Symptom association analysis is important in GERD patients undergoing endoscopic therapy

To the Editor: We read the article by Koch et al1 on the safety and efficacy of endoluminal full-thickness gastroplication (the Plicator) in patients with GERD. The authors evaluated 36 patients who were refractory to proton pump inhibitors (PPIs), using impedance pH off-therapy before and after gastroplication (n = 20). GERD was diagnosed in case of (1) total number of reflux events >73, (2) composite pH DeMeester score >14.7, or (3) positive symptom index (SI) for symptoms reported at least 3 times. The Plicator significantly improved quality of life and reflux symptoms and markedly reduced esophageal acid exposure time, proximal migration of refluxate, and both acidic reflux and weakly acidic reflux (WAR) events. This study provides relevant novel data on the potential use of endotherapy for PPI-refractory GERD patients, but the interpretation of the findings would have improved if the results of symptom association analysis before and after gastroplication had also been reported. Impedance pH permits the measurement of all types of reflux and increases the diagnostic yield by use of the symptom association analysis as symptom index or symptom association probability (SAP) (2-4). In fact, several studies have shown that GERD patients, in particular those with nonerosive reflux disease, frequently have a normal acid exposure time.2, 3, 4 and 5 Using these parameters, we observed that GERD patients have symptoms associated with WAR, and this may explain the PPI failure,3 and 5 thus supporting the use of alternative surgical or endoscopic therapies. So, data concerning the symptom index for acidic reflux and WAR should also be reported preoperatively in all studies evaluating the efficacy of endoscopic procedures in GERD patients to show whether they are hypersensitive to WAR. This would increase the role of surgical or endoscopic therapies in the control of this kind of reflux, which can be diagnosed only by impedance pH testing. Accordingly, we recommend that Koch et al1 report the preoperative results of the symptom index for both acidic reflux and WAR in their future studies.