Sleep disordered breathing and hypertension: does self-reported sleepiness modify the association?

STUDY OBJECTIVES: Epidemiologic studies that demonstrate increased risk of hypertension in persons with sleep disordered breathing indicate that only a minority of these persons report significant subjective sleepiness. Studies also suggest that presence of self-reported sleepiness may identify a subset of persons with sleep disordered breathing who are at greatest risk of cardiovascular sequelae, including hypertension. We explore whether self-reported sleepiness modifies the relationship between sleep disordered breathing and prevalent hypertension.

DESIGN: Cross-sectional.

SETTING: Multicenter study.

PARTICIPANTS: 6046 subjects from the Sleep Heart Health Study.

MEASUREMENTS: Polysomnography, systolic and diastolic blood pressure, antihypertensive medication use, questionnaire determined excessive sleepiness and Epworth Sleepiness Scale, and covariates.

RESULTS: The odds of hypertension at higher apnea hypopnea index categories were larger in participants identified as sleepy based on responses to a frequency of sleepiness question or the Epworth score. For example, for those with AHI > or =30 compared to AHI <1.5, the adjusted odds ratio for hypertension was 2.83 (1.33-6.04) among those reporting sleepiness > or =5 days per month, but only 1.22 (0.89-1.68) among those reporting less frequent daytime sleepiness. In adjusted logistic regression models, there was statistical evidence for effect modification by frequency of sleepiness (P = 0.033) of the association between apnea hypopnea index and hypertension. In adjusted models that included the Epworth score as a continuous variable, the interaction term fell slightly short of statistical significance (beta = 0.010, P = 0.07).

CONCLUSION: This study finds that the association of sleep disordered breathing with hypertension is stronger in individuals who report daytime sleepiness than in those who do not.