Editorial: Do We Need to Adapt GERD Metrics Based on the Population Being Evaluated?

In patients with suspected gastroesophageal reflux disease (GERD), especially before long-term medical or invasive treatment, objective evidence of reflux disease is essential because symptoms alone are insufficient for diagnosis [1]. Furthermore, symptom perception may overlap with disorders of gut-brain interaction and oesophageal hypersensitivity syndromes, complicating clinical interpretation [2, 3]. According to Lyon Consensus 2.0, acid exposure time (AET) > 6% on ambulatory reflux monitoring performed off therapy provides conclusive evidence of GERD [1]. In this issue of Alimentary Pharmacology & Therapeutics, Chan et al. evaluated the relationship between reflux symptoms and objective reflux burden in Asian and U.S. patients undergoing pH-impedance monitoring [4]. Despite lower acid exposure among Asian patients (mean AET 2.19% vs. 3.53%), symptom burden was significantly higher, particularly when assessed using the Global Symptom Severity (GSS) scale [5]. Regurgitation predominated in Asian patients, whereas heartburn was more common in the U.S. cohort. Importantly, lowering the AET threshold to 4% increased GERD diagnostic yield more substantially in Asian patients, supporting the lower pathological threshold proposed by the Seoul Consensus for Asian populations [6]. The study has important strengths, including standardized reflux monitoring, use of contemporary Lyon 2.0 metrics, and incorporation of adjunctive impedance parameters such as mean nocturnal baseline impedance (MNBI) and total reflux episodes (TRE). Moreover, after propensity score matching and multivariable analysis, Asian ethnicity remained independently associated with higher symptom burden. However, several limitations warrant caution. First, the study was conducted in tertiary motility centres, introducing potential referral bias. Care pathways also differed between regions: most U.S. patients were proton pump inhibitor non-responders, whereas Asian patients were largely treatment-naïve. Second, the cohorts differed substantially in age, sex distribution, and body mass index, all factors known to influence reflux physiology and symptom perception. Another important consideration is symptom assessment itself. The largest differences between populations were observed with GSS, a broad visual analogue scale that may capture non-GERD symptoms, including dyspeptic or psychological symptoms. In contrast, differences in GERDQ were modest. Oesophageal hypervigilance, reflux hypersensitivity, functional dyspepsia, and cultural differences in symptom reporting may therefore contribute to the observed discrepancy between symptoms and reflux burden [2, 3, 7]. Furthermore, regurgitation predominance in Asian patients also raises the possibility of behavioural disorders such as rumination syndrome [8, 9], particularly because symptom-reflux association analysis and comprehensive manometric evaluation were unavailable. Nevertheless, the findings align with prior evidence demonstrating lower normal AET values in Asian populations. A systematic review including 19 Asian studies reported an upper normal AET limit of 3.2% in healthy Asian subjects [10], supporting the ≥ 4% threshold proposed by the Seoul Consensus. These observations reinforce the concept that reflux metrics may not be universally interchangeable across populations. In conclusion, Chan et al. demonstrate important differences in GERD symptom burden and reflux physiology between Asian and U.S. populations. Their findings support the need for further prospective studies evaluating whether population-adapted reflux thresholds improve diagnostic accuracy and therapeutic outcomes in GERD. Javier Chahuán: conceptualization, investigation, writing – original draft. Edoardo Vincenzo Savarino: conceptualization, investigation, writing – review and editing, project administration. The authors have nothing to report. Javier Chahuán has nothing to declare. Edoardo Vincenzo Savarino has served as speaker for AbbVie, Agave, AGPharma, Alfasigma, Aurora Pharma, CaDiGroup, Celltrion, Dr. Falk, EG Stada Group, Fenix Pharma, Fresenius Kabi, Galapagos, Janssen, JB Pharmaceuticals, Innovamedica/Adacyte, Malesci, MayolyBiohealth, Omega Pharma, Pfizer, Reckitt Benckiser, Sandoz, SILA, Sofar, Takeda, Tillots, and Unifarco; has served as consultant for AbbVie, Agave, Alfasigma, Biogen, Bristol-Myers Squibb, Celltrion, Diadema Farmaceutici, Dr. Falk, Fenix Pharma, Fresenius Kabi, Janssen, JB Pharmaceuticals, Merck & Co, Nestlé, Reckitt Benckiser, Regeneron, Sanofi, SILA, Sofar, Synformulas GmbH, Takeda, and Unifarco; and has received research support from Pfizer, Reckitt Benckiser, SILA, Sofar, Unifarco, and Zeta Farmaceutici. This article is linked to Chan et al. papers. To view this article, visit https://doi.org/10.1111/apt.70713. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.