Validation of the Lyon classification for GORD diagnosis: acid exposure time assessed by prolonged wireless pH monitoring in healthy controls and patients with erosive oesophagitis

Abstract

ObjectiveAcid exposure time (AET) from ambulatory pH studies and reflux oesophagitis are independent measurements used by the Lyon classification to diagnose GORD. This study aimed to validate AET reference ranges and diagnostic thresholds by analysis of 96-hour wireless pH studies from healthy, asymptomatic controls (HCs) and patients with and without oesophagitis.DesignHC and consecutive patients referred for wireless pH studies (off acid suppressants for >7 days) underwent 96-hour pH studies at two tertiary referral centres. Erosive oesophagitis was categorised by the Los Angeles (LA) classification. Linear regression and receiver operating curve (ROC) analysis were performed to define optimal diagnostic cut-offs.ResultsProlonged, 96-hour pH studies were completed in 39 HCs (age 28 (18–53) years, 72% female) and 944 patients (age 46 (16–85) years, 65% female), of whom 136 (14.5%) had reflux oesophagitis. Median AET in HC was 1.3% (upper 95th percentile 4.6%) for any study day and 2.6% (upper 95th percentile 6.9%) for the worst day (24-hour period) during the study. ROC analysis for average AET differentiated HC from patients with moderate-to-severe oesophagitis (LA BCD; sensitivity 87%, specificity 95%, positive predictive value (PPV) 59%, negative predictive value 99% for a cut-off AET of 4.3%; area under the receiver operating curve 0.95). Specificity was higher, but PPV was substantially lower for severe oesophagitis (LA CD). ‘Worst-day’ analysis provided similar results; however, day-to-day variability was high.ConclusionDiagnostic thresholds for average AET were identified that accurately discriminate between HCs and patients with erosive oesophagitis. The findings provide conditional support for diagnostic criteria for GORD proposed by the Lyon Consensus.

Clinical role of ambulatory reflux monitoring in PPI non‐responders: recommendation statements

“…On the other hand, patients with pathologic acid exposure (AET >6.0%) on two or more days of monitoring are expected to benefit from optimised lifestyle and pharmacologic anti‐reflux management. Patients with very high levels of acid exposure (AET >10%) may be less responsive to only lifestyle and pharmacologic management, particularly in the setting of a large hiatal hernia and/or bipositional/nocturnal GERD, and may require escalation of GERD management 39 …”

“…Patients with very high levels of acid exposure (AET >10%) may be less responsive to only lifestyle and pharmacologic management, particularly in the setting of a large hiatal hernia and/or bipositional/nocturnal GERD, and may require escalation of GERD management. 39 There was less certainty regarding standardisation of the interpretation of pH-impedance on PPI therapy. Based on recent data, the group agreed on two recommendations regarding pH impedance on PPI, the definition of PPI-controlled GERD (AET <2.0%, <40 reflux events and a negative reflux symptom association) and a definition of PPI refractory GERD (AET >4.0% and a positive reflux symptom association).…”

Characterisation of patients with supine nighttime reflux: observations made with prolonged wireless oesophageal pH monitoring

“…Periods in the supine position during the day (ie, naps) were excluded from the analysis. Total acid exposure was considered pathological if it was found to be >6% and supine nocturnal acid exposure was defined as pathological if >1.5% 16 . Variance was calculated as the deviation of the 24‐, 48‐ or 72‐hour values from the overall 96‐hour result and the coefficient of variation was calculated as the ratio of the standard deviation to the mean.…”

“…Total acid exposure was considered pathological if it was found to be >6% and supine nocturnal acid exposure was defined as pathological if >1.5%. 16 Variance was calculated as the deviation of the 24‐, 48‐ or 72‐hour values from the overall 96‐hour result and the coefficient of variation was calculated as the ratio of the standard deviation to the mean. The Symptom Index (SI) was calculated as the percentage of symptoms related to reflux (diagnostic cut‐off >50%).…”

Editorial: wireless pH‐monitoring—is it time to put away the pH‐impedance catheters?

“…First, combined pH–impedance studies acquired measurements of acid and non‐acid reflux events which, together with the introduction of novel metrics, increased diagnostic sensitivity 1 . More recently, prolonged ambulatory monitoring by wireless pH sensors placed at endoscopy has improved diagnostic consistency 2,3 . An additional advantage of wireless technology over catheter‐based techniques is reduced interference in daily activities and eating 4 .…”