Adult patients with immunoglobulin (Ig)A antitissue transglutaminase (tTg) antibody (IgA-tTg) levels at least 10 times the upper limit of normal (ULN) and a moderate to high pretest probability of celiac disease may be diagnosed without endoscopy and duodenal biopsy, according to study results published in Gastroenerology.
Current guidelines recommend obtaining a duodenal biopsy to confirm a diagnosis of celiac disease; however, many studies have found high IgA-tTg antibody levels to be a noninvasive indicator of celiac disease.
To assess the current body of knowledge about the reliability of using IgA-tTg antibody levels in celiac disease diagnosis, investigators performed a systematic review and meta-analysis. A total of 18 studies comprising 12,103 individuals from 15 countries were included in the study.
The overall rate of biopsy-proven celiac disease was 62% (95% CI, 40%-83%; I2=99.9%) and the rate of IgA-tTg antibody levels at least 10 times the ULN was 32% (95% CI, 24%-40%; I2=99.3%).
Using IgA-tTg antibody levels at least 10 times the ULN to diagnose celiac disease had an area under the summary receiver operating characteristic curve of 0.83 (95% CI, 0.77-0.89), sensitivity of 51% (95% CI, 42%-60%), specificity of 100% (95% CI, 98%-100%), positive predictive value (PPV) of 98% (95% CI, 96%-99%), and negative predictive value (NPV) of 62% (95% CI, 61%-63%).
The PPV of no-biopsy celiac disease diagnosis was 65% if the prevalence of celiac disease was 1%, 88% if the prevalence was 4%, 95% if the prevalence was 10%, and 99% if the prevalence was 40%.
Results from a sensitivity analysis that included 13 studies that reported the prevalence of Marsh 3 lesions on duodenal biopsies returned similar findings as the diagnostic accuracy of using elevated IgA-tTg antibody levels (sensitivity, 51%; specificity, 100%).
Study limitations include the inability to generalize results to primary care, as all studies were conducted in secondary and tertiary care settings.
“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,” study authors noted. “This has significant implications for clinical practice by reducing the diagnostic delays, risks and healthcare costs associated with endoscopy.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
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