Document resource
Introduction Prolonged wireless pH monitoring enables a more conclusive assessment of GORD by accounting for day-to-day variability in acid exposure. However, the optimal analytical approach for prolonged wireless monitoring remains uncertain. Average Day analysis calculates the mean acid exposure time (AET) across all recording days. Dominant Pattern analysis classifies individual days as positive (AET >6%) or negative (AET <4%), with the final diagnosis determined when two or more days fall into the same category. Los Angeles (LA) grades B, C, and D oesophagitis are considered conclusive for a GORD diagnosis (Lyon Consensus 2.0). This study compared the diagnostic performance of both methods and evaluated whether our previously defined reference ranges outperform Dominant Day analysis. 1Methods We studied 944 consecutive patients completing 96-hour wireless pH studies (off proton pump inhibitors ≥7 days) at a tertiary referral centre over 10 years, plus 39 healthy asymptomatic controls. Receiver operating characteristic (ROC) compared Average Day versus Dominant Pattern for discriminating people without reflux from LA B/C/D oesophagitis (n=75). Area under the ROC curve (AUC) comparison used DeLong test. Performance was assessed against Dominant Day analysis and our defined 96-hour ranges (pathologic Average Day AET>4.3%). Secondary analysis was performed on LA C/D oesophagitis (n=15, Average Day AET threshold >4.7%).Results In primary analysis (LA B/C/D, n=75), Average Day demonstrated superior discrimination versus Dominant Pattern (AUC 0.953 vs 0.867, ΔAUC=0.086, 95% CI 0.040-0.137, p=0.0002) ( figure 1). Using our previously defined reference ranges, the Average Day sensitivity improved from 73.3% to 86.7% with 94.9% specificity (p=0.004), detecting 10 additional erosive oesophagitis patients. In secondary analysis (LA C/D, n=15), the Average Day achieved AUC 0.991 versus Dominant Pattern AUC 0.933 (p=0.15), achieving 93.3% sensitivity versus 86.7% at Dominant Day (1 additional patient detected).Conclusion Average Day AET at a threshold of 4.3% demonstrates superior discrimination compared with Dominant Pattern analysis for identifying conclusive GORD defined by LA B, C and D oesophagitis, with higher sensitivity while maintaining high specificity. These findings support Average Day analysis as the preferred method for interpreting 96-hour wireless pH monitoring and suggest that an Average Day AET threshold of >4.3% should be incorporated into future Lyon Consensus diagnostic criteria.Reference Rusu RI, Fox MR, Tucker E, et al. Validation of the Lyon classification for GERD diagnosis: acid exposure time assessed by prolonged wireless pH monitoring in healthy controls and patients with erosive oesophagitis. Gut. 2021;70:2230–2237.Abstract FP34 Figure 1