Introduction

Current international guidelines recommend duodenal biopsies to confirm the diagnosis of coeliac disease in adult patients. However, growing evidence suggests that IgA anti-tissue transglutaminase (tTg) antibody levels ≥10 times the upper limit of normal (ULN) can accurately predict coeliac disease, eliminating the need for biopsy. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of the no-biopsy approach for the diagnosis of coeliac disease in adults.

Aims & Methods

We systematically searched MEDLINE, EMBASE, Cochrane Library and Web of Science from January 1998 to April 2023 for studies reporting the sensitivity and specificity of IgA-tTG ≥10×ULN against duodenal biopsies (Marsh grade ≥2) in adults with suspected coeliac disease. We used a bivariate random-effects model to calculate the summary estimates of sensitivity, specificity, positive and negative likelihood ratios. The positive and negative likelihood ratios were used to calculate the positive predictive value (PPV) of the no-biopsy approach across different pre-test probabilities of coeliac disease. This study was registered with PROSPERO, number CRD42023398812.

Results

Thirteen studies comprising 10,078 participants from 11 countries were included. The pooled prevalence of biopsy-proven coeliac disease in the included studies was 60% (95% CI, 36% - 84%). The summary sensitivity of IgA-tTG ≥10×ULN was 52% (95% CI, 41% - 62%), and the summary specificity was 100% (95% CI, 98% - 100%). The area under the summary receiver operator characteristic curve was 0.84 (95% CI, 0.77 – 0.89). The PPV of the no-biopsy approach to identify patients with coeliac disease was 68%, 90%, 96%, and 99% if coeliac disease prevalence was 1%, 4%, 10% and 30%, respectively. Between-study heterogeneity was moderate (I²=25%), and additional sensitivity analyses did not significantly alter our findings.

Conclusion

The results of this meta-analysis support the adoption of the no-biopsy approach to diagnose adult patients with coeliac disease in secondary care settings, where the pre-test probability of coeliac disease is high. Biopsy could be avoided in almost one-in-three patients referred to gastroenterology with suspected coeliac disease. Our findings may inform future guidelines for the diagnosis of coeliac disease in adults.

Introduction

While wide-scale screening for celiac disease (CeD) is increasingly being considered, its overall benefits are not well established.

Aims & Methods

We investigated the general health at diagnosis and long-term outcomes in CeD patients identified through screening in a population-representative cohort. Comprehensive health data from individuals participating in the nationally representative Health 2000 survey (N=6,376) were analyzed using registry data and interviews. Additionally, blood was collected to measure tissue transglutaminase antibodies (TGA) and endomysial antibodies (EmA) if TGA was positive, as well as other laboratory parameters. Altogether, 3254 subjects participated in a follow-up study in 2011. Mortality among subjects in the Health 2000 cohort was evaluated at the 17-year follow-up using the national statistics registry.

Results

Ninety CeD patients were identified in 2000, of whom 54 participated in the follow-up in 2011 while on a gluten-free diet. At diagnosis, patients more often had pre-eclampsia (13% vs. 5%, p=0.016), and lower levels of hemoglobin (median 140 vs 143 g/L, p=0.046), ferritin (29 vs 68 ng/mL, p<0.001), total cholesterol (5.4 vs 5.9 mmol/L, p<0.001), apolipoprotein A1 (1.40 vs 1.57 g/L, p<0.001) and apolipoprotein B (1.16 vs 1.21 g/L, p=0.009) compared to seronegative population. The groups did not differ in age (48 vs 51 years, p=0.159), sex (females 62% vs 56%, p=0.205), BMI (26 vs 26, p=0.567), blood pressure (131/81 mmHg vs 132/82 mmHg, p=0.230), or the presence of other gastrointestinal diseases, cardiovascular and psychiatric diseases, osteoporosis, malignancies, or smoking and alcohol consumption. No significant changes in cholesterol or apolipoprotein levels, mental health, or health care utilization were observed among CeD patients during the 11-year follow-up. The patients had a lower mortality rate compared to non-CeD individuals after 17 years with borderline significance (14.1% vs. 25.6%, p=0.059).

Conclusion

Population-representative individuals with screen-detected celiac disease exhibit a more favorable metabolic profile, but have lower hemoglobin and iron levels and a higher prevalence of pre-eclampsia at diagnosis. Gluten-free diet does not appear to cause adverse effects. Screen-detected patients may also have a reduced long-term mortality, although further research is needed.

Introduction

Anti-tissue transglutaminase IgA antibodies (tTG) are used in the follow-up of celiac disease (CD) to assess adherence to a gluten-free diet (GFD). Persistent positivity may indicate the need for histological reassessment. There is limited information about the rate of complete normalization of tTG and associated factors. Our objective was to evaluate the percentage, kinetics, and factors related to tTG normalization.

Aims & Methods

This was a retrospective observational study including patients with tTG testing at diagnosis and follow-up monitoring of these antibodies from 1991 to 2023 in a specialized unit dedicated to patients with CD. Inclusion criteria were: patients over 16 years of age at diagnosis, initially elevated tTG titres, and at least one serological follow-up after starting a GFD. Time to tTG normalization was estimated using the Kaplan-Meier method. Comparisons between groups were performed using the log-rank test. The association between demographic and clinicopathological characteristics at diagnosis and time to tTG normalization was assessed using Cox regression analysis.

Results

A total of 179 patients were included (75% female, mean age 40 ± 16 years). Duodenal atrophy was present in 81%, and 79% had symptoms. 83% strictly adhered to a GFD. Median follow-up was 3 years. The incidence rate of tTG normalization was 35% per patient-year. The cumulative tTG normalization rate was 38% (95% CI: 30-45) at 1 year, 61% (53-69) at 2 years, 70% (63-77) at 3 years, 80% (73-87) at 4 years, 81% (74-89) at 5 years, and 95% (88-100) at 10 years. The median time to tTG normalization was 24 months (95% CI: 20–28). Table 1 shows Kaplan–Meier estimates expressed as percentages of tTG normalization by adherece to GFD and baseline tTG. In the multivariable analysis, two factors were found to be significantly associated with the normalization of tTG: lower baseline tTG and good adherence to a GFD. Regarding baseline tTG level, patients with titres ≤ 286 U/ml (median) had 2.46 times higher likelihood of antibody normalization compared to those with higher titres (HR: 2.46; 95% CI: 1.69–3.56; p < 0.001). Regarding adherence to a GFD, patients who followed a strict GFD had 5.38 times higher likelihood of tTG normalization (HR: 5.38; 95% CI: 2.79–10.36; p < 0.001).

Table 1. Kaplan–Meier estimates expressed as percentages of normalization (with 95% CIs) after CD diagnosis, by adherece to GFD and baseline tGA titres.

Conclusion

1. The incidence rate of tTG normalization in CD patients after initiating a GFD was 35% per patient-year of follow-up.
2. In the long-term (10 years), 95% of CD patients achieved tTG normalization.
3. Lower tTG titres at diagnosis and good adherence to the GFD were predictive factors for tTG normalization.
4. Understanding the kinetics of tTG normalization according to various factors is essential before considering histological reassessment for suspected poor disease progression.