the early 1980s to 20/100,000 today. The percentage of patients found in risk groups (relatives of celiac disease patients, patients with extraintestinal symptoms or concomitant autoimmune disorders) was currently 16.3% in the high and 6.6% in the low prevalence area. Seventeen percent of patients had dermatitis herpetiformis, and its incidence was declining.

CONCLUSIONS

A maximal prevalence of 0.7% of celiac disease was ascertained; educating primary health care staff regarding the protean manifestations of the disease seemed to be the key issue. The increase in incidence implies that a prevalence of 1.0% is possible, rendering population screening unnecessary.

Screening for celiac disease in asymptomatic children with Down syndrome: cost-effectiveness of preventing lymphoma

BACKGROUND

Studies demonstrate an increased prevalence of celiac disease in persons with Down syndrome, leading some organizations and authors to recommend universal screening of children with Down syndrome. However, many children with Down syndrome are asymptomatic, and the long-term implications of screening are unknown. The complication of celiac disease that leads to mortality in the general population is non-Hodgkin's lymphomas.

OBJECTIVES

The purpose of this research in asymptomatic children with Down syndrome was to (1) calculate the number needed to screen to prevent a single case of lymphoma and (2) present a cost-effectiveness study of screening.

METHODS

We constructed a decision tree using probabilities derived from the published literature for Down syndrome or from the general population where Down syndrome-specific data were not available. Celiac disease was determined by serologic screening and confirmation with intestinal biopsy. Sensitivity analysis was used to alter probability estimates affecting the cost of preventing lymphoma.

RESULTS

Using our baseline values, the no-screen strategy is dominant; that is, screening not only costs more but also results in fewer quality-adjusted life-years. A screening strategy costs more than $500,000 per life-year gained. Screening all asymptomatic children with Down syndrome for celiac disease costs almost $5 million to prevent a single case of lymphoma.

CONCLUSION

These analyses do not support the cost-effectiveness of screening, and more data are needed before recommendations to screen asymptomatic children with Down syndrome for celiac disease can be made.

The role of food intolerance in irritable bowel syndrome

Irritable bowel syndrome patients frequently believe that food intolerances are to blame for many of their symptoms, although not uncommonly this is caused by the nonspecific increase in gut motility that occurs with food ingestion. Nevertheless, dietary manipulation may result in substantial improvement in IBS symptomatology provided it is individualized to the particular patient. By further understanding the mechanisms involved in dietary intolerance, it should be possible to optimize the benefits of this approach to treatment.

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.

Should adults be screened for celiac disease? What are the benefits and harms of screening?

The symptoms of celiac disease are diverse, and the disease is often asymptomatic. Without active serologic screening, most cases probably remain undiagnosed. Recent serologic screening assays allow mass screening for the disease. However, there is no evidence as yet to suggest that symptom-free celiac disease patients run an increased risk of small intestinal lymphoma or other complications. The prevention of osteoporosis seems to be the strongest indicator for widespread screening today. Screening asymptomatic individuals for celiac disease may be even harmful. A lifelong gluten-free diet is not easy to maintain, and the subject's quality of life may deteriorate. It is also debatable whether patients found by active screening adhere to a gluten-free diet similarly to symptomatic ones. The cost-effectiveness of population screening is dubious. Serologic screening should be applied in individuals with even subtle symptoms indicative of celiac disease, such as subclinical-isolated iron deficiency. In various autoimmune conditions, the risk of celiac disease is approximately 5% and, in individuals with affected first-degree relatives, 15%. Infertility, neurologic symptoms such as polyneuropathy, ataxia, epilepsy with posterior cerebral calcification, and osteoporosis are conditions in which celiac disease should be kept in mind. Elevated aminotransferases and liver failure can lead to a diagnosis of celiac disease. Evidence today does not support mass screening of celiac disease. Instead, increased alertness should be observed in patients at risk of the condition.

Advances in celiac disease

PURPOSE OF REVIEW

This article aims to summarize recent critical research in celiac disease.

RECENT FINDINGS

The crucial epitopes that confer toxicity to gliadin and related prolamins continue to be defined, as do methods of assessing their toxicity. New approaches to making the gluten-free diet more palatable are being studied.

SUMMARY

The position of proline residues is critical to the toxicity of cereal proteins to patients with celiac disease. Other genetic factors, apart from HLA status, remain elusive. Exciting advances in altering the toxicity of cereal proteins are being made.