O32 Defining normal ranges for 96-hour wireless PH monitoring using healthy controls

Introduction Technology now allows up to 96-hour wireless pH-recording in clinical practice; however, no normal values exist for this methodology. This study acquired esophageal pH recordings healthy controls (HC) and compared these against measurements patients with endoscopic evidence of gastroesophageal reflux disease (GORD). Results were used validate the Lyon Consensus Classification GORD Diagnosis. Methods HC had monitoring (Bravo) over 96 hr at two tertiary centers. Bravo was inserted under sedation endoscopy. Median 95th percentile calculated acid exposure time (AET) 24, 48, 72 96-hrs ‘worst 24-hrs’ (i.e. most pathological day). The same analysis applied results from a database consecutive erosive esophagitis (Los Angeles (LA) classification) that completed 96-hr (acid suppressants stopped ≥5-days previously). A receiver operating curve (ROC) area ROC (AUC) Youden’s index also performed define optimal cut-off AET. Results 71 asymptomatic studied, whom 47 (age 28±9 years, 66% F) recording. (upper percentile) AET 1.7% (3.0%) any day 2.9% (4.5%) worst day. 136 (61 LA A, 60 B, 12 C, 3 D) - table 1. Linear regression revealed correlation (p<0.0001, R2=33%) between findings after adjusting gender, age duration test. average hrs differentiated group (LA sensitivity 92%, specificity 75%, positive predictive value (PPV) 77%, negative (NPV) 91% 3.1%, AUC 0.91. Similar present 24-hr’ (sensitivity 91%, 79%, PPV 80%, NPV 90% 5.8%; 0.92). Conclusions defines range ambulatory monitoring. These discriminated conclusive diagnosis, based on findings. diagnostic criteria proposed by Consensus. upper limit ~4% (3.0% AET, 4.5% AET) approximately ~6% (worst 5.8% AET).