Obstructive sleep apnea during REM sleep and hypertension. results of the Wisconsin Sleep Cohort

Abstract

Rationale: Obstructive sleep apnea (OSA) is associated with hypertension.

Objectives: We aimed to quantify the independent association of OSA during REM sleep with prevalent and incident hypertension.

Methods: We included adults enrolled in the longitudinal community-based Wisconsin Sleep Cohort Study with at least 30 minutes of REM sleep obtained from overnight in-laboratory polysomnography. Studies were repeated at 4-year intervals to quantify OSA. Repeated measures logistic regression models were fitted to explore the association between REM sleep OSA and prevalent hypertension in the entire cohort (n = 4,385 sleep studies on 1,451 individuals) and additionally in a subset with ambulatory blood pressure data (n = 1,085 sleep studies on 742 individuals). Conditional logistic regression models were fitted to longitudinally explore the association between REM OSA and development of hypertension. All models controlled for OSA events during non-REM sleep, either by statistical adjustment or by stratification.

Measurements and main results: Fully adjusted models demonstrated significant dose-relationships between REM apnea-hypopnea index (AHI) and prevalent hypertension. The higher relative odds of prevalent hypertension were most evident with REM AHI greater than or equal to 15. In individuals with non-REM AHI less than or equal to 5, a twofold increase in REM AHI was associated with 24% higher odds of hypertension (odds ratio, 1.24; 95% confidence interval, 1.08-1.41). Longitudinal analysis revealed a significant association between REM AHI categories and the development of hypertension (P trend = 0.017). Non-REM AHI was not a significant predictor of hypertension in any of the models.

Conclusions: Our findings indicate that REM OSA is cross-sectionally and longitudinally associated with hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of REM sleep untreated.

Keywords: REM-related sleep apnea; hypertension; obstructive sleep apnea; rapid eye movement; sleep-disordered breathing.

Figure 1.

Odds ratios and 95% confidence intervals for REM apnea–hypopnea index (AHI) severity categories and prevalent hypertension. Repeated measures logistic regression models fitted to examine cross-sectional associations between obstructive sleep apnea during REM sleep based on REM AHI categories and prevalent hypertension. (A) Association for the entire cohort (n = 4,385 polysomnograms on 1,451 individuals). (B) Subsample with non-REM AHI less than or equal to 5 (n = 2,953 polysomnograms on 1,216 individuals). (C) Association between prevalent hypertension in the subset with available ambulatory blood pressure monitoring data (n = 1,085 polysomnograms on 742 individuals). (D) Subset of subjects with available ambulatory blood pressure monitoring data and non-REM AHI less than or equal to 5 (n = 779 polysomnograms on 572 individuals). Increasing REM AHI categories were associated with increased risk of hypertension in all models and it reached statistical significance in the entire cohort (A) and in the subsample of subjects who had ambulatory blood pressure monitoring data limited to non-REM AHI less than or equal to 5 (D). All estimates are adjusted for age, sex, race, body mass index, waist-to-hip ratio, smoking, alcohol, and log₂(non-REM AHI + 1). In A, the P value for log₂(non-REM AHI + 1) was 0.20. In C, the P value for log non-REM AHI was 0.5. ABPM = ambulatory blood pressure monitoring.

Figure 2.

Adjusted odds ratio for estimating the risk of developing hypertension based on REM apnea–hypopnea index (AHI) severity categories. Conditional logistic regression model fitted to longitudinally explore the independent association between obstructive sleep apnea during REM sleep and development of hypertension. Estimates are adjusted for age, body mass index, waist-to-hip ratio, smoking, alcohol, and log non-REM AHI. The P value for log₂(non-REM AHI + 1) was 0.28.