Introduction
Autonomic neuropathy affecting multiple organs is a common and severe complication of diabetes1. Neuropathy of the enteric nervous system and the regulatory autonomic nerve fibers can affect the entire gastrointestinal tract, causing mild to severe gastrointestinal symptoms2. The correlation between gastrointestinal symptoms and underlying pathophysiology is generally weak, so objective assessment is important to guide treatment3-5. Methods for direct evaluation of enteric neuropathy are not yet available in clinical practice. Hence, gastrointestinal transit times and contractile activity are used as proxies for enteric autonomic dysfunction6,7. Panenteric gastrointestinal assessment is considered essential, yet suitable methods are generally inaccessible, and diagnosing diabetic gastroenteropathy often causes significant challenges4,8. It is unknown whether measures of extraintestinal autonomic function can reflect diabetic gastroenteropathy and whether these measures could serve as supplementary diagnostic tools.
Aims & Methods
We aimed to assess 1) whether gastrointestinal symptoms are associated with motility measures and 2) whether gastrointestinal symptoms/motility measures are associated with extraintestinal autonomic markers. We included 81 persons with type 1 or type 2 diabetes (65% female, mean age 54) with gastrointestinal symptoms and either symptoms or signs of autonomic neuropathy. The Gastroparesis Cardinal Symptom Index (GCSI) and the Gastrointestinal Symptom Rating Scale (GSRS) were used to assess gastrointestinal symptoms. The wireless motility capsule assessed panenteric transit times and motility indices. Cardiovascular reflex tests performed with the VAGUS device and the cardiac vagal tone assessed with the eMotion Faros device estimated cardiovascular autonomic neuropathy, while the SUDOSCAN evaluated sudomotor function.
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 reflected 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 was 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.
Conclusion
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.
References
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