Obstructive Sleep Apnoea and Vascular Disease in Patients with Type 2 Diabetes

Abstract

Obstructive sleep apnoea (OSA) is common and is associated with many vascular risk factors, such as hypertension, insulin resistance, albuminuria, dyslipidaemia, increased inflammation and endothelial dysfunction. Epidemiological studies have shown that OSA is associated with increased cardiovascular disease (CVD) and that continuous positive airway pressure (CPAP) might reduce CVD events in patients with OSA. In addition, OSA has also been shown to be associated with albuminuria, chronic kidney disease, a wide range of ocular diseases and peripheral neuropathy. Considering that CVD and microvascular complications are major contributors to the morbidity, mortality and the economic burden of diabetes and that OSA is common in patients with type 2 diabetes (T2D), it is important to understand the role of OSA in the development and/or progression of vascular disease in patients with T2D and to explore the impact of CPAP on diabetes-related vascular outcomes. The purpose of this article is to review the evidence for the relationship and impact of OSA on vascular disease and vascular risk factors particularly in patients with T2D. KeywordsType 2 diabetes, obstructive sleep apnoea, vascular disease, vascular risk Diabetes-related macro-and microvascular complications contribute significantly to the increased morbidity, mortality, worsened quality of life and social and financial burden observed in patients with diabetes. [1][2][3][4][5] Hence, reducing the development and/or the progression of these complications is one of the main aims of treatment in patients with diabetes.Over the last 2 decades, strategies resulting in the improvements of glycaemic control, blood pressure (BP) and lipids and the use of renin angiotensin aldosterone inhibitors, resulted in reductions in cardiovascular disease (CVD) in patients with diabetes, but there was little impact on diabetic microvascular complications. 6 Nonetheless, both CVD and microvascular complications remain common and a better understanding of the pathogenesis of these complications is needed in order to identify new treatment strategies.Obstructive sleep apnoea (OSA) is common in patients with type 2 diabetes (T2D) (up to 86 % prevalence), which is not surprising considering that increasing age and obesity are common risk factors to both conditions. 7,8 OSA is characterised by upper airway instability during sleep that results in recurrent upper airway obstruction resulting in either complete or partial cessation of airflow (i.e. apnoea and hypopnoea, respectively). 9The recurrent obstructions of the upper airway usually result in recurrent oxygen desaturations/re-saturations, cyclical changes in intrathoracic pressure (as the patient attempts to breath against a blocked airway) and recurrent micro arousals that cause sleep fragmentation and reduction in slow wave and rapid eye movement (REM) sleep and result in termination of the apnoea/hypopnoea episodes. 9Several large epidemiological studies and randomised controlled trials (RCTs) have shown that OSA was ...

Obstructive sleep apnoea in diabetes: Does it matter?

“…OSA has been linked to worse glycaemic measures (such as HbA1c, fasting plasma glucose or glucose variability) following adjustment for a wide range of confounders in several cross-sectional studies. 2,4,53 However, though biologically plausible, causality between OSA and worse glycaemic control has not been proven as yet due to the lack of longitudinal studies and the conflicting results of clinical trials. The impact of OSA on HbA1c ranged between 0.7% and 3.69%; this variation between studies is likely to be due to methodological differences and variability in OSA severity between studies.…”

“…The impact of OSA on HbA1c ranged between 0.7% and 3.69%; this variation between studies is likely to be due to methodological differences and variability in OSA severity between studies. 2,4,53…”

“…OSA shares many of its molecular consequences with hyperglycaemia which can lead to microvascular complications in patients with T2D (Table 1). OSA can result in increased oxidative stress and nitrosative stress, poly (ADP-ribose) polymerase (PARP) activation, increased advanced glycation end-products (AGE), protein kinase C (PKC) activation, inflammation and endothelial dysfunction in patients with and without T2D, 2,53,74,75 all of which are involved in the pathogenesis of microvascular complications in T2D. 76…”

“…The impact of OSA on HbA1c ranged between 0.7% and 3.69%; this variation between studies is likely to be due to methodological differences and variability in OSA severity between studies. 2,4,53 Overall, uncontrolled studies of short duration (⩾4 months) showed that CPAP improved glycaemic variability, postprandial glucose levels and HbA1c in patients with T2D, but RCTs did not overall show such benefits. 2,4,53 In a small RCT of 42 men with T2D and OSA who were randomised to CPAP versus sham CPAP, 3 months of treatment did not show any impact of CPAP on HbA1c but CPAP compliance was poor, preventing definitive conclusions.…”

Novel therapies in type 2 diabetes: insulin resistance

“…OSA is very common in patients with T2D and is associated with IR and worse glycaemic control . Several meta‐analyses have shown that OSA treatment (continuous positive airway pressure; CPAP) improves IR in patients with and without T2D …”