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Blood Pressure Variability in Obstructive Sleep Apnoea: Data from 4 Randomised Controlled CPAP Withdrawal Trials


Lettau, Franziska; Schwarz, Esther I; Stradling, John R; Kohler, Malcolm (2017). Blood Pressure Variability in Obstructive Sleep Apnoea: Data from 4 Randomised Controlled CPAP Withdrawal Trials. Respiration, 93(5):311-318.

Abstract

BACKGROUND Increased daytime blood pressure variability (BPV) is associated with cardiovascular risk. Preliminary data suggest that obstructive sleep apnoea (OSA) might contribute to increased daytime BPV. OBJECTIVE The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) therapy withdrawal on daytime BPV. METHODS A total of 183 patients previously diagnosed with OSA and treated with CPAP were randomised to either continue or withdraw from CPAP within 4 trials. Office morning BP was measured in triplicate at baseline and at follow-up (day 14). In addition, the participants performed BP measurements at home on a daily basis (days 1-13). The main outcome of interest was the treatment effect on within-visit BPV expressed as the standard deviation (SD) of the triplicate measurements. Additional outcomes included morning home BPV and day-to-day home BPV. RESULTS Within-visit variability in systolic BP significantly increased in response to recurrence of OSA in the CPAP withdrawal group (difference between groups in SD of systolic BPV, +1.14 mm Hg, 95% CI +0.20/+2.09, p = 0.02). There was no statistically significant effect on within-visit variability in diastolic BP (p = 0.38) or heart rate (p = 0.07). Neither morning home BP variability (systolic BPV, p = 0.81; diastolic BPV, p = 0.46) nor day-to-day variability in home BP measurements (systolic BPV, p = 0.61; diastolic BPV, p = 0.58) differed significantly between the groups. CONCLUSION CPAP withdrawal results in a minor increase in within-visit variability in office systolic BP, but it has no effect on home BPV or day-to-day BPV. Although the treatment effect may be blunted by antihypertensives, it is unlikely that OSA contributes to cardiovascular risk via elevated daytime BPV.

Abstract

BACKGROUND Increased daytime blood pressure variability (BPV) is associated with cardiovascular risk. Preliminary data suggest that obstructive sleep apnoea (OSA) might contribute to increased daytime BPV. OBJECTIVE The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) therapy withdrawal on daytime BPV. METHODS A total of 183 patients previously diagnosed with OSA and treated with CPAP were randomised to either continue or withdraw from CPAP within 4 trials. Office morning BP was measured in triplicate at baseline and at follow-up (day 14). In addition, the participants performed BP measurements at home on a daily basis (days 1-13). The main outcome of interest was the treatment effect on within-visit BPV expressed as the standard deviation (SD) of the triplicate measurements. Additional outcomes included morning home BPV and day-to-day home BPV. RESULTS Within-visit variability in systolic BP significantly increased in response to recurrence of OSA in the CPAP withdrawal group (difference between groups in SD of systolic BPV, +1.14 mm Hg, 95% CI +0.20/+2.09, p = 0.02). There was no statistically significant effect on within-visit variability in diastolic BP (p = 0.38) or heart rate (p = 0.07). Neither morning home BP variability (systolic BPV, p = 0.81; diastolic BPV, p = 0.46) nor day-to-day variability in home BP measurements (systolic BPV, p = 0.61; diastolic BPV, p = 0.58) differed significantly between the groups. CONCLUSION CPAP withdrawal results in a minor increase in within-visit variability in office systolic BP, but it has no effect on home BPV or day-to-day BPV. Although the treatment effect may be blunted by antihypertensives, it is unlikely that OSA contributes to cardiovascular risk via elevated daytime BPV.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Pneumology
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2017
Deposited On:23 Jan 2018 15:07
Last Modified:30 Mar 2018 00:00
Publisher:Karger
ISSN:0025-7931
OA Status:Closed
Publisher DOI:https://doi.org/10.1159/000465528
PubMed ID:28351060

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