A prediction model of abnormal acid reflux in gastroesophageal reflux disease

Abstract Background and Aim The measurement of esophageal acid exposure time (AET) using combined multichannel intraluminal impedance–pH (MII‐pH) tests is the gold standard for diagnosing gastroesophageal reflux disease (GERD). However, this catheter‐based 24‐h test can cause considerable patient discomfort. Our aim is to identify factors affecting AET and to develop a scoring model for predicting AET abnormalities before conducting the MII‐pH test. Methods Of the 366 patients who underwent MII‐pH test at two facilities in Japan and Vietnam, 255 patients who also had esophagogastroduodenoscopy and high‐resolution manometry were included in this study. Logistic regression analysis was conducted using risk factors for AET > 6% identified from a derivation cohort ( n = 109). A scoring system predicting AET > 6% was then constructed and externally validated with a separate cohort ( n = 146). Results Three variables were derived from the prediction model: male gender, Hill grades III–IV, and weak mean distal contractile integrals. Based on these scores, patients were classified into low (0 point), intermediate (1–3 points), and high (4 points) risk groups. The probabilities of having an AET > 6% were 6%, 34%, and 100% for these groups, respectively. A score of < 1 excluded patients with abnormal AET, with a negative predictive value of 93.8% in the derivation cohort and 80.0% in the validation cohort. Conclusions We derived and externally validated a prediction model for abnormal AET. This system could assist in guiding the appropriate treatment strategies for GERD.