Abstract
After 65 years old, the specific impact of unrecognized sleep-related breathing disorders (SRBD) on 24-hour blood pressure (BP) levels remains still debated. We tested the cross-sectional relationship between the severity of obstructive sleep apnoea/hypopnoea (OSAH) and the increase of BP measured with an ambulatory BP monitoring in the PROOF-SYNAPSE cohort.
470 subjects (age: 68 years) neither treated for hypertension nor diagnosed for SRBD were included. They all underwent ambulatory blood pressure monitoring, (ABP) and unattended at-home polygraphic studies. OSAH was defined by an apnoea plus hypopnoea index (AHI) above 15·hour−1. The severity of sleep apnoea was also quantified as the index of dips in oxyhemoglobin saturation > 3% (ODI). Results are expressed in per- protocol analysis.
Severe OSAH (AHI>30·h−1, 17% of subjects) was associated with a significant 5 mmHg increase in both diurnal and nocturnal Systolic BP, and with a nocturnal 3 mmHg increase in Diastolic BP. Systolic (mean SBP>135 mmHg) or diastolic (mean DBP>80 mmHg) hypertension were more frequently encountered in subjects suffering from moderate (AHI:15–30) or severe OSAH. After adjustment, the independant association between severe OSAH and 24-hour systolic hypertension remained significant (OR 2.42; CI[1.1–5.4]). The relationship was further reinforced when SRBD severity was expressed using ODI>10·h−1.
The impact of unrecognized SRBD on blood pressure levels also exists at 68 years old. The hypoxemic load appears the pathophysiological cornerstone for such a relationship.
- ERS