Validation of the Milan Score Using Prolonged Wireless PH Monitoring

BACKGROUND AND AIM: In 2024, a novel high-resolution manometry (HRM) metric termed the Milan Score was introduced to quantify anti-reflux barrier disruption and estimate the probability of pathologic gastroesophageal reflux disease (GERD). This composite score incorporates oesophagogastric junction (EGJ) barrier metrics, oesophageal motor function and response to the straight leg raise (SLR) manoeuvre. Prior validations relied on acid exposure time (AET) > 6% on 24-h pH-impedance studies, making the outcome susceptible to day-to-day variability. The aim of this study is to validate the effectiveness of the Milan Score in predicting GERD using 96-h wireless pH-monitoring. METHODS: Data from consecutive adults with GERD symptoms undergoing HRM and 96-h wireless pH-monitoring (2023-2025) at IRCCS Policlinico San Donato (Italy) and Washington University in St. Louis (USA) were retrospectively collected. Milan Score was calculated automatically from HRM metrics. pH studies followed Lyon Consensus 2.0 criteria, defining conclusive GERD as AET > 6% on ≥ 2 days. Diagnostic performance was evaluated by receiver operator characteristics (ROC) analysis. RESULTS: ), 48 had conclusive GERD. Hiatal hernia prevalence (65% vs. 35%, p = 0.006) and median SLR-induced intra-oesophageal pressure increase (14 vs. 3 mmHg, p < 0.001) were higher in GERD patients. Positive Milan Score was found in 65% of GERD vs. 19% of non-GERD group (p < 0.001). Milan Score values increased with higher number of positive pH days. ROC yielded AUC of 0.812 for conclusive GERD (95% CI: 0.718-0.895, optimal threshold 151.84, sensitivity 60.4%, specificity 92.9%). CONCLUSIONS: Abnormal Milan Score reliably predicts pathologic reflux per Lyon Consensus 2.0 on 96-h wireless pH-monitoring, with performance similar to 24-h pH-impedance. This validation strengthens evidence for the Milan Score in GERD diagnosis.