Diabetic gastroenteropathy: Associations between gastrointestinal symptoms, motility, and extraintestinal autonomic measures

Background: Diabetic gastroenteropathy can cause significant diagnostic challenges. Still, it remains unknown if measures of extraintestinal autonomic function reflect diabetic gastroenteropathy. We aimed to assess the associations between (1) gastrointestinal symptoms and motility measures and (2) gastrointestinal symptoms/motility measures and extraintestinal autonomic markers. Methods: We included 81 persons with type 1 or type 2 diabetes (65% female, mean age 54) with gastrointestinal symptoms and autonomic neuropathy. The Gastroparesis Cardinal Symptom Index (GCSI) and the Gastrointestinal Symptom Rating Scale (GSRS) assessed gastrointestinal symptoms. The wireless motility capsule (Smartpill™) assessed panenteric transit times and motility indices. Cardiovascular reflex tests (VAGUS™) and cardiac vagal tone (eMotion Faros) estimated cardiovascular autonomic neuropathy, while the SUDOSCAN™ evaluated sudomotor function. Key Results: Proximal gastrointestinal symptoms were positively associated with the gastric motility index (GCSI: 1.18 (1.04–1.35), p = 0.01; GSRS: 1.15 (1.03–1.29), p = 0.02; median ratio (95% CI)), while only satiety correlated with gastric emptying time (1.24 (1.03–1.49), p = 0.02). Diarrhea was associated with decreased small bowel transit time (0.93 (0.89–0.98), p = 0.005), while constipation were associated with prolonged colonic transit time (1.16 (1.03–1.31), p = 0.02). Gastrointestinal symptoms increased with the degree of abnormal cardiovascular reflex tests (GCSI: 0.67 (0.16–1.19), p = 0.03; GSRS: 0.87 (0.30–1.45), p = 0.01; mean difference (95% CI)) but not with motility measures. Cardiac vagal tone and sudomotor function were not associated with gastrointestinal markers. Conclusions & Inferences: Gastrointestinal and extraintestinal autonomic measures were not associated. However, proximal gastrointestinal symptoms were associated with the gastric motility index and cardiovascular reflex tests. Hence, the latter may contribute to evaluating whether proximal gastrointestinal symptoms are autonomically derived.