Autofluorescence Imaging Endoscopy for Predicting Acid Reflux in Patients with Gastroesophageal Reflux Disease

Background and Aim: Endoscopic diagnosis of gastroesophageal reflux disease (GERD) remains challenging. Autofluorescence imaging (AFI) can identify indistinct mucosal lesions; however, its ability to diagnose GERD has not been determined. This study aimed to compare the diagnostic capabilities of standard white light imaging (WLI) and AFI using pH/impedance testing as gold standard.Methods: In this prospective observational trial, 95 consecutive patients with classic reflux symptoms were screened in two tertiary care referral hospitals and 82 were included. GerdQ questionnaire was administered to each patient. Endoscopy with WLI and AFI, and ambulatory 24-h pH/impedance monitoring were performed. Erosive esophagitis on WLI was defined as positive for GERD, whereas on AFI endoscopy, the appearance of one or more longitudinal purple lines > 1 cm was defined as indicative of GERD. We assessed the diagnostic capacities of each method, as well as inter-observer agreement on AFI findings. We also looked at factors associated with having a positive AFI finding.Results: The sensitivity and accuracy of AFI (77% and 67%, respectively) in detecting GERD were higher than those of WLI (21% and 52%, respectively), although the specificity of AFI (53%) was lower than that of WLI (97%); McNemar test showed a significant difference (P = 0.000). Inter-observer reliability analysis of AFI findings indicated substantial agreement (Kappa = 0.630, P = 0.000). Multivariate analysis showed that abnormal AFI findings significantly correlated with positive pH/impedance result (odds ratio = 0.242, 95% confidence interval = 0.087-0.673, P = 0.007).Conclusions: AFI can reveal GERD-related mucosal changes, invisible on conventional WLI, thus improve the endoscopic diagnosis of GERD.