Identification of coeliac disease in primary care

AGA Technical Review on the Evaluation of Functional Diarrhea and Diarrhea-Predominant Irritable Bowel Syndrome in Adults (IBS-D)

BACKGROUND & AIMS

The evaluation of patients with chronic watery diarrhea represents a diagnostic challenge for clinicians because organic causes, including inflammatory bowel disease, microscopic colitis, and chronic infection, must be differentiated from functional diarrhea and diarrhea-predominant irritable bowel syndrome. The purpose of this review is to summarize the available evidence on the usefulness of diagnostic tests in such patients.

METHODS

We searched MEDLINE and EMBASE via OVID, from 1978 until April 2017. We included diagnostic test accuracy studies reporting on the use of fecal and blood tests for the evaluation of adult patients with functional diarrhea, including irritable bowel syndrome. We assessed the risk of bias of included studies using a modified version of the Quality Assessment of Diagnostic Accuracy Studies II, and the certainty in the evidence using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. We calculated pooled sensitivity and specificity, and the proportion of patients with true and false positive and negative results. We evaluated the following tests: erythrocyte sedimentation rate, C-reactive protein, fecal lactoferrin, fecal calprotectin, serologic tests for celiac disease, tests for bile acid diarrhea, the commercially available version of anti-cytolethal distending toxin B and anti-vinculin antibodies, and tests for Giardia infection. We did not evaluate breath tests for small intestinal bacterial overgrowth, as they are not part of a standard diarrhea workup.

RESULTS

Thirty-eight studies proved eligible to evaluate 1 or more of these tests. Erythrocyte sedimentation rate and C-reactive protein were similar at discriminating organic from functional disease, with sensitivity and specificity, respectively, of 0.54-0.78 and 0.46-0.95 for erythrocyte sedimentation rate and 0.73 and 0.78 for C-reactive protein. Among fecal tests, fecal calprotectin in a range of 50-60 μg/g (pooled sensitivity 0.81; 95% confidence interval [CI], 0.75-0.86; pooled specificity 0.87; 95% CI, 0.78-0.92) and fecal lactoferrin in a range of 4.0-7.25 μg/g (pooled sensitivity 0.79; 95% CI, 0.73-0.84; pooled specificity 0.93; 95%CI 0.63-0.99) presented the lowest proportion of false-negative results (low certainty in the evidence). Among tests for celiac disease, IgA tissue transglutaminase presented the best diagnostic test accuracy (sensitivity range, 0.79-0.99; specificity range, 0.90-0.99) with moderate certainty in the evidence. Among tests for bile acid diarrhea, the ⁷⁵selenium homotaurocholic acid test performed better than serum fibroblast growth factor 19 and 7α-hydroxy-4-cholesten-3-one, but is not available in the United States. There was insufficient evidence to recommend serologic tests for irritable bowel syndrome at this time. There are several good diagnostic tests for Giardia infection.

CONCLUSIONS

Moderate to low certainty in the evidence indicates that available fecal and blood tests may play a role in the diagnostic workup of adult patients with functional diarrhea. At the moment, no tests are available to reliably rule in irritable bowel syndrome.

The association between socioeconomic status and the symptoms at diagnosis of celiac disease: a retrospective cohort study

BACKGROUND

There are little data on patient factors that impact diagnosis rates of celiac disease. This study aims to evaluate the association between patient socioeconomic status and the symptoms at diagnosis of celiac disease.

METHODS

A total of 872 patients with biopsy-proven celiac disease were categorized based on the presence or absence of (1) diarrhea and (2) any gastrointestinal symptoms at diagnosis. Univariate and multivariate analyses were used to assess the association between socioeconomic status and symptoms.

RESULTS

Patients without diarrhea at presentation had a higher mean per capita income (US$34,469 versus US$32,237, p = 0.02), and patients without any gastrointestinal symptoms had a higher mean per capita income (US$36,738 versus US$31,758, p < 0.01) compared with patients having such symptoms. On multivariable analysis adjusting for sex, age, autoimmune or psychiatric comorbidities, and income, per capita income remained a significant predictor of diagnosis without gastrointestinal symptoms (odds ratio: 1.71, 95% confidence interval: 1.17-2.50, p < 0.01), and it showed a trend towards significance in diagnosis without diarrhea (odds ratio: 1.40, 95% confidence interval: 0.98-2.02, p = 0.06).

CONCLUSIONS

Patients with nonclassical symptoms of celiac disease are less likely to be diagnosed if they are of lower socioeconomic status. Celiac disease may be under-recognized in this population due to socioeconomic factors that possibly include lower rates of health-seeking behavior and access to healthcare.

The characterization of the repertoire of wheat antigens and peptides involved in the humoral immune responses in patients with gluten sensitivity and Crohn's disease

Intestinal T cells from gluten sensitivity/celiac disease patients respond to a heterogeneous array of peptides. Our study extended this heterogeneity to humoral immune response to various wheat proteins and peptides in patients with gluten sensitivity or Crohn's disease. IgG and IgA antibodies in sera from those patients and healthy control subjects were measured against an array of wheat antigens and peptides. In gluten-sensitive patients, IgG reacted most against transglutaminase, prodynorphin, wheat extract, and α-, γ-, and ω-gliadin; IgA reacted most against wheat then transglutaminase, glutenin, and other peptides. In the sera of Crohn's disease patients, IgG reacted most against wheat and wheat germ agglutinin then transglutaminase, prodynorphin, α-, and γ-gliadin; IgA reacted foremost against prodynorphin then transglutaminase and α-gliadin. These results showed a substantial heterogeneity in the magnitude of IgG and IgA response against various wheat antigens and peptides. Measurements of IgG and IgA antibodies against such an array of wheat peptides and antigens can enhance the sensitivity and specificity of serological assays for gluten sensitivity and celiac disease and may also detect silent celiac disease or its overlap with inflammatory bowel disease.

Testing for gluten-related disorders in clinical practice: the role of serology in managing the spectrum of gluten sensitivity

Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the diagnosis of celiac disease. It is well known that immunoglobulin A tissue transglutaminase levels correlate with the degree of intestinal damage, and that values can fluctuate in patients over time. Serological testing can be used to identify symptomatic individuals that need a confirmatory biopsy, to screen at-risk populations or to monitor diet compliance in patients previously diagnosed with celiac disease. Thus, interpretation of serological testing requires consideration of the full clinical scenario. Antigliadin tests are no longer recommended for the diagnosis of classical celiac disease. However, our understanding of the pathogenesis and spectrum of gluten sensitivity has improved, and gluten-sensitive irritable bowel syndrome patients are increasingly being recognized. Studies are needed to determine the clinical utility of antigliadin serology in the diagnosis of gluten sensitivity.

Celiac disease: are endomysial antibody test results being used appropriately?

BACKGROUND

The aim of this study was to retrospectively examine how positive IgA-endomysial antibody (EMA) test results for celiac disease were being interpreted and acted on by physicians in the Calgary Health Region.

METHODS

We reviewed consecutive EMA test results, with or without a serum IgA, obtained during a 17-month period. Seropositive tests were cross-referenced to the surgical database to determine the number of patients who underwent intestinal biopsy and the results of the biopsy. We sent questionnaires to the ordering physicians of positive tests with no record of intestinal biopsy.

RESULTS

Among 11,716 EMA tests in 9533 patients, 349 results were positive in 313 patients (3%). Intestinal biopsies were performed in 218 (70%) of the seropositive patients; 194 of them were diagnostic of celiac disease. Celiac disease was also found in 10 EMA-negative patients. Of the 109 positive tests performed in 95 patients with no subsequent biopsy, 28 had appropriate indications to not perform a biopsy; the most common reason being that the test had been ordered to follow up on a previous biopsy-proven diagnosis of celiac disease (n = 21). For 33 other positive test results without a subsequent biopsy, management appeared to be inappropriate, most commonly (n = 21) because of a recommendation to follow a gluten-free diet despite lack of a tissue diagnosis of celiac disease. For the remaining 48 positive EMA results, administrative issues prevented evaluation (n = 19), the patients refused further evaluation (n = 11), or physician surveys were not returned (n = 18).

CONCLUSIONS

Celiac disease affected 2% of patients, with a similar prevalence in male and female patients. Most positive EMA tests (77%) were appropriately managed by physicians. Beginning a gluten-free diet without biopsy or failing to follow up on a positive EMA test remain common errors of management.

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.

Celiac disease in Tunisia: serological screening in healthy blood donors

BACKGROUND

Recent epidemiological studies in Europe and in USA using antigliadin antibodies and antiendomysium antibodies for initial screening have shown that the overall prevalence of celiac disease (CD) is about 1:200 (0.5%).

AIM

To screen for CD in healthy blood donors in Tunisia.

PATIENTS AND METHODS

Sera from 2500 healthy blood donors (median age: 21 years, 70% men and 30% women) were screened for IgG-antigliadin antibodies and IgA-antigliadin antibodies with an enzyme-linked immunosorbent assay. All sera with positive antigliadin antibodies were tested for antiendomysium antibodies using human umbilical cord cryosections as substrate.

RESULTS

Seven healthy blood donors (median age: 21 years; four men, three women) have antiendomysium antibodies. The prevalence of antiendomysium antibodies in healthy blood donors in Tunisia is 1:355 (0.28%).

CONCLUSIONS

On the basis of a high specificity of the antiendomysium antibodies, it is likely that the seven blood donors identified in this study have CD. These data suggest that CD is frequent in Tunisia.

Increasing numbers at a specialist coeliac clinic: contribution of serological testing in primary care

BACKGROUND

Serological testing, using IgA class endomysial and tissue transglutaminase antibodies has high sensitivity and specificity for coeliac disease and allows case finding by clinicians other than gastroenterologists. We reviewed new coeliac patients seen over a 9-year period to determine how the availability of serology, particularly to primary care physicians, has changed rates and sources of diagnosis.

METHODS

Files of patients attending a specialist coeliac clinic who were diagnosed from 1996 through 2004 were reviewed. Patients with villous atrophy consistent with gluten sensitive enteropathy (Marsh III) on duodenal biopsy were selected. Data analysed included clinical characteristics, endomysial and tissue transglutaminase antibodies status and source of request for serology.

RESULTS

Over the study period 347 new coeliac patients, comprising adults and children aged 10 years and over, were identified, of whom 163 (47%) were identified by serological testing in primary care, 152 (44%) at the hospital gastroenterology department and 32 (9%) by other physicians in secondary care. Over three consecutive 3-year periods, the percentage of patients identified in primary care rose from 28% through 47% to 60%, with a rise in total numbers diagnosed from 93 through 118 to 136. There was no change in patient clinical characteristics over the study period. Though tissue transglutaminase antibodies were less sensitive than endomysial antibodies, combined testing obtained a sensitivity of over 90%. Patients identified in primary care were significantly younger and more likely to present with diarrhoea as a primary symptom.

CONCLUSION

Currently over half of our coeliac patients are identified by serological testing in primary care, which has resulted in an overall rise in diagnosis rates. Primary care practitioners have an important role in the diagnosis of coeliac disease, particularly of patients who present with non-gastrointestinal symptoms. The contribution of specialists other than gastroenterologists in secondary care is disappointing and may improve with directed education.

Effect of a gluten-free diet on gastrointestinal symptoms in celiac disease

BACKGROUND

Atypical presentations of celiac disease appear to be at least as common as is the classic presentation of steatorrhea, diarrhea, and weight loss.

OBJECTIVE

We examined the effect of a gluten-free diet on gastrointestinal symptoms in a cohort of US patients with celiac disease.

DESIGN

A follow-up survey was conducted in 215 patients who were evaluated at the University of Iowa from 1990 through 1997 as having biopsy-confirmed celiac disease. The systematic survey asked detailed questions regarding gastrointestinal symptoms before and after the institution of a gluten-free diet in the patients, all of whom had been given the same dietary advice.

RESULTS

The group consisted of 160 female and 55 male patients. Although diarrhea was the most frequent symptom in untreated celiac disease, steatorrhea occurred in only one-fifth of patients. Other complaints were common, and most responded to gluten exclusion. The benefit of gluten exclusion was equally apparent in men and women. Diarrhea responded in most patients, usually within days, and the mean time to resolution was 4 wk. Many patients had alternating diarrhea and constipation, both of which were responsive to the gluten-free diet. Most patients had abdominal pain and bloating, which resolved with the diet.

CONCLUSIONS

Celiac disease causes a wide range of gastrointestinal symptoms. Clinicians must have a high level of suspicion to detect the atypical forms of celiac disease. With a gluten-free diet, patients have substantial and rapid improvement of symptoms, including symptoms other than the typical ones of diarrhea, steatorrhea, and weight loss.

Trends in the identification and clinical features of celiac disease in a North American community, 1950-2001

BACKGROUND AND AIMS

Celiac disease is considered rare in North America. However, an increasing incidence and widening clinical spectrum have been reported in many countries, and serologic screening suggests a higher prevalence of minimally symptomatic disease. This study reports temporal trends in the incidence of celiac disease in Olmsted County, Minnesota.

METHODS

All county residents diagnosed with celiac disease between 1950 and 2001 were identified through the Rochester Epidemiology Project. Incidence rates were calculated assuming a Poisson distribution, and changes in incidence by calendar year, age, and gender were assessed by using Poisson regression.

RESULTS

Altogether, 82 new cases of celiac disease were identified during the 50-year period. There was a marked female predominance (P < 0.005), and the incidence rates increased with age (P < 0.001) and calendar period (P < 0.001). The overall annual incidence of celiac disease was 2.1 per 100,000 (95% confidence interval [CI], 1.7-2.6) but increased from 0.9 per 100,000 (CI, 0.5-1.2) in 1950-1989 to 3.3 per 100,000 (95% CI, 2.2-4.4) in the 1990s. The incidence was 9.1 per 100,000 (95% CI, 5.2-13.0) in the final 2 years of the study. Serology prompted biopsy in a substantial proportion of recent diagnoses. Clinical features also changed over time, with less diarrhea and weight loss at presentation.

CONCLUSIONS

Celiac disease has increased recently in this well-characterized population. Milder clinical features and use of serology suggest an increased detection rate, although a true increase in incidence may have also occurred. Celiac disease is not rare in North America.

Antiendomysium antibodies in Brazilian patients with celiac disease and their first-degree relatives

BACKGROUND

Literature data have shown high specificity of antiendomysial antibodies (EmA IgA) in celiac disease. The scarcity of Brazilian reports concerning this subject motivated the present study.

OBJECTIVES

To determine the sensitivity and specificity of antiendomysial IgA antibodies in Brazilian celiac patients at diagnosis and after treatment, to confirm patient adherence to a gluten-free diet and to screen first-degree relatives.

METHODS

An extensive clinical and serological study was performed by investigating the presence of these antibodies in 392 individuals from Southern Brazil. Indirect immunofluorescence using human umbilical cord as substrate was employed and the total levels of IgA were determined by turbidimetry in all groups. The study was conducted on 57 celiac patients (18 at diagnosis, 24 who adhered to a gluten-free diet and 15 with marked or slight transgression of the diet), 115 relatives of celiac patients (39 families), 94 patients with other gastrointestinal diseases, and 126 healthy individuals from the general population.

RESULTS

The results demonstrated 100% positivity for the recently diagnosed patients and for those consuming gluten, in contrast to the patients who complied with the diet (0%). In the control group one individual was positive, but refused to undergo a biopsy. In the group of other gastrointestinal diseases, one positive patient presented ulcerative colitis, Down's syndrome and epilepsy, and the intestinal biopsy was diagnostic for celiac disease. These data showed 99.3% specificity for the test. Eighteen relatives were positive for antiendomysial antibodies IgA (15.65%), and comparison with the healthy population revealed a significant difference. An intestinal biopsy was obtained from seven subjects (one with total villous atrophy and six without alterations in the mucosal architecture, but all with a high number of intra-epithelial lymphocytes).

CONCLUSIONS

The method revealed 100% sensitivity and 99.3% specificity. Because it is not an invasive method it can be used for the screening of atypical and latent forms of celiac disease to avoid serial biopsies and to control adherence to a gluten-free diet with implications in the prevention of malignancy in celiac disease.