Autonomic Neuropathy Increases the Risk of Obstructive Sleep Apnea in Obese Diabetics

Abstract

Background: Nonobese diabetics with diabetic autonomic neuropathy (DAN) show an elevated prevalence of obstructive sleep apnea-hypopnea (OSAH). Objective: It was the aim of this study to assess if the presence of DAN could further increase the risk of developing OSAH in obese diabetics. Methods: Eighteen obese diabetic patients, 8 with DAN [age 57 ± 5 years, body mass index (BMI) 35 ± 4] and 10 without DAN (age 56 ± 8 years, BMI 37 ± 5), were recruited. Ten age-matched obese subjects were studied as controls (age 53 ± 12 years, BMI 34 ± 3). All subjects underwent a cardiorespiratory sleep study in the in-hospital sleep laboratory to obtain the apnea-hypopnea index (AHI) and oxygen desaturation indices. Results: Diabetics with DAN (Ob-DAN+) had a higher AHI than diabetics without DAN (Ob-DAN–) and controls, amounting to 39.5 ± 13 versus 15.8 ± 12 (p < 0.01) and 19.3 ± 21 (p < 0.05), respectively. A moderate-to-severe OSAH (AHI ≧15) occurred in all Ob-DAN+ and only in 4 Ob-DAN– and 4 control patients. Moreover, the indices reflecting the impairment of oxygen saturation (SaO₂) during sleep such as the mean lowest SaO₂ and sleep time with a SaO₂ <90% were more severely affected in Ob-DAN+ patients compared with the other groups and were associated with longer obstructive respiratory events. Conclusions: Apneas-hypopneas are more frequent and last longer in Ob-DAN+ than in other obese subjects, with or without diabetes.