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

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.

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.

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.

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.