Patients with physiological acid exposure and positive symptom association scores: a distinct group within the GORD...

Studies comparing pH-metrically well-characterized gastro-oesophageal reflux disease (GORD) patients with physiological reflux to GORD patients with pathological reflux, with regard to clinical and epidemiological data, are lacking. We included 273 GORD patients with pathological 24-h pH-monitoring (pH+), defined as pH<4 > or = 6% of time. A symptom index (SI) > or = 50% was considered positive, as well as a symptom association probability (SAP) > or = 95%. We included 84 GORD patients with physiological acid exposure (pH-) and a positive SI and/or SAP. Manometry and endoscopy reports were reviewed. Subjects completed questionnaires about demographics and medical history, functional dyspepsia and irritable bowel syndrome, the Nepean Dyspepsia Index symptom score and the RAND-36 quality of life scale. pH- patients were younger (45 vs 50 years, P = 0.003), more often female (60%vs 39%, P = 0.001), smoked more (31%vs 19%, P = 0.021) and reported proton pump inhibition failure more often (47%vs 32%, P = 0.027). A hypotensive lower oesophageal sphincter was less common in pH- patients (18%vs 34%, P = 0.008) and distal oesophageal contraction amplitude was higher (11 vs 9.5 kPa, P = 0.045). pH- patients had hiatal hernia and oesophagitis less often (48%vs 73%, P < 0.0005; 36%vs 54%, P = 0.012 respectively). pH- patients less often reported no other symptoms besides GORD (20%vs 34%, P = 0.015). pH- patients scored worse at the Nepean (reflux 19 vs 12 out of 39, P < 0.0005; dyspepsia 54 vs 38 out of 156, P < 0.0005). In the subgroup of patients who have physiological oesophageal acid exposure the enhancement of the perceived symptom burden appears to be the most important mechanism in GORD pathogenesis.