Hypertension and blood pressure variability in patients with obstructive sleep apnea

Abstract

Comment on original article, Cheng et al.'s "Obstructive Sleep Apnea in Relation to .Obstructive sleep apnea (OSA) is associated with hypertension and cardiovascular disease [2,3]. In 786 hospitalized patients with hypertension, Cheng et al. performed 10-min awake beat-to-beat blood pressure (BP) monitoring (n = 705), 24-h ambulatory BP monitoring (ABPM) (n = 779), 7-day home BP monitoring (n = 445) and the full overnight polysomnography. Variability independent of the mean (VIM), average real variability (ARV), and maximum-minimum difference (MMD) were used as indices of BP variability. In univariate analysis, VIM and MMD in awake beat-to-beat systolic BP, and sleep systolic and diastolic ARV and MMD increased from patients without obstructive sleep apnea syndrome (OSAS), to patients with mild, moderate and severe OSAS. After adjustment for confounders, this increasing trend for VIM and MMD in awake beat-to-beat systolic BP remained statistically significant. This study reported clinically significant results. However, it has several limitations.The first limitation is that the authors measured only awake beat-to-beat BP during daytime and not sleep beatto-beat BP during nighttime. If sleep beat-to-beat BP had been available, the BP variability between awake and sleep beat-to-beat BP could be compared, which may become additional important findings. For example, it is clinically important whether 10-min awake beat-to-beat BP variability can predict severity of sleep beat-to-beat BP variability.