CPAP withdrawal-induced OSA ups free fatty acids, glucose, cortisol during sleep
Cessation of continuous positive airway pressure (CPAP) elicits the occurrence of obstructive sleep apnoea (OSA) associated with sympathetic and adrenocortical activation thereby increasing plasma free fatty acids (FFAs) and glucose during sleep, a recent study has found. Repeated exposure to these metabolic changes may lead to diabetes and cardiovascular disease.
A randomized crossover trial of CPAP vs CPAP withdrawal, including 31 patients with moderate to severe OSA acclimated to CPAP, was conducted to assess the impact of OSA on frequently sampled nocturnal metabolic markers, such as plasma FFAs, glucose, insulin, triglycerides, cortisol and lactate, as well as glucose production, oral glucose tolerance, blood pressure (BP), endothelial function, cholesterol and high-sensitivity C-reactive protein (hsCRP).
Patients underwent polysomnography while sleeping with therapeutic CPAP, or after CPAP withdrawal, in random order. Researchers tested venous blood at approximately 20-minute intervals on both nights. Moreover, the assessed glucose kinetics with an infusion of 6,6-[2H2]glucose on 11 patients.
CPAP withdrawal triggered the recurrence of OSA associated with hypoxaemia, sleep disruption and heart rate elevation, as well as dynamically increased nocturnal FFA (p=0.007), glucose (p=0.028) and cortisol (p=0.037), in proportion to respiratory event frequency, heart rate elevation or sleep fragmentation. Diabetes predisposed to glucose elevation.
In addition, CPAP withdrawal led to higher systolic BP (p=0.017) and augmentation index (p=0.008). However, it did not affect insulin, triglycerides, glucose production, oral glucose tolerance, cholesterol or hsCRP.
“OSA is associated with diabetes and cardiovascular disease. This association may be related to metabolic changes that transpire during sleep in OSA,” researchers said.