Relationship between obstructive sleep apnoea during rapid eye movement sleep and metabolic syndrome parameters in patients with type 2 diabetes mellitus

Purpose Sleep-disordered breathing (SDB) is associated with hypertension, poor glycemic control and dyslipidemia. Usually, apnoea events tend to be more prominent during rapid eye movement (REM) sleep than non-REM (NREM) sleep. We examined which SDB parameters are associated with blood pressure (BP), HbA1c and lipid profile in patients with type 2 diabetes (T2D). Methods A total of 185 patients with T2D who underwent polysomnography were analysed. Exclusion criteria were: the presence of pulmonary diseases, central sleep apnoea, treated SDB, or REM sleep < 30 min. To predict BP, HbA1c, and lipid profiles, we performed multiple linear regression analyses adjusted for known risk factors. Subsequently, we performed multivariable logistic regression analyses. Results Patient characteristics (mean ± standard deviation/median) were as follows: age 58.0 ± 11.8 years, body mass index 26.0 kg/m2 (24.1–28.9 kg/m2 ), systolic BP 134 ± 19 mmHg, mean BP 98 ± 14 mmHg, HbA1c 7.4% (6.8–8.4%), triglyceride 143 mg/dL (97–195 mg/dL), non-high density lipoprotein (non-HDL) cholesterol 143 mg/dL (120–163 mg/dL), REM-apnoea–hypopnea index (AHI) 35.1/h (21.1–53.1/h). The analyses revealed that REM-AHI was independently associated with systolic and mean BP, whereas NREM-AHI was not. A statistically significant association was not observed between REM-AHI and HbA1c or lipid profile. Conclusion In patients with T2D, REM-AHI was associated with systolic and mean BP. The alteration of BP, associated with SDB during REM sleep, may be an important pathophysiological link between SDB and cardiovascular diseases.