Relative spectral power quantifying the distribution of intermittent hypoxemia in obstructive sleep apnea is strongly associated with hypertension

Abstract

Study objectivesTo investigate the association between the periodicity of distribution of intermittent hypoxemia (IH) and hypertension in adults with obstructive sleep apnea (OSA) and search for an index to quantify the association. MethodsSamples were derived from two cross-sectional studies: The Sleep Heart Health Study (SHHS) including 3991 adults with age 64.7 ± 10.9 years; and the Chinese Changgung Sleep Health Study (CSHS) including 906 adults with age 59.5 ± 12.4 years. Spectral analysis of peripheral oxygen saturation (SpO2) was performed and the relative spectral power (PFR) in the frequency band of 0.011–0.037 Hz (PFR0.011–0.037Hz) was extracted to quantify the periodic distribution of IH. Multiple logistic regression models were used to calculate the partially and fully adjusted odd ratios for PFR0.011–0.037Hz. ResultsPFR0.011–0.037Hz was significantly higher in the hypertension group than non-hypertension group (44.4% ± 0.3% vs. 42.1% ± 0.3%, p < 0.001 in SHHS and 57.4% ± 0.7% vs. 50.5% ± 0.8%, p < 0.001 in CSHS). In the fully adjusted model, individuals in the SHHS with PFR0.011–0.037Hz in the highest quintiles had an odd ratio of 1.33 [95% confidence interval (CI) 1.06–1.67]. Similarly, the group in the CSHS with PFR0.011–0.037Hz in the highest quintile had an odd ratio of 3.08 (95% CI 1.80–5.28). ConclusionsWe developed an IH distribution measure which is strongly associated with hypertension independent of multiple confounding variables. The finding suggests that the periodic distribution of sleep related upper airway obstructions is an essential hypertension characterizing feature.