Certain adult patients with suspected coeliac disease might not require invasive endoscopy and duodenal biopsy for an accurate diagnosis, data suggest.
The UK researchers said their systematic review and meta-analysis was the first to evaluate the accuracy of the no-biopsy approach, which could lead to shorter diagnosis times, increased patient satisfaction and reduced healthcare costs.
They found that IgA anti-tissue transglutaminase (tTg) antibody levels of 10 or more times the upper limit of normal (ULN) were highly indicative of coeliac disease in adults with a 100% specificity and a positive predictive value of 98%.
Although the value varied according to the pre-test probability of coeliac disease.
The meta-analysis involved 18 studies of more than 12,000 participants from 15 countries, with a pooled prevalence of biopsy-proven coeliac disease of 62%.
The proportion of patients with IgA-tTG ≥10×ULN was 32%.
Results showed that the overall summary sensitivity of IgA-tTG ≥10×ULN was 51% and the summary specificity was 100% for the detection of coeliac disease. The area under the summary receiver operating characteristic curve was 0.83.
The positive predictive value of the no-biopsy approach was 65%, 88%, 95%, and 99% if coeliac disease prevalence was 1%, 4%, 10% and 40%, respectively.
The results suggested that select adult patients who met the very high antibody levels and had a moderate to high pre-test probability of coeliac disease could be diagnosed without undergoing further invasive investigations, the researchers said.
The between-study heterogeneity was moderate and additional sensitivity analyses that excluded three studies that had been published as letters did not significantly alter the findings, said the authors from the Sheffield Teaching Hospitals, UK.
“The results of this study demonstrate that the no-biopsy approach, that has been incorporated in paediatric practice to diagnose coeliac disease for over a decade, can be safely extrapolated to selected adult patients in secondary care settings,” they wrote in Gastroenterology [link here].
“This has significant implications for clinical practice by reducing the diagnostic delays, risks and healthcare costs associated with endoscopy. In a recent study, we estimated that the cost of diagnosis in adults could be reduced by over 75% if endoscopy and biopsy were avoided.”
However, they also acknowledged exisiting concerns with the approach, including the possibility of false-positive diagnosis when relying on serology testing alone and the lack of standardisation of IgA-tTG assays across the different laboratories.
But the researchers said their study found high diagnostic performance of IgA-tTG ≥10×ULN across different commercial kits, laboratories and countries.
“Importantly, it should be stressed that endoscopy would still be required for patients with <10 fold elevation of IgA-tTG, patients with red flag signs or symptoms and for those who wish to have a confirmatory biopsy before adhering to a lifelong gluten-free diet.”
That authors noted that all studies were conducted in secondary and tertiary care settings, and therefore their results might not be generalisable to primary care.