Ambulatory blood pressure in relation to oxygen desaturation index as simultaneously assessed by nighttime finger pulse oximetry at home

Abstract

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.

Figure 1

Prevalence of oxygen desaturation index ≥15 events/h according to gender, age (left panel) and body mass index groups (right panel). Symbols indicate the prevalence for each subgroup. The P values for trend are given for men (filled symbols with solid line) and women (open symbols with dashed line) separately. The number of patients is given alongside the symbols. For analysis according to body mass index, we excluded 18 subjects who did not have information on body height or body weight

Figure 2

Adjusted 24‐h, daytime and nighttime blood pressure according to oxygen desaturation index group. Symbols indicate mean values of 24‐h (dots with solid line), daytime (filled squares with dashed line) and nighttime blood pressure (open squares with dashed line), adjusted for age, gender, body mass index, antihypertensive treatment, Epworth Sleepiness Scale and pulse rate. The P values for trend and the number of subjects are given along the line and at the bottom, respectively

Figure 3

Relationship between 24‐h pulse rate (left panel) and 24‐h diastolic blood pressure (right panel) with oxygen desaturation index according to age group. Symbols represent mean values of 24‐h ambulatory pulse rate and 24‐h diastolic blood pressure, for each subgroup according to age and oxygen desaturation index. The number of subjects for each subgroup is given alongside the symbols. The P values for interaction between age and oxygen desaturation index in relation to 24‐h ambulatory pulse rate and 24‐h diastolic blood pressure are given

Figure 4

Relationship between 24‐h pulse rate (left panel) and 24‐h diastolic blood pressure (right panel) with oxygen desaturation index according to sex group. Symbols represent mean values of 24‐h ambulatory pulse rate and 24‐h diastolic blood pressure, for each subgroup according to sex and oxygen desaturation index. The number of subjects for each subgroup is given alongside the symbols. The P values for interaction between sex and oxygen desaturation index in relation to 24‐h ambulatory pulse rate and 24‐h diastolic blood pressure are given