Functional heartburn patients demonstrate traits of functional bowel disorder but lack a uniform increase of chemoreceptor sensitivity to acid.

Background: Functional heartburn (FH) patients have a profound impact on the response to anti-reflux therapy of the nonerosive reflux disease (NERD) group as compared to the response of the erosive esophagitis group. Thus far, there is paucity of information about their physiological and clinical characteristics that may separate them from the other NERD patients.

Aim: To compare physiological and clinical characteristics of patients with FH to their counterparts within the NERD group (NERD-positive [NERD+]).

Methods: Subjects with typical heartburn symptoms, at least twice a week, were evaluated by an upper endoscopy. Only those with normal esophageal mucosa were recruited into the study and underwent pH testing to assess esophageal acid exposure. The patients were divided into those with normal pH test (FH) and those with abnormal pH test (NERD+). The groups were compared for demographics, gastroesophageal reflux disease symptom characteristics, psychological profile, and reported quality of life. Additionally, the two patient groups were compared for stimulus response functions to acid, autonomic function response, and rate of Helicobacter pylori infection.

Results: Fifty-two patients included 30 with FH and the rest with NERD+. There was no statistical difference in demographics, frequency of hiatal hernia and H. pylori infection between the two groups. Patients with FH had a significantly longer history of heartburn and reported more episodes of chest pain than NERD+ patients (M--7.5 yr and M--once a week vs M--3.5 yr and M--once a month, respectively, p < 0.05). Patients with FH scored significantly higher in the somatization domain than patients with NERD+ (M--60 vs 52.5, p < 0.05), but had similar reported quality of life. Patients with NERD+ demonstrated a significantly shorter time to symptom perception and higher intensity rating (p < 0.05). Only patients with FH demonstrated a statistically significant increase in heart rate and skin conductance after acid perfusion, as compared to those with NERD+ (p < 0.05).

Conclusion: Patients with FH demonstrate increased reports of chest pain and somatization, an alteration in autonomic function but lack a uniform increase in chemoreceptor sensitivity to acid as compared to those with NERD+. This suggests that while FH patients harbor clinical traits of a functional bowel disorder, hypersensitivity to acid is not a general phenomenon.