Effects of CPAP therapy on visceral fat thickness, carotid intima-media thickness and adipokines in patients with obstructive sleep apnoea.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnoea (OSA) is associated with an increased prevalence of metabolic syndrome. This study explores the effects of continuous positive airway pressure (CPAP) for patients with OSA on visceral and mesenteric fat thickness, carotid intima-media thickness (IMT) and adipokines.

METHODS: A randomized controlled study was conducted at a teaching hospital on 90 patients newly diagnosed with OSA to receive either therapeutic CPAP or subtherapeutic CPAP for 3 months. Visceral fat thickness and carotid IMT were measured with B-mode ultrasound; adipokine levels were assessed at baseline and 3 months.

RESULTS: Altogether, 45 patients received therapeutic CPAP and 45 received subtherapeutic CPAP without significant differences in age 50.3 (10.1) versus 48.7 (9.0) years, BMI 28.2 (3.9) versus 28.2 (4.5) kg/m2 , Epworth Sleepiness Scale (ESS) 12.4 (5.9) versus 11.3 (4.7), apnoea-hypopnoea index (AHI) 30.6 (21.4) versus 35.2 (25.5) /h, minimum SaO2 79.6 (10.8) versus 76.7 (12.4) % and existing co-morbidities. CPAP usage was therapeutic 4.2 (2.1) versus subtherapeutic 4.1 (2.0) h/night over 3 months. Adiponectin and irisin levels changed significantly following therapeutic CPAP for 3 months versus subtherapeutic CPAP (-1.6 vs 7.3, P = 0.042; 0.1 vs -0.1, P = 0.028 respectively) while only serum level of monocyte chemotactic protein 1 (MCP-1) at baseline was positively correlated with AHI (r = 0.278). No significant changes were observed in other adipokines, visceral fat thickness and IMT.

CONCLUSION: Short-term therapeutic CPAP versus subtherapeutic CPAP does not significantly reduce visceral fat thickness and IMT, although it reduces adiponectin and increases irisin.