The Relationship of Sleepiness and Blood Pressure to Respiratory Variables in Obstructive Sleep Apnea

¹ From the Cleveland Clinic Foundation

As a follow-up to a previous assessment of complications of sleep-disturbed breathing in 265 patients, we have reevaluated measures of sleepiness and hypertension in patients with obstructive sleep apnea (OSA) (n=518), central sleep apnea (n=50), and subclinical sleep-disordered breathing (SDB) (n=107). Both subjective and objective (multiple sleep latency test [MSLT]) measures indicated that OSA patients were sleepier than those with subclinical SDB. The OSA patients weighed significantly more than the patients with central sleep apnea or subclinical SDB. They had a higher proportion of men, described more habitual sleepiness, and had a higher likelihood of feeling unrefreshed in the morning compared with the group with subclinical SDB. Among the OSA patients, there was a significant correlation between subjective and objective assessment of sleepiness, but this relationship was quantitatively very small. A forward stepwise regression analysis revealed that weight, and to a lesser degree waking time after sleep onset, could account for 65.5% of the variance in subjective sleepiness. Seventy-five percent of the variance of the mean sleep latency in the MSLT could be accounted for by the mean minimum arterial oxygen saturation in non-REM sleep and the nocturnal sleep latency. Diastolic BP was significantly higher in OSA patients compared with the patients with central sleep apnea and subclinical SDB. When covarying for weight, age, and gender, this effect lost significance. Among OSA patients taken by themselves, 98.3% of the variance in diastolic blood pressure could be accounted for by the mean minimum arterial oxygen saturation in non-REM sleep, with very small additional contributions of apnea/hypopnea index, weight, and age. In summary, among patients across a spectrum of SDB, differences in diastolic BP were primarily associated with weight, age, and gender. Among OSA patients, perhaps because of a more limited variance in weight, diastolic BP was associated with measures of SDB.

Key Words: hypertension • sleep • sleep apnea • sleep-disordered breathing • sleepiness

Submitted on December 20, 1994
Accepted on May 3, 1995

This article has been cited by other articles:

				M. M. Ohayon Prevalence and Correlates of Nonrestorative Sleep Complaints Arch Intern Med, January 10, 2005; 165(1): 35 - 41. [Abstract] [Full Text] [PDF]

				G V Robinson, J R Stradling, and R J O Davies Sleep {middle dot} 6: Obstructive sleep apnoea/hypopnoea syndrome and hypertension Thorax, December 1, 2004; 59(12): 1089 - 1094. [Abstract] [Full Text] [PDF]

				Z. Pelin, D. Karadeniz, L. Ozturk, E. Gozukirmizi, and H. Kaynak The role of mean inspiratory effort on daytime sleepiness Eur. Respir. J., April 1, 2003; 21(4): 688 - 694. [Abstract] [Full Text] [PDF]

				R. A. Dart, J. R. Gregoire, D. D. Gutterman, and S. H. Woolf The Association of Hypertension and Secondary Cardiovascular Disease With Sleep-Disordered Breathing Chest, January 1, 2003; 123(1): 244 - 260. [Abstract] [Full Text] [PDF]

				C Sjostrom, E Lindberg, A Elmasry, A Hagg, K Svardsudd, and C Janson Prevalence of sleep apnoea and snoring in hypertensive men: a population based study Thorax, July 1, 2002; 57(7): 602 - 607. [Abstract] [Full Text] [PDF]

				N. M. PUNJABI, D. J. O'HEARN, D. N. NEUBAUER, F. J. NIETO, A. R. SCHWARTZ, P. L. SMITH, and K. BANDEEN-ROCHE Modeling Hypersomnolence in Sleep-disordered Breathing . A Novel Approach Using Survival Analysis Am. J. Respir. Crit. Care Med., June 1, 1999; 159(6): 1703 - 1709. [Abstract] [Full Text]

				J. Wright, R. Johns, I. Watt, A. Melville, and T. Sheldon Health effects of obstructive sleep apnoea and the effectiveness of continuous positive airways pressure: a systematic review of the research evidence BMJ, March 22, 1997; 314(7084): 851 - 851. [Abstract] [Full Text]