The Role of Sleep-Disordered Breathing

In recent years, there have been numerous reports addressing the relationship between sleep-disordered breathing (SDB) and hypertension (HTN). This study investigated the relationship between SDB and BP after controlling for age, gross obesity, and notably, antihypertensive medications. Sixty-seven men and women between 30 and 60 years of age and between 0.90 to 1.5 times ideal body weight were studied. SDB was assessed over two nights of polysomnographic monitoring, and BP was measured over repeated vis¬ its to the hospital. The results indicate that respiratory disturbance index (BDI) independently predicts dia¬ stolic BP (DBP), accounting for 15% ofthe variance in DBP (p=0.02). In subjects with severe levels of SDB (RDI >30), RDI uniquely accounted for 36% of the variance in DBP (p=0.003). Interestingly, SDB was not independently related to systolic BP. The physiologic mechanisms responsible for these findings are cur¬ rently being explored. (CHEST 1996; 108:890-95)