pHoenix Score: Validation of a Novel Metric to Improve Diagnosis of Gastroesophageal Reflux Disease Using 24‐Hour pH Monitoring

Background The pHoenix score ( pHx ‐S) is a simple pH ‐monitoring metric developed to improve gastroesophageal reflux disease ( GERD ) diagnosis by integrating upright and supine acid exposure time ( AET ) to reduce “inconclusive” cases compared to AET alone. Since the pHx ‐S was derived from 48‐h wireless studies, we aimed to validate its use in transnasal catheter‐based 24‐h pH monitoring. Methods We conducted a single‐center, cross‐sectional study of patients undergoing 24‐h pH monitoring for suspected GERD (2016–2024). Diagnostic cutoffs for the pHx ‐S were ≤ 7.06 (normal), 7.06–8.45 (inconclusive), and ≥ 8.45 (pathological). Its predictive performance was validated against the DeMeester score ( DMS ) and compared to total AET . We also evaluated the impact of meal period inclusion/exclusion on the DMS , AET , and pHx ‐S. Results Of 318 individuals (199 [62.6%] women; median age, 58 [46–67] years), 170 (53.5%) presented with pathological acid exposure based on DMS . Using total AET alone, 150 (47.2%), 35 (11%), and 133 (41.8%) were classified as normal, inconclusive, and pathological, respectively. Using the pHx ‐S, 148 cases (46.5%) were classified as normal and 155 (48.7%) as pathological. Notably, only 15 cases (4.7%) were considered borderline using the pHx ‐S, a 57.1% reduction ( p = 0.015) compared to total AET . Sensitivity/specificity of the pHx ‐S were 97.6%/97.3% (lower threshold) and 91.2%/100% (upper threshold). Inclusion/exclusion of meals had minimal impact on diagnosis by DMS , AET , or pHx ‐S. Conclusions The pHx ‐S improves GERD diagnosis by reducing inconclusive cases, simplifying the calculation, accounting for the disease spectrum, and eliminating the need for meal recording compliance with comparable accuracy to the DMS .