BACKGROUND: Symptoms and reflux burden in gastroesophageal reflux disease (GERD) may vary between populations.

AIMS: To evaluate relationships between symptom profiles and objective reflux burden in patients in two world regions, Asia and the United States.

METHODS: This was a cross-sectional study of patients undergoing pH-impedance monitoring from one Asian and two US centres. Validated patient-reported symptom instruments were prospectively collected. Symptom characteristics were compared against objective reflux burden (acid exposure time, AET; total reflux episodes, TRE; mean nocturnal baseline impedance, MNBI) from pH-impedance monitoring between the two populations.

RESULTS: Of 1099 patients, 162 were in Asia (age 47.4 ± 1.1 years, 36.4% female, body mass index, BMI 24.2 ± 0.4 kg/m2) and 937 in the United States (53.1 ± 1.3 years, 67.7% female, BMI 30.1 ± 0.3 kg/m2). Regurgitation dominated in Asia (59.9% vs. 50.3% heartburn in the United States), with higher TRE (55.4 ± 2.4 vs. 46.4 ± 1.2, p < 0.001). Despite this, reflux burden was lower in Asia (mean AET 2.19% ± 0.4% vs. 3.53% ± 0.2%; pathologic AET 11.1% vs. 20.5%; MNBI 2472 ± 62 Ω vs. 1745 ± 81 Ω; conclusive GERD per Lyon 2.0: 13% vs. 25.7%) (all p < 0.001), with higher symptom burden (GERDQ 8.97 ± 0.2 vs. 8.44 ± 0.1, p < 0.05; global symptom severity, GSS: 65.1 ± 1.8 vs. 48.1 ± 1.1, p = 0.001). Changing the AET threshold to 4% increased diagnostic yield by 21% among Asians (p = 0.035 vs. US). On multivariable linear regression, Asian patients (β = 19.3, p < 0.0001), higher AET (β = 1.02, p = 0.0004), higher reflux episodes (β = 0.11, p = 0.0029), lower BMI (β = -0.37, p = 0.0046) and female sex (β = 8.14, p = 0.0007) were independent predictors for higher GSS.

CONCLUSIONS: Compared to US patients, GERD profiles in Asian patients associate with higher symptom reporting despite lower objective reflux burden.