Background/AimsThe body position can influence esophageal motility data obtained with high-resolution manometry (HRM). To examine whether the body position influences HRM diagnoses in patients with esophageal dysphagia and gastroesophageal reflux disease (GERD).Methods HRM (Manoscan) was performed in 99 patients in the sitting and supine positions; 49 had dysphagia and 50 had GERD assessed by 24-hour pH monitoring. HRM plots were analyzed according to the Chicago classification. ResultsHRM results varied in the final diagnoses of the esophageal body (EB) in patients with dysphagia (P = 0.024), the result being more distal spasm and weak peristalsis while sitting. In patients with GERD, the HRM diagnoses of the lower esophageal sphincter (LES), the esophagogastric junction (EGJ) morphology, and EB varied depending on the position; (P = 0.063, P = 0.017, P = 0.041 respectively). Hypotensive LES, EGJ type III (hiatal hernia), and weak peristalsis were more frequently identified in the sitting position. The reliability (kappa) of the position influencing HRM diagnoses was similar in dysphagia and GERD ("LES diagnosis": dysphagia 0.32 [0.14-0

Increased age, overweight and central obesity pose a higher risk of GEJ type III (hiatal hernia). The greater disruption of the GEJ is associated with lower resting pressure, esophageal shortening, and higher acid exposure in the pH-monitoring.