We investigated the relationship between ambulatory blood pressure (BP) and oxygen desaturation index (ODI), while accounting for pulse rate and age. ODI was assessed by overnight finger pulse oximetry in 2342 participants on the day of ambulatory BP monitoring, and calculated as the number of desaturation episodes per sleeping hour. Both BP and pulse rate increased significantly (P ≤ .006) from normal (< 5 events/h) to mildly (5-14), moderately (15-30), and severely (≥ 30 events/h) elevated ODI. The association for BP was substantially attenuated by accounting for pulse rate (partial r² from .003-.012 to .002-.006). In adjusted analysis, the associations of 24-hour diastolic BP and 24-hour pulse rate with ODI were dependent on age (P ≤ .0001) and only significant in younger subjects (< 60 years, P ≤ .0001). In conclusion, the association between ambulatory BP and ODI was partially mediated by pulse rate, a measure of sympathetic activity, and was more prominent in younger subjects.
Keywords: age; ambulatory blood pressure; hypertension; oxygen desaturation; pulse oximetry; pulse rate.
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