Aims Gastrointestinal disorders, including constipation and fecal incontinence, are common in type 2 diabetes mellitus (T2DM) and may derive from diabetic autonomic neuropathy, severe intestinal bacterial overgrowth, or a dysfunctional anorectal sphincter. The present study aims to characterize the correlation between these conditions.

Methods Patients with T2DM, prediabetes, and normal glucose tolerance (NGT) were included. The anorectal function was assessed with high-resolution anorectal manometry. Patients were screened for autonomic 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.

Results We included 59 participants (32 (54.2%) with T2DM, 9 (15.3%) with prediabetes, and 18 (30.5%) NGT). The presence of autonomic neuropathy, severe bacterial overgrowth, and symptoms of constipation and incontinence were comparable. HbA_1c 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 a long-standing diagnosis of T2DM, significantly higher values for maximum anorectal resting pressure (Δ=+27.81±7.84 mmHg, P=0.0015) and baseline pressure (Δ=20.50±9.74 mmHg, P=0.046) were found compared with NGT, but not with prediabetes.

Conclusions Long-standing T2DM increases anorectal sphincter activity, and constipation symptoms are associated with higher HbA_1c levels. The lack of an association of symptoms with autonomic neuropathy suggests glucotoxicity as the primary mechanism.

目的胃肠道疾病，包括便秘和大便失禁，在 2 型糖尿病 (T2DM) 中很常见，可能源于糖尿病自主神经病变、严重的肠道细菌过度生长或肛门直肠括约肌功能障碍。本研究旨在描述这些条件之间的相关性。

方法包括患有 T2DM、糖尿病前期和正常葡萄糖耐量 (NGT) 的患者。使用高分辨率肛门直肠测压法评估肛门直肠功能。通过测量嗅觉、汗液和勃起功能障碍以及心率变异性来筛查患者是否存在自主神经病变。使用经过验证的问卷评估便秘和大便失禁。呼吸测试用于评估严重的肠道细菌过度生长。

结果我们纳入了 59 名参与者（32 名 (54.2%) 患有 T2DM，9 名 (15.3%) 患有糖尿病前期，18 名 (30.5%) NGT）。自主神经病变、严重的细菌过度生长以及便秘和失禁症状的存在具有可比性。HbA _{1c与肛门直肠静息括约肌压力增加（} r =0.31，P =0.019）和便秘症状（r =0.30，P =0.031）相关。在长期诊断为 T2DM 的患者中，发现最大肛门直肠静息压 (Δ=+27.81±7.84 mmHg, P =0.0015) 和基线压力 (Δ=20.50±9.74 mmHg, P =0.046) 的值显着更高与 NGT，但与前驱糖尿病无关。

结论长期 T2DM 会增加肛门直肠括约肌的活动，便秘症状与较高的 HbA _1c水平相关。症状与自主神经病变之间缺乏关联表明葡萄糖毒性是主要机制。