OBSTRUCTIVE SLEEP APNEA IN RELATION TO BEAT-TO-BEAT, READING-TO-READING, AND DAY-TO-DAY BLOOD PRESSURE VARIABILITY

Abstract

Objective: We investigated blood pressure (BP) variability as assessed by beat-to-beat, reading-to-reading and day-to-day BP variability indices in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Design and method: In 786 hospitalized hypertensives (mean age, 53.2 years; 42.2% women), we performed 10-minute beat-to-beat (n=705), 24-hour ambulatory (n=779), and 7-day home BP (n=445) measurements and the full overnight polysomnography. Mild, moderate and severe OSAHS were defined as an apnea-hypopnea index of 5-14, 15-29, and >= 30 events per hour, respectively. BP variability indices including variability independent of the mean (VIM), average real variability (ARV), and maximum–minimum difference (MMD), were compared across the OSAHS severity groups. Results: In univariate analysis, beat-to-beat systolic VIM and MMD, reading-to-reading asleep systolic and diastolic ARV and MMD increased from patients without OSAHS, to patients with mild, moderate and severe OSAHS. This increasing trend for beat-to-beat systolic VIM and MMD remained statistically significant after adjustment for confounders (P <=0.047). There was significant (P <=0.039) interaction of the presence and severity of OSAHS with age and body mass index in relation to the beat-to-beat systolic VIM and MMD and with the presence of diabetes mellitus in relation to asleep systolic ARV. The association was stronger in younger (age < 50 years) and obese (body mass index >= 28 kg/m2) and diabetic patients. None of the day-to-day BP variability indices reached statistical significance (P>=0.16). Conclusions: BP variability, in terms of beat-to-beat recordings, were higher with the more severe OSAHS, especially in younger and obese and diabetic patients.