Endoscopic techniques for the identification of duodenal villous atrophy in celiac disease: a systematic review and meta-analysis of diagnostic accuracy

Background and aims: Celiac disease is characterized by villous atrophy (VA), which requires duodenal histology for diagnosis. Endoscopic signs can prompt suspicion of VA and help target biopsies. Many endoscopic techniques for detecting VA have been studied, with heterogeneous results. This systematic review and meta-analysis aimed to evaluate the accuracy of different endoscopic techniques for identifying VA. Methods: A literature search of PubMed and Embase for eligible articles was conducted according to the Preferred Reporting Items for a Systematic Review and Meta-Analysis guidelines. Summary sensitivity and specificity were calculated using bivariate random-effects models for each endoscopic technique. The protocol was preregistered on Open Science Framework (doi:10.17605/OSF.IO/SKFB5). Results: A total of 22,074 records were screened, and 52 articles were eligible. Standard white-light endoscopy (WLE) showed high summary specificity (95.3%; 95% CI, 89.9%-97.9%) but lower sensitivity (81.4%; 95% CI, 72.3%-87.9%). The best results were shown by the water-immersion technique (sensitivity, 95.2%; 95% CI, 88.5%-98.1%; specificity, 98.4%; 95% CI, 95.3%-99.4%), narrow-band imaging (NBI) (sensitivity, 92.1%; 95% CI, 84.6%-96.2%; specificity, 93.9%; 95% CI, 91.2%-95.8%), and dye-based chromoendoscopy (sensitivity, 94.8%; 95% CI, 90.6%-97.2%; specificity, 93.5%; 95% CI, 86.9%-96.9%). White-light magnification endoscopy showed high sensitivity (88.4%; 95% CI, 80.8%-93.3%) but low levels of specificity (70.2%; 95% CI, 66.3%-81.1%). Compared with standard WLE, i-scan showed similar sensitivity (80.1%; 95% CI, 64.6%-89.8%) but slightly lower specificity (90.0%; 95% CI, 80.5%-95.1%). Confocal endomicroscopy also showed good sensitivity (87.4%; 95% CI, 64.2%-96.4%) and specificity (90.7%; 95% CI, 65.3%-98.1%). Heterogeneity was low (I2 < 30%) for all endoscopic modalities. Conclusions: Compared with WLE, advanced techniques such as water immersion, NBI, and dye-based chromoendoscopy offer improved sensitivity, particularly for subtle, patchy lesions.