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

Cost-Effectiveness of Routine Monitoring of Long-Term Conditions in Primary Care: Informing Decision Modelling with a Systematic Review in Hypertension, Type 2 Diabetes and Chronic Kidney Disease

BACKGROUND

Long-term conditions (LTCs) are major public health problems with a considerable health-related and economic burden. Modelling is key in assessing costs and benefits of different disease management strategies, including routine monitoring, in the conditions of hypertension, type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) in primary care.

OBJECTIVE

This review aimed to identify published model-based cost-effectiveness studies of routine laboratory testing strategies in these LTCs to inform a model evaluating the cost effectiveness of testing strategies in the UK.

METHODS

We searched the Medline and Embase databases from inception to July 2023; the National Institute for Health and Care Institute (NICE) website was also searched. Studies were included if they were model-based economic evaluations, evaluated testing strategies, assessed regular testing, and considered adults aged >16 years. Studies identified were summarised by testing strategies, model type, structure, inputs, assessment of uncertainty, and conclusions drawn.

RESULTS

Five studies were included in the review, i.e. Markov (n = 3) and microsimulation (n = 2) models. Models were applied within T2DM (n = 2), hypertension (n = 1), T2DM/hypertension (n = 1) and CKD (n = 1). Comorbidity between all three LTCs was modelled to varying extents. All studies used a lifetime horizon, except for a 10-year horizon T2DM model, and all used quality-adjusted life-years as the effectiveness outcome, except a TD2M model that used glycaemic control. No studies explicitly provided a rationale for their selected modelling approach. UK models were available for diabetes and CKD, but these compared only a limited set of routine monitoring tests and frequencies.

CONCLUSIONS

There were few studies comparing routine testing strategies in the UK, indicating a need to develop a novel model in all three LTCs. Justification for the modelling technique of the identified studies was lacking. Markov and microsimulation models, with and without comorbidities, were used; however, the findings of this review can provide data sources and inform modelling approaches for evaluating the cost effectiveness of testing strategies in all three LTCs.

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.

Understanding the patient's experience of coeliac disease diagnosis: a qualitative interview study

BACKGROUND

Coeliac disease (CD) presents with non-specific symptoms, and delays to diagnosis are common. The traditional diagnostic pathway involves serological testing followed by endoscopic biopsy; however, the evidence is increasing about the effectiveness of a diagnosis without the need for a biopsy.

AIM

To understand the patient's experience of being diagnosed with CD.

DESIGN AND SETTING

A qualitative study was conducted, which involved semi-structured interviews with adults diagnosed with CD living in the UK.

METHOD

Participants (n = 20) were purposefully sampled from 200 adults who had completed a diagnostic confidence survey. Interviews were conducted via video-conferencing software (Zoom), recorded, and transcribed verbatim. Data were analysed using reflexive thematic analysis.

RESULTS

Interviewees faced pre-diagnostic uncertainty, presenting with non-specific symptoms that many experienced for several years and may have normalised. GPs often attributed their symptoms to alternative diagnoses, commonly, irritable bowel syndrome or anaemia. Investigations caused further uncertainty, with half of the interviewees unaware that their initial serology included a test for CD, and reporting long waits for endoscopy and challenges managing their diet around the procedure. Their uncertainty reduced once they received their biopsy results. Endoscopy was presented as the 'gold standard' for diagnosis and most interviewees believed that the procedure was necessary for diagnostic confidence and conviction in a lifelong gluten-free diet.

CONCLUSION

Patients experience uncertainty on the pathway to a diagnosis of CD. GPs could improve their experiences by being mindful of the possibility of CD and sharing information about serological testing. Policy and guidance should address the time to endoscopy and diet during diagnosis. If diagnosis without biopsy is adopted, then consideration should be given to clinical pathway implementation and communication approaches to reduce patient uncertainty.

Effect of gluten-free diet on autoimmune thyroiditis progression in patients with no symptoms or histology of celiac disease: a meta-analysis

Background

Hashimoto's thyroiditis (HT) is the most common autoimmune disease. HT may be associated with nonthyroidal autoimmune diseases, including celiac disease (CD) or other gluten-related conditions (GRC). In the last years, interest about gluten-free diet (GFD) has increased for its supposed extraintestinal anti-inflammatory effect; thus, many patients with HT initiate GFD on their own.

Objectives

The aim of this meta-analysis is to examine all available data in literature about the effect of a GFD on TgAb, TPOAb, TSH, FT4, and FT3 levels in patients with HT and no symptoms or histology of CD.

Methods

The study was conducted according to MOOSE (Meta-analysis Of Observational Studies in Epidemiology). The search was performed on databases PubMed and Scopus. The last search was performed on 7 February 2023. Quality assessment was performed. Meta-analyses were performed using the random-effect model. Hedges' g was used to measure the effect size (ES). Statistical analyses were performed using StataSE 17.

Results

The online search retrieved 409 articles, and 4 studies with a total of 87 patients were finally included for quantitative analysis. The risk of bias was generally low. The mean period of GFD was almost 6 months. The meta-analyses showed reduction in antibody levels with ES: -0.39 for TgAb (95% CI: -0.81 to +0.02; p = 0.06; I² = 46.98%) and -0.40 for TPOAb (95% CI: -0.82 to +0.03; p = 0.07; I² = 47.58%). TSH showed a reduction with ES: -0.35 (95% CI: -0.64 to -0.05; p = 0.02; I² = 0%) and FT4 showed an increase with ES: +0.35% (95% CI: 0.06 to 0.64; p = 0.02; I² = 0%). FT3 did not display variations (ES: 0.05; 95% CI: -0.38 to +0.48; p = 0.82; I² = 51%). The heterogeneity of TgAb, TPOAb, and FT3 data was solved performing sub-analyses between patients with or without GRC (TgAb p = 0.02; TPOAb p = 0.02; FT3 p = 0.04) and only for FT3, performing a sub-analysis between patients taking and not taking LT4 (p = 0.03).

Conclusion

This is the first meta-analysis investigating the effect of GFD on HT. Our results seem to indicate a positive effect of the gluten deprivation on thyroid function and its inflammation, particularly in patients with HT and GRC. However, current lines of evidence are not yet sufficient to recommend this dietary approach to all patients with a diagnosis of HT.

Coeliac Disease Case-Control Study: Has the Time Come to Explore beyond Patients at Risk?

The worldwide prevalence of asymptomatic coeliac disease (CD) is increasing, which is in part due to the routine screening of children with risk factors. Both symptomatic and asymptomatic patients with CD are at risk of long-term complications. The objective of this study was to compare the clinical characteristics of asymptomatic and symptomatic children at the time of CD diagnosis. A case-control study was conducted using data from a cohort of 4838 CD patients recruited from 73 centers across Spain between 2011 and 2017. A total of 468 asymptomatic patients (cases) were selected and matched by age and sex with 468 symptomatic patients (controls). Clinical data, including any reported symptoms, as well as serologic, genetic, and histopathologic data were collected. No significant differences were found between the two groups in most clinical variables, nor in the degree of intestinal lesion. However, the asymptomatic patients were taller (height z-score -0.12 (1.06) vs. -0.45 (1.19), p < 0.001) and were less likely to have anti transglutaminase IgA antibodies ≥ 10 times the upper normal limit (66.2% vs. 758.4%, p = 0.002). Among the 37.1% of asymptomatic patients who were not screened for CD due to the absence of risk factors, only 34% were truly asymptomatic, while the remaining 66% reported non-specific CD-related symptoms. Therefore, expanding CD screening to any child who undergoes a blood test could reduce the burden of care for some children, as many of those considered asymptomatic reported non-specific CD-related symptoms.