Improvement of glycemic control by treatment for insomnia with suvorexant in type 2 diabetes mellitus

Introduction: Acute and chronic insomnia can exacerbate type 2 diabetes mellitus (T2DM). We investigated suvorexant (an anti-insomnia drug that targets the orexin system) effects on sleep architecture and glucose metabolism in T2DM patients with insomnia. Materials and methods: This 7 day open-label, single-arm, intervention trial included 18 subjects with T2DM and insomnia. After 1 day acclimatization, daily glucose levels, sleep architecture, and autonomic nervous function were evaluated by continuous glucose monitoring (CGM), single-channel electroencephalography, and accelerometry, respectively. Results: Suvorexant treatment for 3 days significantly increased total sleep time and sleep efficiency, with partial suppression of sympathetic nerve activity. CGM-measured 24 h mean glucose level decreased significantly from 157.7 +/- 22.9 to 152.3 +/- 17.8 mg/dL, especially in the early glucose surge after the midnight nadir (from 28.3 +/- 15.0 to 18.2 +/- 9.9 mg/dL), and until supper with a significant improvement in homeostasis model assessment of insulin resistance from 4.0 +/- 2.8 to 2.9 +/- 1.6, respectively. Conclusions: Suvorexant treatment for insomnia of subjects with T2DM significantly improved CGM-measured daily glycemic control, which was associated with changes in sympathomimetic tone and/or improved insulin sensitivity. The amelioration of insomnia may therefore be a target for improving glycemic control in T2DM patients with insomnia.