Screening for unrecognized coeliac disease in subfertile couples

Phenome-wide Mendelian randomization analysis reveals multiple health comorbidities of coeliac disease

BACKGROUND

Coeliac disease (CeD) has been associated with a broad range of diseases in observational data; however, whether these associations are causal remains undetermined. We conducted a phenome-wide Mendelian randomization analysis (MR-PheWAS) to investigate the comorbidities of CeD.

METHODS

Single nucleotide polymorphisms (SNPs) associated with CeD at the genome-wide significance threshold and without linkage disequilibrium (R2 <0.001) were selected from a genome-wide association study including 12,041 CeD cases as the instrumental variables. We first constructed a polygenic risk score for CeD and estimated its associations with 1060 unique clinical outcomes in the UK Biobank study (N = 385,917). We then used two-sample MR analysis to replicate the identified associations using data from the FinnGen study (N = 377,277). We performed a secondary analysis using a genetic instrument without extended MHC gene SNPs.

FINDINGS

Genetic liability to CeD was associated with 68 clinical outcomes in the UK Biobank, and 38 of the associations were replicated in the FinnGen study. Genetic liability to CeD was associated with a higher risk of several autoimmune diseases (type 1 diabetes and its complications, Graves' disease, Sjögren syndrome, chronic hepatitis, systemic and cutaneous lupus erythematosus, and sarcoidosis), non-Hodgkin's lymphoma, and osteoporosis and a lower risk of prostate diseases. The associations for type 1 diabetes and non-Hodgkin's lymphoma attenuated when excluding SNPs in the MHC region, indicating shared genetic aetiology.

INTERPRETATION

This study uncovers multiple clinical outcomes associated with genetic liability to CeD, which suggests the necessity of comorbidity monitoring among this population.

FUNDING

This project was funded by Karolinska Institutet and the Swedish Research Council.

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.

The accuracy of diagnostic indicators for coeliac disease: A systematic review and meta-analysis

BACKGROUND

The prevalence of coeliac disease (CD) is around 1%, but diagnosis is challenged by varied presentation and non-specific symptoms and signs. This study aimed to identify diagnostic indicators that may help identify patients at a higher risk of CD in whom further testing is warranted.

METHODS

International guidance for systematic review methods were followed and the review was registered at PROSPERO (CRD42020170766). Six databases were searched until April 2021. Studies investigating diagnostic indicators, such as symptoms or risk conditions, in people with and without CD were eligible for inclusion. Risk of bias was assessed using the QUADAS-2 tool. Summary sensitivity, specificity, and positive predictive values were estimated for each diagnostic indicator by fitting bivariate random effects meta-analyses.

FINDINGS

191 studies reporting on 26 diagnostic indicators were included in the meta-analyses. We found large variation in diagnostic accuracy estimates between studies and most studies were at high risk of bias. We found strong evidence that people with dermatitis herpetiformis, migraine, family history of CD, HLA DQ2/8 risk genotype, anaemia, type 1 diabetes, osteoporosis, or chronic liver disease are more likely than the general population to have CD. Symptoms, psoriasis, epilepsy, inflammatory bowel disease, systemic lupus erythematosus, fractures, type 2 diabetes, and multiple sclerosis showed poor diagnostic ability. A sensitivity analysis revealed a 3-fold higher risk of CD in first-degree relatives of CD patients.

CONCLUSIONS

Targeted testing of individuals with dermatitis herpetiformis, migraine, family history of CD, HLA DQ2/8 risk genotype, anaemia, type 1 diabetes, osteoporosis, or chronic liver disease could improve case-finding for CD, therefore expediting appropriate treatment and reducing adverse consequences. Migraine and chronic liver disease are not yet included as a risk factor in all CD guidelines, but it may be appropriate for these to be added. Future research should establish the diagnostic value of combining indicators.

The prevalence of celiac disease in women with infertility-A systematic review with meta-analysis

PURPOSE

To determine the prevalence of celiac disease in infertile women.

METHODS

A systematic search of four databases was conducted up until February 6, 2020. The search terms "c(o)eliac disease", "gluten", "vill(o)us atrophy", "infertility" and "subfertility" yielded 1142 unique hits. Articles in other languages than English, conference abstracts, letters, and publications where relevant information was missing were excluded. In our main analysis, celiac disease had to be verified by duodenal biopsy. The titles and abstracts, and the full-text articles were independently reviewed by two researchers. A fixed-effect model was used to calculate the weighted prevalence.

RESULTS

Based on 11 studies (1617 women), the pooled prevalence of biopsy-confirmed celiac disease was 0.7% (95% CI = 0.2%-1.2%) in women with any infertility. Restricting our study population to women with unexplained infertility, the pooled prevalence of biopsy-confirmed celiac disease was 0.6% (95% CI = 0.0%-1.6%). When including studies where celiac disease had been defined per serology (20 studies; 5158 women), the pooled prevalence of celiac disease was 1.1% (95% CI = 0.6%-1.6%) in women with any infertility.

CONCLUSION

Our results indicate that celiac disease is not more common in infertile women than in the general population. Celiac screening in infertile women may have low yield.

Exploring undiagnosed celiac disease in women with recurrent reproductive failure: The gluten-free diet could improve reproductive outcomes

PROBLEM

Which is the prevalence and seroprevalence of celiac disease (CD) in women with recurrent reproductive failure?

METHOD OF STUDY

Retrospective study performed in a single infertility clinic from September 2016 to December 2017. A total of 690 women with unexplained history of recurrent miscarriage and/or recurrent implantation failure were consecutively recruited. IgA anti-transglutaminase 2 (TG2) antibody data were collected, as well as IgG anti-TG2 and IgA/IgG anti-deamidated gluten peptide (DGP) data in most cases, and IgG anti-gliadin antibodies occasionally. In selected women, HLA-DQ genotyping was requested. Biopsy was suggested to all women with positive serological results or belonging to CD risk groups. Reproductive outcomes were recorded from women with high suspicion of CD and a control group comprised of 49 women.

RESULTS

Anti-TG2-positive women comprised 1% of the sample. An additional 4% was observed considering less-specific antibodies (31 women). Only 39% of sero-positive women accepted duodenal biopsy. HLA and biopsy data discarded CD in 14 sero-positive cases (37%), only one with anti-TG2 antibodies. CD was suggested in 10 sero-positive and three sero-negative women (1.9%). Compared with controls, the live birthrate of the studied women with probable CD was significantly decreased before gluten removal of the diet (P = .015), but significantly increased after that (P = .020).

CONCLUSION

One percent CD prevalence should be expected after anti-TG2 serological screening. However, more sensitive approaches should be explored, especially considering the potential beneficial effect of the gluten-free diet on the reproductive outcomes of women with CD.

Systematic Review and Meta-Analysis of Prevalence of Coeliac Disease in Women with Infertility

We aimed to estimate the seroprevalence and the prevalence of coeliac disease (CD) in women with reproductive problems. A systematic review of English published articles until June 2019 was performed in PubMed and Scopus using the terms: (infertility and (coeliac disease OR gluten) OR (miscarriage and (coeliac disease OR gluten) OR (abortion and (coeliac disease OR gluten). All articles showing numerical data of anti-transglutaminase type 2 or anti-endomisium antibodies, or intestinal biopsy information were included. The study group comprised women with overall infertility, unexplained infertility, or recurrent spontaneous abortions. Two authors independently performed data extraction using a predefined data sheet. The initial search yielded 310 articles, and 23 were selected for data extraction. After meta-analysis, the pooled seroprevalence was very similar for overall and unexplained infertility, with a pooled proportion of around 1.3%–1.6%. This implies three times higher odds of having CD in infertility when compared to controls. The pooled prevalence could not be accurately calculated due to the small sample sizes. Further studies with increased sample sizes are necessary before giving specific recommendations for CD screening in women with reproductive problems, but current data seem to support a higher risk of CD in these women.

Coeliac disease and obstetric and gynaecological disorders: where are we now?

Coeliac disease (CD) is a chronic gluten-dependent enteropathy very common in the general population and characterized by an extremely heterogeneous clinical picture. Although its prevalence is growing worldwide, case-finding strategy remains the mainstay to diagnosis. Thus, correct identification of high-risk categories of patients who need to be tested for CD is an essential part of medical knowledge to a large number of specialists and primary care providers. In this regard, although CD might have a serious effect on women's reproductive health, a widespread consensus is lacking on which categories of obstetric and gynaecological disorders should be tested for CD. The aim of this review is to critically summarize the current literature relevant to CD and obstetric and gynaecological disorders and to provide practical proposals that may be helpful to clinicians involved in the management of these patients.

Endocrine complications of celiac disease: a case report and review of the literature

PURPOSE

The purpose of this article is to review recent literature regarding endocrine disorders related to celiac disease (CD).

METHODS

We describe a case report and review existing literature on the endocrine manifestations of CD.

RESULTS

CD is an autoimmune disorder characterized by intestinal inflammation in response to gluten. CD can cause a wide range of extra-intestinal complications, including endocrine manifestations. Metabolic bone disease including osteoporosis and osteopenia, vitamin D deficiency, secondary hyperparathyroidism and less frequently osteomalacia can be seen. In CD, fracture risk is increased by 30-40%, while risk for hip fracture is approximately doubled. The risk for other endocrine disorders, particularly autoimmune endocrinopathies, is also increased in those with CD compared to the general population. Epidemiologic data indicate the risk for hypothyroidism is 3-4 times higher among those with CD, while risk of type 1 diabetes is greater than double. Risk for primary adrenal insufficiency is a striking 11-fold higher in those with versus without CD, though the absolute risk is low. Fertility is reduced in women with CD before diagnosis by 37% while male fertility in the absence of hypogonadism does not appear to be affected. Other endocrine conditions including hyperthyroidism, ovarian failure, androgen insensitivity, impaired growth and growth hormone deficiency and autoimmune polyendocrine syndromes have also been associated with CD.

CONCLUSIONS

CD is associated with a wide range of endocrine manifestations.

Unrecognised coeliac disease among men and women undergoing fertility treatment: A screening study

BACKGROUND

Coeliac disease is an autoimmune disease triggered by dietary gluten and has been associated with several conditions influencing female and male reproduction. Due to unspecific symptoms, coeliac disease can be unrecognised for years.

OBJECTIVE

To estimate the prevalence of unrecognised coeliac disease among couples referred to fertility treatment.

METHODS

Cross-sectional screening for coeliac disease in men and women referred to fertility treatment using IgA tissue transglutaminase antibodies as a marker of coeliac disease and small-bowel biopsies to confirm the diagnosis. Participants answered a questionnaire on gluten intake, gastrointestinal symptoms and reproductive history.

RESULTS

A total of 893 participants (51% women) were screened and eight were coeliac disease antibody positive. Small-bowel biopsies were obtained from seven antibody positive participants and unrecognised coeliac disease was confirmed in one woman and three men, corresponding to a prevalence of 0.45% (95% confidence interval 0.12-1.14). The total prevalence, combining already diagnosed and unrecognised CD cases, was 0.63% (95% confidence interval 0.29-1.12).

CONCLUSION

The prevalence of unrecognised coeliac disease in a group of infertile patients was equivalent to that of the Danish general population and low compared with that observed in the majority of other screening studies of infertile patients. Surprisingly, it should be noted that more men than women had coeliac disease. This result does not support a need for routine screening among infertile patients.

Celiac Disease in Women With Infertility: A Meta-Analysis

BACKGROUND

Celiac disease (CeD) is a systemic disease with manifestations not limited to small intestine. The data on association between CeD and infertility is contradictory. There are no recommendations for the screening of female patients with infertility for CeD.

AIM

We conducted a meta-analysis to find out whether women with infertility are at higher risk of CeD.

METHODS

Literature search was performed using the MeSH keywords "CeD," "gluten," and "infertility." Diagnosis of CeD was based on positive serology and biopsies showing villous atrophy. Data were extracted about CeD patients in 3 groups-women with infertility (including unexplained infertility), unexplained infertility, and controls. Pooled odds ratio (OR) and prevalence, with 95% confidence intervals (CI), were calculated.

RESULTS

Of 105 relevant studies, 5 studies were included for calculation of pooled OR. Four additional studies, where data on controls were not available, were also considered for calculation of pooled prevalence of CeD. Women with infertility had 3.5 times higher odds of having CeD in comparison with control population (OR=3.5; 95% CI, 1.3-9; P<0.01). Similarly, women with "unexplained infertility" had 6 times higher odds of having CeD than controls (OR=6; 95% CI, 2.4-14.6). Of 884 women with infertility, 20 had CeD indicating a pooled prevalence of 2.3% (95% CI, 1.4-3.5). Of 623 women with "unexplained infertility," 20 had CeD. The pooled prevalence of CeD in women with unexplained infertility was 3.2 (95% CI, 2-4.9).

CONCLUSIONS

CeD is more prevalent in women with "all-cause" infertility and "unexplained" infertility than that in general population.

Screening for celiac disease in the general population and in high-risk groups

BACKGROUND

Celiac disease (CD) occurs in approximately 1% of the Western population. It is a lifelong disorder that is associated with impaired quality of life (QOL) and an excessive risk of comorbidity and death.

OBJECTIVES

To review the literature on screening for CD in relation to the current World Health Organization (WHO) criteria for mass screening.

METHODS

We performed a PubMed search to identify indexed papers on CD screening with a publication date from 1900 until 1 June 2014. When we deemed an abstract relevant, we read the corresponding paper in detail.

RESULTS

CD fulfills several WHO criteria for mass screening (high prevalence, available treatment and difficult clinical detection), but it has not yet been established that treatment of asymptomatic CD may reduce the excessive risk of severe complications, leading to higher QOL nor that it is cost-effective.

CONCLUSIONS

Current evidence is not sufficient to support mass screening for CD, but active case-finding may be appropriate, as we recognize that most patients with CD will still be missed by this strategy. Although proof of benefit is still lacking, screening for CD may be appropriate in high-risk groups.

Support for patients with celiac disease: A literature review

BACKGROUND

Celiac disease (CD) is a lifelong disorder. Patients are at increased risk of complications and comorbidity.

OBJECTIVES

We conducted a review of the literature on patient support and information in CD and aim to issue recommendations about patient information with regards to CD.

METHODS

DATA SOURCE

We searched PubMed for English-language articles published between 1900 and June 2014, containing terms related to costs, economics of CD, or education and CD.

STUDY SELECTION

Papers deemed relevant by any of the participating authors were included in the study.

DATA SYNTHESIS

No quantitative synthesis of data was performed. Instead we formulated a consensus view of the information that should be offered to all patients with CD.

RESULTS

There are few randomized clinical trials examining the effect of patient support in CD. Patients and their families receive information from many sources. It is important that health care personnel guide the patient through the plethora of facts and comments on the Internet. An understanding of CD is likely to improve dietary adherence. Patients should be educated about current knowledge about risk factors for CD, as well as the increased risk of complications. Patients should also be advised to avoid other health hazards, such as smoking. Many patients are eager to learn about future non-dietary treatments of CD. This review also comments on novel therapies but it is important to stress that no such treatment is available at present.

CONCLUSION

Based on mostly observational data, we suggest that patient support and information should be an integral part of the management of CD, and is likely to affect the outcome of CD.

Risk of infertility in patients with celiac disease: a meta-analysis of observational studies

CONTEXT

Celiac disease is an autoimmune disorder of the small intestine associated with several extra-intestinal features, such as reproductive disorders. The relationship between celiac disease and infertility has been previously assessed, with conflicting results.

OBJECTIVES

We seek to determine the relationship between celiac disease and infertility.

METHODS

Data was extracted from case-control or cohort design studies from 1966 to December 2013 using the MEDLINE-Pubmed, EMBASE, LILACS and Cochrane Library databases. We analyzed two kinds of trials: those assessing the risk of infertility in subjects with already diagnosed celiac disease, and those evaluating the prevalence of undiagnosed celiac disease in subjects with a diagnosis of infertility.

RESULTS

The search yielded 413 potentially relevant studies for revision, 12 of which were finally included for analysis. A significant association was found between women with a diagnosis of infertility and undiagnosed celiac disease [OR 3.09 (95% CI 1.74-5.49)]. When considering those studies assessing the occurrence of infertility in subjects with already-diagnosed celiac disease, no difference was found between celiac disease patients and control subjects [OR 0.99 (0.86-1.13)].

CONCLUSIONS

Undiagnosed celiac disease is a risk factor for infertility. Women seeking medical advice for this particular condition should be screened for celiac disease. Adoption of a gluten-free diet could have a positive impact on fertility in this group of patients.