Not All Patients With Non-erosive Reflux Disease Share Psychological Distress as Main Mechanism of Disease

TO THE EDITOR: We read with interest the study by Nam et al, who evaluated the association between irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD) and concluded that IBS is strongly linked to non-erosive reflux disease (NERD) and not with erosive esophagitis. The authors stated that the association between IBS and NERD is due to the fact that both disorders share psychological distress, such as somatization and anxiety. However, we believe that it is deceiving to refer all patients with NERD to a unique pathogenetic mechanism represented by psychological distress. This population with typical reflux symptoms represents about 70% of GERD patients and it is simplistic to diagnose them exclusively on the basis of negative endoscopy, as Nam et al have done. We have shown that NERD patients are an heterogeneous group from a pathophysiological point of view. The use of pH-impedance testing allows us to identify 3 distinct subpopulations of NERD: the first with excess acid in esophagus, the second with normal acid, but an esophagus hypersensitive to acid or non-acid or both, the third without any kind of reflux underlying symptoms. This last subgroup is called functional heartburn (FH) and must be excluded from the realm of GERD, as already acknowledged by the experts of Rome III criteria for esophageal functional disorders. We have also demonstrated that FH is significantly associated with dyspeptic symptoms pertaining to the postprandial distress syndrome, thus supporting also the fact that they are likely to be combined with IBS. Therefore, the analysis of the Nam et al. did not take into any consideration the pathophysiological complexity of NERD and this reduces substantially the strength of their conclusions. Moreover, Nam et al assessed also patients with atypical symptoms supposed to be due to reflux (hoarseness, chronic cough), but there was no mention of the methods they used in correlating them to reflux disease. It is well known that the relationship of causality between reflux and extraesophageal symptoms is a controversial issue. Finally, Nam et al reported in their discussion that an increased body mass index may contribute to favor reflux and induce symptoms in NERD patients. Once again, it has been shown that this is only true for NERD patients with abnormal acid reflux and not for FH. In conclusion, we believe that the results of the study by Nam et al should be interpreted with caution in relation to the above criticisms.