Osa in women: When does cpap increase blood pressure?

Background: There has been only one randomised clinical trial (RCT) on the effect of CPAP on women at three months. It showed that, overall, this treatment had no effect on blood pressure levels, even though some of the women presented increased blood pressure while under CPAP. Identifying this group of women could therefore be of clinical interest. Objective: To identify the risk factors for an increase (of at least 2 mmHg of BP) by analysing the CPAP arm of this RCT in those patients with inadequate and good adherence to CPAP. Methods: 151 women from the CPAP arm of the RCT were included. They all followed a complete sleep protocol that included CPAP pressure titration and office BP measures at baseline and one and three months after beginning CPAP treatment. Results: After exclusion, 137 women began the study. 69.3% showed good adherence to CPAP at 3 months and 77 patients (56.2%) increased their BP. In the overall group of women (independently of their adherence to CPAP), age, the presence of depression, baseline AHI and baseline SBP were associated with an increased BP (at least 2 mmHg) at 1 and 3 months. However, the BP increase was observed during the first month and tended to stabilize towards the third month. Conclusion: Greater age, the presence of depression and higher baseline AHI and SBP were independently associated with a clinical significant increase in BP after CPAP, regardless of their adherence. These changes in BP appeared mainly during the first month of treatment.