Abstract
This study aimed to examine the association between obstructive sleep apnea (OSA) and morning blood pressure surge in never-treated patients with essential hypertension. This prospective study included a total of 58 patients (mean age, 51.7 years; 55.2% men) with never-treated essential hypertension. The patients were divided into non-OSA (n=23, 49.3±12.7 years) and OSA (n=35, 53.2±9.8 years) groups. The OSA group was defined as having an apnea-hypopnea index level >5 as measured by the Watch-PAT 200. The authors collected 24-hour ambulatory BP, plasma aldosterone concentration, and plasma renin activity data from all of the patients. The measured sleep-trough morning systolic blood pressure (SBP) increases were higher in the OSA group than in the non-OSA group (28.7±11.8 mm Hg vs 19.6±12.8 mm Hg, P=.008). The sleep-trough morning SBP increase was inversely correlated with the lowest oxygen saturation (r=-0.272, P=.039). OSA known to be associated with increased daytime and nocturnal sympathetic activity was associated with significantly higher sleep-trough morning SBP levels in this study.