Abstract
Interpreting natural course studies have been very difficult due to their retrospective design, lack of standardization, reliability of reported mucosal findings, liberal use of antireflux medications and accuracy of chart documentation. Studies provided a wide range of progression rates of patients from nonerosive reflux disease (NERD) to erosive esophagitis (EE). However, direct progression from NERD to Barrett's esophagus appears to be an uncommon phenomenon. Importantly, progression of NERD patients was commonly reported to low grades of EE, which are currently considered inconclusive of gastroesophageal reflux disease. Reports of progression rates from low grades to high grades EE also vary considerably. Progression of patients with EE, without metaplastic epithelium underneath the inflammation, to Barrett's esophagus is relatively uncommon. Recently, it was also recognized that regression from high grades to low grades EE and from EE to NERD is a common phenomenon affecting up to 25% of the patients from each group. © 2021 Lippincott Williams and Wilkins. All rights reserved.