Abstract
RATIONALE
A close relationship between obstructive sleep apnea (OSA) and blood pressure (BP) impairments, including an increased risk for nocturnal nondipping, has been consistently observed. However, the precise mechanisms of this interaction are
incompletely understood. Here, we characterized the polysomnography (PSG) parameters associated with alterations in the circadian BP pattern aiming to identify the main contributors to explain the nondipper profile in OSA.
METHODS
Observational, prospective and multicentric study including subjects referred to the sleep unit for suspected OSA. Following a PSG, subjects with an apnea-hypopnea index (AHI) ≥5 events/h were included. Two groups were established based on the 24-h ambulatory blood pressure monitoring (ABPM) dipping ratio (DR; night/day BP ratio): dippers (DR≤0.9) and nondippers (DR>0.9). Adjusted logistic regression models were used to examine the individual associations of PSG parameters with the risk of nondipping. Multivariate variable selection processes based on least absolute shrinkage and selection operator (LASSO) and Random Forest were applied to identify the risk factors for nondipping.
RESULTS
The cohort consisted of 299 patients: 131 (43.8%) dippers and 168 (56.2%) nondippers. A significant increase in the risk of presenting a nondipper BP pattern was found along with AHI gain [odds ratio (OR) (95% (CI) = 1.71 (1.28-2.28)], with severe OSA patients (AHI≥30 events/h) more likely to be nondippers than mild OSA patients (5≤AHI<15 events/h). The best AHI cutoff for predicting nondipper status was 25.2 events/h, increasing the OR (95% CI) to 3.50 (2.02-6.07) (Figure 1A). The hypopnea index [OR (95% CI) = 1.70 (1.27-2.26), TSat90 [OR (95% CI) = 1.41 (1.06-1.87)] and respiratory arousal index [OR (95% CI) = 1.74 (1.30-2.34)] were individually associated with the risk of a nondipping BP
pattern (Figure 1B). LASSO regression identified 5 predictors of nondipper status: respiratory arousal index, proportion of sleep time in stage N2, hypopnea index, use of antihypertensive drugs and female sex (Figure 1C). The top 5 predictive factors identified by random forest were related to macro- and microsleep structure, with the respiratory arousal index as the principal risk factor for the nondipper profile (Figure 1D).
CONCLUSIONS
The respiratory arousal index is a key OSA-related parameter associated with the loss of nocturnal BP dipping. Results suggest that sleep fragmentation is an important mechanistic pathway underlying the relationship between OSA and circadian BP abnormalities.
A close relationship between obstructive sleep apnea (OSA) and blood pressure (BP) impairments, including an increased risk for nocturnal nondipping, has been consistently observed. However, the precise mechanisms of this interaction are
incompletely understood. Here, we characterized the polysomnography (PSG) parameters associated with alterations in the circadian BP pattern aiming to identify the main contributors to explain the nondipper profile in OSA.
METHODS
Observational, prospective and multicentric study including subjects referred to the sleep unit for suspected OSA. Following a PSG, subjects with an apnea-hypopnea index (AHI) ≥5 events/h were included. Two groups were established based on the 24-h ambulatory blood pressure monitoring (ABPM) dipping ratio (DR; night/day BP ratio): dippers (DR≤0.9) and nondippers (DR>0.9). Adjusted logistic regression models were used to examine the individual associations of PSG parameters with the risk of nondipping. Multivariate variable selection processes based on least absolute shrinkage and selection operator (LASSO) and Random Forest were applied to identify the risk factors for nondipping.
RESULTS
The cohort consisted of 299 patients: 131 (43.8%) dippers and 168 (56.2%) nondippers. A significant increase in the risk of presenting a nondipper BP pattern was found along with AHI gain [odds ratio (OR) (95% (CI) = 1.71 (1.28-2.28)], with severe OSA patients (AHI≥30 events/h) more likely to be nondippers than mild OSA patients (5≤AHI<15 events/h). The best AHI cutoff for predicting nondipper status was 25.2 events/h, increasing the OR (95% CI) to 3.50 (2.02-6.07) (Figure 1A). The hypopnea index [OR (95% CI) = 1.70 (1.27-2.26), TSat90 [OR (95% CI) = 1.41 (1.06-1.87)] and respiratory arousal index [OR (95% CI) = 1.74 (1.30-2.34)] were individually associated with the risk of a nondipping BP
pattern (Figure 1B). LASSO regression identified 5 predictors of nondipper status: respiratory arousal index, proportion of sleep time in stage N2, hypopnea index, use of antihypertensive drugs and female sex (Figure 1C). The top 5 predictive factors identified by random forest were related to macro- and microsleep structure, with the respiratory arousal index as the principal risk factor for the nondipper profile (Figure 1D).
CONCLUSIONS
The respiratory arousal index is a key OSA-related parameter associated with the loss of nocturnal BP dipping. Results suggest that sleep fragmentation is an important mechanistic pathway underlying the relationship between OSA and circadian BP abnormalities.
| Original language | English |
|---|---|
| Article number | A5972 |
| Number of pages | 2 |
| Journal | American Journal of Respiratory and Critical Care Medicine |
| Volume | 207 |
| DOIs | |
| Publication status | Published - 2023 |
| Externally published | Yes |
| Event | 56º Congreso Nacional SEPAR - , Spain Duration: 8 Jun 2023 → … |
Keywords
- Obstructive sleep apnea
- Blood Pressure
- Nondipping