To clarify the pathophysiology of functional dyspepsia (FD) and its relationship with the better understood syndrome of gastroparesis. Adult patients with chronic upper gastrointestinal symptoms were followed up prospectively for 48 weeks in multi-center registry studies. Patients were classified as having gastroparesis if gastric emptying was delayed; if not, they were labeled as having FD if they met Rome III criteria. Study analysis was conducted using analysis of covariance and regression models.
A total of 944 patients were enrolled during a 12-year period; 720 (76%) were in a gastroparesis group and 224 (24%) were in the FD group. Baseline clinical characteristics and severity of upper gastrointestinal symptoms were highly similar. The 48-week clinical outcome was also similar, but at this time, 42% of patients with an initial diagnosis of gastroparesis were reclassified as FD, based on gastric emptying results at this time point. Conversely, 37% of patients with FD were reclassified as having gastroparesis. Change in either direction was not associated with any difference in symptom severity changes. Fullthickness biopsies of the stomach showed loss of interstitial cells of Cajal and CD-206 macrophages in both groups, compared with obese controls.
It was concluded a year after initial classification, patients with FD and gastroparesis as seen in tertiary referral centers at least, are not distinguishable based on clinical and pathologic features, or based on assessment of gastric emptying. Gastric-emptying results are labile and do not reliably capture the pathophysiology of clinical symptoms in either condition. FD and gastroparesis are unified by characteristic pathologic features and should be considered as part of the same spectrum of truly “organic” gastric neuromuscular disorders.
Pasricha, P., Grover, M., Yates, K., et al for the National Institute of Diabetes and Digestive and Kidney Diseases/National Institute of Health Gastroparesis Clinical Research Consortium. “Functional Dyspepsia and Gastroparesis in Tertiary Care are Interchangeable Syndromes With Common Clinical and Pathologic Features.” Gastroenterology 2021; Vol. 160, pp. 2006-2017.