Sleep quality and blood pressure dipping in obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is associated with poor sleep qua lity and a high incidence of nondipping. The aim of this study was to deter mine the association of sleep quality and nocturnal blood pressure (BP) dip ping in an OSA population. Methods: A total of 44 untreated subjects with mild to severe OSA underwent overnight-attended polysomnography and 24-h ambulatory BP monitoring. Subj ects were off antihypertensive medication. The percentage of slow wave slee p, percentage of time awake after sleep onset during the sleep period, slee p efficiency, and arousal index were chosen as measurements of sleep qualit y. Dipping was evaluated using the change in systolic BP, diastolic BP, and mean arterial pressure. Patients were classified as dippers and nondippers based on a nocturnal drop in mean arterial pressure > 10%. Differences bet ween groups were evaluated by independent sample t tests. Pearson correlati on and linear regression were used to evaluate the association of sleep qua lity and dipping. Results: There were no differences between dippers and nondippers with rega rd to body mass index, age, or respiratory disturbance index. A total of 84 % were nondippers. No difference was found between dippers and nondippers i n sleep quality. None of the sleep quality measures correlated with the mea surements of dipping. In multiple regression analyses, the percentage of sl ow wave sleep and arousal index each independently predicted only a small p ercentage of the variance (approximately 10%) of nocturnal DBP dipping. Conclusions: The prevalence of nondipping was very high in a population of untreated patients with mild to severe OSA. Nonetheless, sleep quality did not appear to be related to BP dipping. (C) 2001 American Journal of Hypert ension, Ltd.