The relevance of reflux monitoring off therapy.

To The Editors: We read the recent article by Vaezi MF. (1) with interest. The Author discussed on the opportunity to evaluate patients with symptoms suggestive of gastro-oesophageal reflux (GERD) by means of 24-h pH or impedance-pH monitoring On or Off therapy. He concluded that, after an empiric trial with twice-daily PPI therapy, in case of refractoriness, patients should undergo reflux monitoring On therapy in order to exclude reflux disease, while testing Off therapy has a limited value, because in this group it results only in an additional test proving what is already established by patients’ lack of response to aggressive PPI therapy. We agree that an empiric treatment with a twice daily PPI trial is the correct initial approach to patients with suspected GERD and testing should be reserved only to those with persisting symptoms despite antisecretory drugs. However, we believe that a particular attention must be taken when considering the endoscopy-negative population. We have recently observed that patients with non-erosive reflux disease (NERD) evaluated using impedance-pH monitoring Off therapy (2) have frequently symptoms related to weakly acidic reflux, mainly in case of normal esophageal acid exposure. This appears a relevant point, in that we are now able to subtract this subgroup of patients with weakly acidic reflux disease from those without any reflux underlying their symptoms (functional heartburn, FH). These two subgroups require completely different therapeutic approaches (surgery or pain-modulators), although limited outcome data are available in this field (3,4). On the other hand, a recent study (4) has shown that NERD patients refractory to PPIs can equally respond to surgery. In the endoscopy-negative population the risk of including FH in NERD is rather high and we have shown that PPI therapy may cause an underestimation of GERD patients (inability to identify weakly acidic reflux patients) and an overestimation of FH patients (placebo effect) (5). These findings have been confirmed in a recent investigation, in which the analysis of PPIs response in a large number of endoscopy-negative patients with heartburn revealed that those patients with normal acid exposure and positive symptom association had a 50% response to PPIs (6). Therefore, we confirmed that the negative response to PPI therapy does not mean immediately that reflux can be excluded. Overall, in our opinion, impedance-pH testing On therapy is more indicated in patients with proven reflux disease (erosive esophagitis, Barrett’s esophagus, previous abnormal pH-metry), while endoscopy-negative patients not responding to PPIs should be better assessed Off antisecretory therapy in order to be sure that they have GERD or not.