Effect of continuous positive airway pressure on blood pressure in normotensive individuals with obstructive sleep apnoea: a randomised trial

The use of continuous positive airway pressure prevents an increase in blood pressure in normotensive subjects with a dipping blood pressure pattern and severe obstructive sleep apnoea. Background : The effects of continuous positive airway pressure (CPAP) on blood pressure (BP) in normotensive subjects, particularly among those with a dipping BP pattern, remain uncertain, raising questions about its indication for this group of patients. We assessed the impact of CPAP on BP in normotensive subjects with a dipping BP pattern and severe obstructive sleep apnoea (OSA). Methods : Randomised, parallel, prospective, controlled trial. Inclusion criteria were an apnoea-hypopnea index ≥30 events/hour, mean 24-hour BP <130/80 mmHg, and daytime-to-nighttime BP reduction ≥10%. Patients were randomly assigned to receive either CPAP treatment or usual care for 12 weeks. The primary outcome was the change in ambulatory BP monitoring (ABPM) parameters from baseline to the three-month follow-up. Results : The 60 patients who completed the follow-up had a mean age of 52.2 years ( sd 10.8), and 40 of them (66.7%) were male. The intention-to-treat analysis showed no significant changes with CPAP, whereas the usual care group experienced increases in ABPM parameters. This resulted in a mean difference of −3.4 mmHg (95% CI: −6.124 to −0.676; p=0.015) in nighttime diastolic BP between the groups. The per-protocol analysis indicated significant differences between the CPAP and usual care groups for all primary endpoints, except for daytime systolic BP. For nighttime systolic BP, the difference was −6.052 mmHg (95% CI: −10.895 to −1.208; p=0.016). Conclusion : These findings suggest a protective effect of CPAP, highlighting the importance of CPAP prescription for this population to control potential increases in blood pressure and possibly prevent the onset of hypertension.