RT Journal Article SR Electronic T1 Application of Lyon Consensus criteria for GORD diagnosis: evaluation of conventional and new impedance-pH parameters JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 1062 OP 1067 DO 10.1136/gutjnl-2021-325531 VO 71 IS 6 A1 Frazzoni, Leonardo A1 Frazzoni, Marzio A1 De Bortoli, Nicola A1 Ribolsi, Mentore A1 Tolone, Salvatore A1 Russo, Salvatore A1 Conigliaro, Rita Luisa A1 Penagini, Roberto A1 Fuccio, Lorenzo A1 Zagari, Rocco Maurizio A1 Savarino, Edoardo YR 2022 UL http://gut.bmj.com/content/71/6/1062.abstract AB Objective To validate Lyon Consensus criteria for diagnosing gastro-oesophageal reflux disease (GORD) by reflux monitoring.Design Manual review of impedance-pH tracings from patients with proton pump inhibitor (PPI)-dependent heartburn, evaluated off PPI. Acid exposure time (AET) thresholds defined by the Lyon Consensus and impedance parameters were investigated, namely, total refluxes (TRs), postreflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI).Results The study included 488 patients, 178 (36%) with normal (<4%) AET, 89 (18%) with inconclusive (4%–6%) AET and 221 (45%) with abnormal (>6%) AET, alongside with 70 healthy controls. At receiver operating characteristic analysis, area under curve was 0.89, 0.95 and 0.89 for TRs, PSPW index and MNBI, respectively, and threshold values were 40, 50% and 2000 Ω; the 4% physiological AET threshold defined by the Lyon Consensus showed 100% specificity but 63% sensitivity. The thresholds defined for impedance parameters were validated against AET by means of ordered logistic regression, being in concordance with the 4% AET threshold (OR 2.5 for TRs, 18.9 for PSPW index and 5.7 for MNBI). TRs positivity and concordant PSPW index/MNBI positivity were found in 80%–90% of patients in the abnormal AET group, in 73%–74% of cases in the inconclusive AET group and in 28%–40% of cases in the group with normal AET.Conclusions Our results show the overall validity of the Lyon Consensus approach to GORD diagnosis. Adding evaluation of impedance parameters, namely, TRs, PSPW index and MNBI to AET appraisal, substantially improves the diagnostic yield of reflux monitoring.Data supporting the study are available on reasonable request from the corresponding author.