Case-finding in primary care for coeliac disease: Accuracy and cost-effectiveness of a rapid point-of-care test

Rapid Anti-tTG-IgA Screening Test for Early Diagnosis of Celiac Disease in Pediatric Populations

A large number of patients with celiac disease (CD) remain undiagnosed because they do not fulfill the criteria for entry into the conventional diagnostic workflow. This study evaluated the clinical utility of anti-tissue transglutaminase IgA antibody lateral flow immunoassays (anti-tTG-IgA LFIA) in the undiagnosed-CD-based pediatric population and the impact of a gluten-free diet (GFD) on screening-detected CD. A total of 576 volunteers were tested for anti-tTG-IgA. Gluten consumption habits, CD related symptoms, and risk factors for CD development were evaluated. Volunteers testing positive for anti-tTG-IgA were referred to the conventional CD diagnostic workflow, and the impact of the GFD on health-related quality of life (HR-QoL) was measured. Among them, 13 had a positive anti-tTG-IgA LFIA test result: 11 had confirmed CD (1.91%), one refused confirmatory tests, and another is undergoing diagnosis. Regarding the CD prevalence, no significant differences were observed among risk (1.89%) and symptomatic (2.65%) groups and the entire tested population (1.55%). Rapid anti-tTG-IgA LFIAs could be of clinical utility in primary care for the early identification of children with CD unidentified by the conventional diagnostic workflow. It could potentially reduce the costs of undiagnosed CD, avoiding unnecessary referrals to gastroenterologists, reducing diagnosis delays and long-term problems, and improving patients' HR-QoL.

2021 Patient Preferences for Point of Care Testing Survey: More Acceptance and Less Concern

BACKGROUND

The evolving opinions of our community members provide insights into how end-users perceive the value and identify key point-of-care test (POCT) characteristics.

METHODS

We deployed our validated 45-item English-language survey to uncompensated volunteers and compared the results from 1264 respondents in 2021 with those obtained in 2020.

RESULTS

Average responses for items regarding the benefits of POCTs demonstrated that the 2021 respondents indicated agreement with all 14 potential benefits. Average responses for items regarding concerns were distinctly different from those for benefits. The only concern item that scored in the agree range was "not having insurance coverage for POCTs." Average responses to the other 13 concern items were in the disagree range. For 8 of these items, the magnitude of disagreement was greater in the 2021 survey than was observed for the 2020 survey. Differences in POCT exposure over time and by US regions suggest that higher levels of exposure to POCTs in the East are associated with stronger public support.

CONCLUSIONS

Community members strongly support the development of accurate, convenient, easy-to-use, affordable, equitably available, in-home POCTs that produce immediate results. This empowers patients and home caregivers to diagnose, manage, enhance their adherence to medical treatments, and more efficiently engage their physicians.

Review article: Diagnosis of coeliac disease: a perspective on current and future approaches

Diagnostics will play a central role in addressing the ongoing dramatic rise in global prevalence of coeliac disease, and in deploying new non-dietary therapeutics. Clearer understanding of the immunopathogenesis of coeliac disease and the utility of serology has led to partial acceptance of non-biopsy diagnosis in selected cases. Non-biopsy diagnosis may expand further because research methods for measuring gluten-specific CD4+ T cells and the acute recall response to gluten ingestion in patients is now relatively straightforward. This perspective on diagnosis in the context of the immunopathogenesis of coeliac disease sets out to highlight current consensus, limitations of current practices, gluten food challenge for diagnosis and the potential for diagnostics that measure the underlying cause for coeliac disease, gluten-specific immunity.

Patient Preferences for Point-of-Care Testing: Survey Validation and Results

Background

Studies of current opinion of our community members for the characteristics, mode, and location of use, use cases, and overall enthusiasm for point-of-care testing (POCT) diagnosis and management tools are needed.

Study Design and Methods

Qualitative research methods were used to develop, refine, and evaluate hardcopy and electronic versions of a 45-item English language survey. The accuracy of the instrument was measured by recorded structured interview, and its precision was measured by comparison to its administration to a group of uncompensated volunteers.

Main Findings and Results

Comparison of survey and structured interview data demonstrated high levels of accuracy. Highly concordant with significant levels of correlation and of direct association indicated favorable precision. Ninety-three percent of respondents believed that POCT could improve their care, and 56% identified having a POCT in their home as a top priority. Accuracy, insurance coverage, immediacy of results, and ease of use were identified as the most important characteristics of a POCT.

Conclusions

Community members strongly support the development of accurate, in-home devices that produce immediate results that can be used to diagnose, manage, and encourage their adherence to treatments for their medical conditions.

Health Economic Evidence of Point-of-Care Testing: A Systematic Review

OBJECTIVE

Point-of-care testing (POCT) has become an essential diagnostic technology for optimal patient care. Its implementation, however, still falls behind. This paper reviews the available evidence on the health economic impact of introducing POCT to assess if poor POCT uptake may be related to lacking evidence.

STUDY DESIGN

The Scopus and PubMed databases were searched to identify publications describing a health economic evaluation of a point-of-care (POC) test. Data were extracted from the included publications, including general and methodological characteristics as well as the study results summarized in either cost, effects or an incremental cost-effectiveness ratio. Results were sorted into six groups according to the POC test's purpose (diagnosis, screening or monitoring) and care setting (primary care or secondary care). The reporting quality of the publications was determined using the CHEERS checklist.

RESULTS

The initial search resulted in 396 publications, of which 44 met the inclusion criteria. Most of the evaluations were performed in a primary care setting (n = 31; 70.5%) compared with a secondary care setting (n = 13; 29.5%). About two thirds of the evaluations were on POC tests implemented with a diagnostic purpose (n = 28; 63.6%). More than 75% of evaluations concluded that POCT is recommended for implementation, although in some cases only under specific circumstances and conditions. Compliance with the CHEERS checklist items ranged from 20.8% to 100%, with an average reporting quality of 72.0%.

CONCLUSION

There were very few evaluations in this review that advised against the implementation of POCT. However, the uptake of POCT in many countries remains low. Even though the evaluations included in this review did not always include the full long-term benefits of POCT, it is clear that health economic evidence across a few dimensions of value already indicate the benefits of POCT. This suggests that the lack of evidence on POCT is not the primary barrier to its implementation and that the low uptake of these tests in clinical practice is due to (a combination of) other barriers. In this context, aspects around organization of care, support of clinicians and quality management may be crucial in the widespread implementation of POCT.

A compact SPR biosensor device for the rapid and efficient monitoring of gluten-free diet directly in human urine

Celiac disease (CD) is a chronic autoimmune disorder induced in genetically susceptible individuals by the ingestion of gluten from wheat, rye, barley, or certain varieties of oats. A careful diet follow-up is necessary to avoid health complications associated with long-term gluten intake by the celiac patients. Small peptides (GIP, gluten immunogenic peptides) derived from gluten digestion, which are excreted in the urine and feces, have emerged as promising biomarkers to monitor gluten intake. We have implemented a simple and sensitive label-free point-of-care (POC) device based on surface plasmon resonance for the direct detection of these biomarkers in urine. The assay employs specific monoclonal antibodies and has been optimized for the detection of the 33-mer α2-gliadin, known as the main immunogenic peptide of wheat gluten, and for the detection of GIP. Direct detection in undiluted urine has been accomplished by using biosensing chips containing a robust and stable biorecognition layer, obtained after carefully optimizing the biofunctionalization protocol. Excellent limits of detection have been reached (1.6-4.0 ng mL^-1 using mAb G12 and A1, respectively), which ensures the detection of gluten peptides even when the gluten intake is around the maximum tolerable amount in the digestive tract (< 50 mg) for celiac individuals. No sample pretreatment, extraction, or dilution is required, and the analysis takes less than 15 min. The assays have excellent reproducibility' as demonstrated by measuring spiked urine samples containing the same target concentration using different biofunctionalized chips prepared and stored at different periods of time (i.e., CV% of 3.58% and 11.30%, for G12- and A1-based assays, respectively). The assay has been validated with real samples. These features pave the way towards an end-user easy-to-handle biosensor device for the rapid monitoring of gluten-free diet (GFD) and follow-up of the health status in celiac patients.

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.

Determining whether coeliac disease case-finding in primary care is better than random testing: a retrospective study

Background

Over 75% of patients (approximately half a million) with coeliac disease in the UK have not been formally diagnosed.

Aim

To determine if case-finding of coeliac disease is better than random testing in primary care.

Design & setting

A pragmatic study looked at all referrals across a 12-month period (December 2013–November 2014) for coeliac serology testing and the indications for testing across 38 GP practices in a well-defined geographical area in North Yorkshire. There was further follow-up for an additional 12 months to determine conversion of positive serology to duodenal biopsy.

Method

All serology samples sent into York Hospital biochemistry department during the study period were analysed for the indication for testing. Positive results were cross-referenced for duodenal biopsies over the following 12 months on the York Hospital pathology database.

Results

Case-finding of coeliac patients in primary care is no better than random testing of the population. Only 71% of patients with positive serology went on to have a duodenal biopsy in the following 12 months.

Conclusion

More education of the population and of primary care physicians is needed around the indications for checking for coeliac disease. It may be that primary care is not the best place to case-find patients with coeliac disease.

Diagnostic Accuracy of a Point-of-Care Test for Celiac Disease Antibody Screening among Infertile Patients

BACKGROUND

Screening for celiac disease among infertile patients has been suggested. Several rapid point-of-care (POC) tests aimed at detecting celiac disease antibodies have been developed. It has been suggested that these POC tests can be implemented as a replacement for standard laboratory tests.

OBJECTIVE

To evaluate the diagnostic accuracy of a POC test (Simtomax®) that detects celiac disease antibodies compared with standard laboratory tests when screening for celiac disease among patients referred for fertility treatment in 2 Danish fertility clinics.

METHODS

Serum samples were analyzed for IgA anti-tissue transglutaminase (TGA) as the reference standard test with a cutoff of ≥7 kU/L and by the index POC test based on IgA and IgG antibodies against deamidated gliadin peptides (DGP). In IgA deficiency, the reference standard test was IgG DGP with a cutoff of ≥7 kU/L. Participants answered a questionnaire on gluten intake, symptoms, and risk factors. Diagnostic confirmation was made by duodenal biopsies. IgA TGA/IgG DGP were used as the reference standard to calculate positive and negative predictive values.

RESULTS

A total of 622 men and women (51.6%) were enrolled during 2015. The reference standard IgA TGA/IgG DGP was positive in 7 participants (1.1% [95% CI 0.5-2.3]) and the POC test was positive in 84 participants (13.5% [95% CI 10.9-16.4]), 3 of whom also had positive reference standard tests. This yields a sensitivity of the index POC test of 42.9% (95% CI 9.9-81.6) and a specificity of 86.8% (95% CI 83.9-89.4). Positive and negative predictive values were 3.57% (95% CI 0.7-10.1) and 99.3% (95% CI 98.1-99.8).

CONCLUSION

The sensitivity of the POC test was low; however, the specificity was moderately good. The POC test had a high negative predictive value in this low prevalent population but missed 1 patient with biopsy-confirmed celiac disease. However, because of many false-positive tests, it cannot be recommended as replacement for standard laboratory tests but rather as a triage test to decide if the standard serology tests should be performed.

Serologic Diagnosis of Celiac Disease: New Biomarkers

Most patients affected by celiac disease (CD) are asymptomatic or hyposymptomatic and undiagnosed, and are at risk of preventable complications. Therefore, early diagnosis is highly recommended. Multiple diagnostic antibodies are available; the most frequently used is IgA to tissue transglutaminase (IgA-tTg). It may yield false results and, alone, does not address IgA deficiency. Recently, a new generation of anti-neo-epitope tTg check (IgG + IgA) has become available. It is highly sensitive and specific, covers IgA-deficient patients with CD, reflects intestinal damage, and has predictive potential in the diagnosis of CD.

Systematic Literature Review of the Economic Burden of Celiac Disease

BACKGROUND

The prevalence of celiac disease (CD) has rapidly increased over recent decades, but costs related to CD remain poorly quantified.

OBJECTIVE

This systematic review assessed the economic burden of CD in North America and Europe.

METHODS

MEDLINE, EMBASE, EconLit, and the Cochrane Library databases were systematically searched to identify English-language literature from 2007 to 2018 that assessed costs, cost effectiveness, and health resource utilization for CD.

RESULTS

Forty-nine studies met the inclusion criteria, of which 28 (57.1%) addressed costs of testing and diagnosis; 33 (67.3%) were from Europe. The cost per positive CD diagnosis of testing patients already undergoing esophagogastroduodenoscopy for other indications ranged from 1300 Canadian dollars ($Can) in Canada (2016 value) to €44,712 in the Netherlands (2013 value). Adding the CD test was cost effective when it combined diagnostic modalities (e.g., serology and biopsy). Direct annual excess costs to a US payer per diagnosed CD patient totaled $US6000 (2013 value) more than for a person without CD, chiefly due to outpatient care. Hospitalizations, emergency visits, and medication use were more common with CD. After initiating a gluten-free diet (GFD), patients visited primary care providers less often, used more medications, and missed fewer days from school and work.

CONCLUSIONS

Most of the few available economic studies of CD assess testing and diagnosis costs, especially in Europe. Methods of testing generally are considered cost effective when they combine diagnostic modalities in symptomatic patients. Most costs to a payer of managing CD derive from outpatient care. Following GFD initiation, patients lose fewer days from work and school than pretreatment.