The Lyon Score, a Novel GERD Scoring System, Significantly Predicts Response to PPIs in GERD Patients With Chronic Cough

Background Chronic cough is a frequent and troublesome extraesophageal manifestation of GERD, with poor response rates to proton pump inhibitors (PPIs) and limited diagnostic tools to predict treatment efficacy. The Lyon score, a novel composite metric integrating reflux parameters, has shown promise in typical GERD but remains untested in chronic cough. Aim To evaluate the ability of the Lyon score to predict symptomatic response to double‐dose PPI therapy in patients with suspected GERD‐related cough. Methods We retrospectively analyzed 232 adult patients with chronic cough undergoing upper endoscopy, high‐resolution manometry, and 24 h impedance‐pH monitoring. PPI response was defined as ≥ 50% reduction in cough severity after ≥ 8 weeks of double‐dose PPI therapy. Results Among 232 patients, 94 (40.5%) responded to PPIs. Responders had significantly higher Lyon scores (median 7.5 vs. 2.5, p < 0.0001). The Lyon score showed strong predictive performance (AUC 0.769), superior to AET (AUC 0.718) and reflux episodes (AUC 0.602), and comparable to MNBI < 1500 Ω (AUC 0.798). A Lyon score ≥ 5 had 64% sensitivity and 83% specificity. MNBI < 1500 Ω yielded 67% sensitivity and 79% specificity. The combination Lyon score or MNBI < 1500 Ω achieved optimal diagnostic accuracy (sensitivity 79%, specificity 71%, Youden index 0.50), significantly outperforming the combination Lyon score or AET > 6% ( p < 0.0001). AET > 6% remained highly specific (93%) but had poor sensitivity (43%). Conclusion The Lyon score is a useful tool to identify GERD‐related chronic cough responsive to PPI therapy. The presence of low MNBI further improves the prediction of PPI response, supporting integration in reflux work‐up for chronic cough.