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

REM sleep obstructive sleep apnoea

Obstructive sleep apnoea (OSA) can occur in both rapid eye movement (REM) and non-REM sleep or be limited to REM sleep, when the upper airway is most prone to collapse due to REM sleep atonia. Respiratory events are usually longer and more desaturating in REM than in NREM sleep. The prevalence of REM OSA is higher in women than in men and REM OSA usually occurs in the context of mild-moderate OSA based on the apnoea-hypopnoea index calculated for the entire sleep study. Studies have highlighted some detrimental consequences of REM OSA; for example, its frequent association with systemic hypertension and a degree of excessive daytime sleepiness similar to that found in nonsleep-stage-dependent OSA. Moreover, REM OSA could increase cardiometabolic risk. Continuous positive airway pressure (CPAP) treatment aimed at preventing REM OSA should be longer than the 4 h usually considered as good compliance, since REM sleep occurs mostly during the second half of the night. Unfortunately, patients with REM OSA show poor adherence to CPAP. Alternative non-CPAP treatments might be a good choice for REM OSA, but data are lacking. This review summarises the available data on REM OSA and critically examines the weaknesses and strengths of existing literature.

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

Obstructive sleep apnoea (OSA) is associated with cardiovascular and metabolic comorbidities, including hypertension, dyslipidaemia, insulin resistance and atherosclerosis. Strong evidence suggests that OSA is associated with an altered lipid profile including elevated levels of triglyceride-rich lipoproteins and decreased levels of high-density lipoprotein (HDL). Intermittent hypoxia; sleep fragmentation; and consequential surges in the sympathetic activity, enhanced oxidative stress and systemic inflammation are the postulated mechanisms leading to metabolic alterations in OSA. Although the exact mechanisms of OSA-associated dyslipidaemia have not been fully elucidated, three main points have been found to be impaired: activated lipolysis in the adipose tissue, decreased lipid clearance from the circulation and accelerated de novo lipid synthesis. This is further complicated by the oxidisation of atherogenic lipoproteins, adipose tissue dysfunction, hormonal changes, and the reduced function of HDL particles in OSA. In this comprehensive review, we summarise and critically evaluate the current evidence about the possible mechanisms involved in OSA-associated dyslipidaemia.

Association of apnea-hypopnea index during rapid eye movement sleep with insulin resistance in patients with suspected obstructive sleep apnea: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is associated with insulin resistance. However, the association between special stages of OSA [rapid eye movement (REM) sleep] and insulin resistance is not clear. This study was designed to assess the association of the frequency of respiratory events during REM sleep with insulin resistance in adults with suspected OSA.

Methods

In this cross-sectional study, 4,062 adult participants with suspected OSA who underwent polysomnography in our sleep center between 2009 and 2016 were screened. Polysomnographic variables, biochemical indicators, and physical measurements were collected. Logistic regression analyses were conducted to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for insulin resistance as assessed by the presence of hyperinsulinemia, the homeostasis model assessment of insulin resistance (HOMA-IR) index, the fasting insulin resistance index (FIRI), and Bennett’s insulin sensitivity index (ISI).

Results

The final analyses included 2,899 adults with suspected OSA. Multivariate adjustments, including the apnea-hypopnea index (AHI) during non-REM sleep (AHI_NREM), were performed. The AHI during REM sleep (AHI_REM) was found to be independently associated with insulin resistance across increasing AHI_REM quartiles. For hyperinsulinemia the ORs (95% CIs) followed the order of 1.340 (1.022, 1.757), 1.210 (0.882, 1.660), and 1.632 (1.103, 2.416). For abnormal HOMA-IR, ORs (95% CIs) were 1.287 (0.998, 1.661), 1.263 (0.933, 1.711), and 1.556 (1.056, 2.293). For abnormal FIRI, ORs (95% CIs) were 1.386 (1.048, 1.835), 1.317 (0.954, 1.818), and 1.888 (1.269, 2.807). For abnormal Bennett’s ISI, ORs (95% CIs) were 1.297 (1.003, 1.678), 1.287 (0.949, 1.747), and 1.663 (1.127, 2.452). All linear trends were statistically significant (P<0.01). Additionally, the results showed that REM sleep duration was independently associated with hyperinsulinemia (OR =0.777, 95% CI: 0.615–0.982; P<0.05).

Conclusions

AHI_REM was independently associated with hyperinsulinemia and an abnormal HOMA-IR, FIRI, and Bennett’s ISI in adults with suspected OSA. Additionally, REM sleep duration was independently associated with hyperinsulinemia.