Digestive, anorectal, and urogenital functions in patients with type 2 diabetes mellitus, impaired glucose tolerance and normal glucose tolerance: Association with autonomic neuropathy.

Abstract

Gastrointestinal disorders including constipation and fecal incontinence are common in type 2 diabetes and may derive from diabetic autonomous neuropathy, severe intestinal bacterial overgrowth, or a dysfunctional anorectal sphincter. The present study aims to characterize the correlation between these conditions. Patients with type 2 diabetes, prediabetes and normal glucose tolerance were included. Anorectal function was assessed with high-resolution anorectal manometry. Patients were screened for autonomous neuropathy by measuring olfactory, sweat, and erectile dysfunction as well as heart rate variability. Constipation and fecal (in-)continence were evaluated using validated questionnaires. Breath tests were used to assess severe intestinal bacterial overgrowth. We included 59 participants (32 (54.2%) type 2 diabetes, 9 (15.3%) prediabetes and 18 (30.5%) normal glucose tolerance). Presence of autonomous neuropathy, severe bacterial overgrowth and symptoms of constipation and incontinence was comparable. HbA1c was correlated with an increased anorectal resting sphincter pressure (r = 0.31, P = 0.019) and constipation symptoms (r = 0.30, P = 0.031). In patients with long- standing diagnosis of type 2 diabetes significantly higher values for maximum anorectal resting pressure (∆ = +27.81 ± 7.84 mmHg, P = 0.0015) and baseline pressure (∆ = 20.50 ± 9.74 mmHg, P = 0.046) were found compared with normal glucose tolerance, but not with prediabetes. Long-standing type 2 diabetes increases anorectal sphincter activity, and constipation symptoms are associated with higher HbA1c levels. The lack of an association of symptoms with autonomous neuropathy suggests glucotoxicity as the primary mechanism.