Effect of continuous positive airway pressure on blood pressure and the metabolic profile of women with obstructive sleep apnoea. A randomized-controlled trial

Objective: To assess the effect of continuous positive airway pressure (CPAP) on blood pressure (BP), glucose and lipid profile, in women with moderate-to-severe obstructive sleep apnoea (OSA). Methods: We conducted a multicentre, open-label, randomized controlled trial in 307 consecutive women diagnosed with moderate-to-severe OSA (apnoea-hypopnoea index ≥15) in 19 Spanish Sleep Units. Women were randomized to receive effective CPAP (n=151) or conservative treatment (n=156) for 3 months. Systolic (SBP) and diastolic office BP (DBP), fasting glucose, glycated haemoglobin (HbA1c), insulin resistance measured by the homeostasis model assessment (HOMA) and total, LDL and HDL cholesterol were assessed at baseline and at the end of the follow-up. Data were analysed on an intention-to-treat basis, with adjustment for baseline values, body mass index, age, and specific medical treatment. The results are expressed as adjusted intergroup changes (95%CI). Results: Women had a mean (SD) age 57.1 (10.1) years, body mass index 34.3 (7.0) Kg/m2, ESS 9.8 (4.4) and apnoea-hypopnoea index 38.6 (20.8). Compared to the control group, the CPAP group achieved a significantly greater improvement in DBP (mean difference -2.04 mmHg; 95%CI -4.02 to -0.05; p=0.045), and a non-significant improvement in SBP (mean difference -1.54 mmHg, 95%CI -4.58 to 1.51; p=0.32). No differences were shown in fasting glucose, HbA1c, HOMA, and cholesterol measures between groups. Conclusion: In women with moderate-to-severe OSA, 3 months of CPAP therapy improves BP, but not the glucose and lipid profile, compared to conservative treatment.