The role of Acid in functional dyspepsia.

To The Editor: We read the recent study by Xiao et al. (1) with interest. The authors evaluated 24-h pH monitoring and response to rabeprazole (10 mg b.i.d.) for 4 weeks in 186 consecutive Functional Dyspepsia (FD) patients identified using the validated Rome III criteria (2). Subdividing FD patients on the basis of their predominant symptom, they found that those complaining of epigastric burning had the highest prevalence of abnormal reflux and the greatest response to anti-secretive therapy. These results are in keeping with those observed in a study we have recently published (3) evaluating the overlap between FD and Non-Erosive Reflux Disease (NERD) in a large population of endoscopy-negative patients. We investigated 200 patients with NERD using impedance-pH monitoring off-PPI therapy in order to clearly identify the different subgroups of patients collected under the NERD umbrella (4). Moreover we prospectively used a validated dyspepsia questionnaire to evaluate presence and severity of dyspeptic symptoms (5). We observed that NERD patients with abnormal pH (% time pH<4 > 4,2%) more frequently complained of symptoms such as epigastric pain and epigastric burning (Epigastric Pain Syndrome, EPS), while patients with functional heartburn (normal pH and negative symptom association; FH) referred more frequently nausea, early satiety, postprandial fullness and bloating (Post-prandial Distress Syndrome, PDS). Moreover, in the same study we found that patients with abnormal-pH and overlapping EPS symptoms responded better to anti-secretive therapy (72%) than patients with hypersensitive esophagus (normal pH and positive symptom association) and FH (53% and 29%, respectively), although in our study the information about therapeutic response was retrospectively obtained. Overall, these results reinforce the role of acid not only in patients with gastroesophageal reflux disease but also in patients with EPS syndrome, in particular in case of epigastric burning, and suggest that in these patients antisecretory therapies should be considered as first choice more than in patients with PDS syndrome, where prokinetics seem to be more appropriate. At the same time therapies different from acid suppression (antidepressants? hypnotherapy?) should be considered in patients with FH in order to spare these patients from wasteful and protracted courses of years of acid suppression.