The Overlap Subgroup of Functional Dyspepsia Exhibits More Severely Impaired Gastric and Autonomic Functions

Goals: A combination of multiple tests was introduced to noninvasively investigate the differences in pathophysiologies among functional dyspepsia (FD) subgroups, including postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and overlap. Background: It has not been extensively evaluated whether different pathophysiologies are involved in FD subgroups. Study: This multicenter study included 364 FD patients fulfilling Rome IV criteria and 47 healthy controls. A combined noninvasive gastric and autonomic function test was performed: The electrogastrogram and electrocardiogram were recorded simultaneously in the fasting state and after a drink test. Symptoms after drinking were recorded using visual analog scale. Results: (1) Compared with HC, FD patients showed a decreased maximum tolerable volume (MTV) (P<0.01) and percentage of normal gastric slow waves [normal gastric slow waves (%NSW)] (P<0.01), and increased postdrinking symptoms, anxiety (P<0.01), and depression (P<0.01). The drink reduced %NSW in both FD patients and HC; however, the effect was more potent in patients. (2) The PDS and overlap groups displayed a reduced MTV (P<0.05). The overlap group exhibited a higher symptom score at 30 minutes after drinking, and higher anxiety and depression scores, and a higher sympathovagal ratio than the EPS (P<0.05 for all) and PDS (P<0.01 for all). (3) In the PDS subgroup, the MTV, postprandial sympathovagal ratio, and depression were associated with the overall dyspepsia symptom scale (DSS, P=0.034, 0.021, 0.043, respectively). No significant associations were found in the other 2 subgroups. Conclusions: The combination of multiple tests can detect pathophysiological abnormities in FD patients. Overall, patients with overlap symptoms display more severe pathophysiologies.