Rapid anti-transglutaminase assay and patient interview for monitoring dietary compliance in celiac disease

The role of gluten challenge in the diagnosis of celiac disease: a review

INTRODUCTION

Duodenal biopsy is the gold standard in the diagnosis of celiac disease, with increasing utilization of serology. A gluten challenge may be required, for example, when dietary gluten reduction precedes appropriate diagnostic evaluations. Evidence on the best challenge protocol is currently sparse. Pharmaceutical trials in recent years may have provided new insights into the challenge and advanced the development of novel sensitive histological and immunological methods.

AREAS COVERED

This review outlines the current perspectives on the use of gluten challenge in the diagnosis of celiac disease and explores future directions in this area.

EXPERT OPINION

Comprehensive elimination of celiac disease before dietary gluten restriction is essential to avoid diagnostic uncertainties. Gluten challenge continues to have an important role in certain clinical scenarios, although it is important to understand its limitations in the diagnostic evaluation. The evidence so far permits no unequivocal recommendation considering the timing, duration, and amount of gluten used in the challenge. Thus, these decisions should be made on a case-by-case basis. Further studies with more standardized protocols and outcome measures are called for. In the future novel immunological methods may help to shorten or even avoid gluten challenge.

Challenges of Monitoring the Gluten-Free Diet Adherence in the Management and Follow-Up of Patients with Celiac Disease

Celiac disease (CD) is a chronic gluten-responsive immune mediated enteropathy and is treated with a gluten-free diet (GFD). However, a strict diet for life is not easy due to the ubiquitous nature of gluten. This review aims at examining available evidence on the degree of adherence to a GFD, the methods to assess it, and the barriers to its implementation. The methods for monitoring the adherence to a GFD are comprised of a dietary questionnaire, celiac serology, or clinical symptoms; however, none of these methods generate either a direct or an accurate measure of dietary adherence. A promising advancement is the development of tests that measure gluten immunogenic peptides in stools and urine. Causes of adherence/non-adherence to a GFD are numerous and multifactorial. Inadvertent dietary non-adherence is more frequent than intentional non-adherence. Cross-contamination of gluten-free products with gluten is a major cause of inadvertent non-adherence, while the limited availability, high costs, and poor quality of certified gluten-free products are responsible for intentionally breaking a GFD. Therefore, several studies in the last decade have indicated that many patients with CD who follow a GFD still have difficulty controlling their diet and, therefore, regularly consume enough gluten to trigger symptoms and damage the small intestine.

Adherence to Gluten-free Diet in a Celiac Pediatric Population Referred to the General Pediatrician After Remission

OBJECTIVES

Assessment of adherence to gluten-free diet in celiac disease (CD) is generally recommended. Few data are available about consequences of transition from the referral center to the general pediatrician (GP) once remission is achieved.

METHODS

Adherence was assessed in patients referred to the GP for an annual basis follow-up, called back for re-evaluation. Immunoglobulin A (IgA) antitissue transglutaminase (anti-tTG) antibodies and the Biagi score (BS) were determined at last follow-up at the referral center (V1), and at re-evaluation (V2). Patients were classified as adherent (BS 3-4, IgA anti-tTG <7 U/mL) and nonadherent (BS 0-2, IgA anti-tTG ≥7). Scores of adherence were correlated with personal and clinical data.

RESULTS

We evaluated 200 patients. Overall, we found good adherence rates in 94.95% of patients at V1 and 83.5% at V2. IgA anti-tTG were negative in 100% at V1 and 96.97% at V2. BS is 3 to 4 in 94.5% at V1 and 84% at V2. Adherence at V2 was significantly worse than V1 (P < 0.001). No significant associations were found between scores of adherence and sex, symptoms and age at diagnosis, family history of CD, comorbidity, and diagnosis by endoscopy. Age 13 years or older represents a risk factor for lack of compliance at V1 (P = 0.02) and V2 (P = 0.04), and foreign nationality at V2 (P = 0.001).

CONCLUSIONS

The BS, serology, and a clinical interview, integrated, are reliable tools for assessing pediatric adherence to gluten-free diet. We argue that referring patients to the GP after remission of CD is important, but the process must be improved and recommendations are required.

Diagnostic Accuracy of Point of Care Tests for Diagnosing Celiac Disease: A Systematic Review and Meta-Analysis

GOALS

To perform a systematic review and meta-analysis to estimate the overall diagnostic accuracy of point of care tests (POCTs) for diagnosing celiac disease (CD).

BACKGROUND

Recently, POCTs for CD have been developed and are commercially available. Studies have reported significant variability in their sensitivity (70% to 100%) and specificity (85% to 100%).

STUDY

We searched MEDLINE, EMBASE databases, and the Cochrane library through June 2017. Positive reference test was defined as villous atrophy along with positive celiac-specific serology and/or clinical improvement after gluten-free diet. Normal duodenal biopsy was defined as negative reference test. Bivariate random-effect model was used to present the summary estimates of sensitivities and specificities along with 95% confidence regions We assessed methodologic quality using the quality assessment of diagnostic accuracy studies-2 tool.

RESULTS

The pooled sensitivity and specificity of all POCTs (based on tTG or DGP or tTG+Anti-gliadin antibodies) for diagnosing CD were 94.0% [95% confidence interval (CI), 89.9-96.5] and 94.4% (95% CI, 90.9-96.5), respectively. The pooled positive and negative likelihood ratios for POCTs were 16.7 and 0.06, respectively. The pooled sensitivity and specificity for IgA-tTG-based POCTs were 90.5% (95% CI, 82.3-95.1) and 94.8% (95% CI, 92.5-96.4), respectively.

CONCLUSIONS

The pooled sensitivity and specificity of POCTs in diagnosing CD are high. POCTs may be used to screen for CD, especially in areas with limited access to laboratory-based testing. Further research assessing the diagnostic accuracy of individual POCTs and comparing it with other available POCTs is needed.

E-Healthcare for Celiac Disease-A Multicenter Randomized Controlled Trial

OBJECTIVE

To evaluate the (cost-)effectiveness of online consultations in follow-up of patients with celiac disease (CD).

STUDY DESIGN

Multicenter randomized, controlled trial involving 304 patients aged ≤25 years with CD for ≥1 year, randomized to an online (n = 156) or outpatient consultation (n = 148). An online consultation included questionnaires for symptom and growth measurement. Antitransglutaminase-type-2 antibodies were determined using a point-of-care (POC) test. Controls had a traditional consultation with antitransglutaminase-type-2 antibodies testing in laboratories. Both groups completed questionnaires concerning CD-specific health-related quality of life (HRQOL), gluten-free diet adherence, and patient satisfaction. Six months later, participants repeated HRQOL and patient satisfaction questionnaires and the POC test. The primary outcome was anti-transglutaminase-type-2 antibodies after 6 months, and the secondary outcomes were health problems, dietary adherence, HRQOL, patient satisfaction, and costs.

RESULTS

The performance of the POC test was inferior to laboratory testing (2/156 positive POC tests vs 13/148 positive laboratory tests; P = .003). Health problems were detected significantly more frequently using online consultation. The detection of growth problems and dietary transgressions was similar. HRQOL (from 1 [good] to 5 [poor]) improved after online consultation (from 3.25 to 3.16 [P = .013] vs controls from 3.10 to 3.23; P = .810). Patient satisfaction (from 1 [low] to 10 [high]) was 7.6 (online) vs 8.0 (controls; P = .001); 58% wished to continue online consultations. Mean costs per participant during the studied period were €202 less for the online group (P < .001).

CONCLUSIONS

The primary outcome could not be tested because the POC test was unreliable. Nevertheless, our results indicate that online consultations for children and young adults with CD are cost saving, increase CD-specific HRQOL, and are satisfactory for the majority.

TRIAL REGISTRATION

Trialregister.nl: NTR3688.

Point-of-care testing for celiac disease has a low sensitivity in endoscopy

BACKGROUND

Celiac disease (CD) is a common but underdiagnosed condition. A rapid point-of-care test (POCT) could reduce lead times and missed diagnoses.

OBJECTIVE

To assess the utility of an immunoglobulin (Ig) A tissue transglutaminase (TTG) antibody POCT in an endoscopic setting.

DESIGN

Prospective observational study.

SETTING

A single UK university hospital.

PATIENTS

Patients presenting with suspected CD, known CD, and routine endoscopy for upper GI symptoms.

INTERVENTIONS

All patients were tested with POCT, serum TTG, endomysial antibody (EMA), and upper GI endoscopy with duodenal biopsies at the same visit.

MAIN OUTCOME MEASUREMENTS

Comparison was made with histology in all cases, with villous atrophy regarded as diagnostic of CD.

RESULTS

A total of 576 patients (63.5% female, mean [± standard deviation] age 49.7 years [± 17.6 years]) were recruited. A total of 523 patients had no prior diagnosis of CD, and 53 patients had known CD coming for reassessment. A total of 117 patients were newly diagnosed with CD, and 82 were positively identified by the POCT. Sensitivity, specificity, positive predictive value, and negative predictive value were 70.1%, 96.6%, 85.4%, and 91.8%, respectively. In comparison, TTG and EMA both performed significantly better than the POCT. Sensitivity and specificity of TTG were 91.0% and 83.5%, respectively, and EMA were 83.8% and 97.5%, respectively. Of patients with known CD coming for reassessment, 26 had villous atrophy, and POCT results were positive in 16 (61.5%). There was poor agreement between POCT and standard serology.

LIMITATIONS

High pre-test probability of CD.

CONCLUSION

The performance of this POCT was disappointing compared with standard serology and cannot at present be recommended within the context of an endoscopy unit.

US perspective on gluten-related diseases

The incidence of allergy and autoimmune disease in the US and other industrialized nations is increasing, and gluten-related disorders are no exception. The US has documented a profound rise in celiac disease that cannot be fully explained by improved serological techniques or better recognition by physicians. Non-celiac gluten sensitivity, a condition only recently recognized by the medical community, has become a commonly diagnosed entity. Proteins, including gluten are increasingly being identified as a source of wheat allergy. Although the gluten free diet represents a safe and effective treatment for these conditions, there is still much to be learned about the development of gluten-related disorders and the apparent increase in incidence within the US. In this article, we present a review of current knowledge on the epidemiology of gluten-related disorders within a global context, with a focus on diagnostic trends and the evaluation of potential risk factors.

Simtomax, a novel point of care test for coeliac disease

INTRODUCTION

Coeliac disease is an autoimmune condition resulting from an abnormal reaction to dietary gluten leading to small bowel villous atrophy. International prevalence studies suggest that coeliac disease affects 1% of the adult population. However, despite its high prevalence, large numbers of patients go undiagnosed. One method of increasing detection rates would be to introduce a quick screening test in the form of a finger-prick blood test.

AREAS COVERED

There are currently four available point-of-care tests (POCTs) available for use by health professionals. This diagnostic evaluation will review the evidence for the use of POCTs in coeliac disease including Simtomax a novel test for deamidated gliadin peptides and total IgA level.

EXPERT OPINION

An accurate POCT has the potential to increase the rates of diagnosis of coeliac disease if used effectively as part of a case finding approach in primary or secondary care. Evidence for the use of Simtomax is currently fairly limited only drawing comparison with laboratory serology rather than the gold standard of histology and it has only been trialled in high-risk populations. However, results to date are encouraging and further research into this area is required.