Chest
Volume 132, Issue 6, December 2007, Pages 1847-1852
Journal home page for Chest

Original Research
Sleep Medicine
Long-term Effect of Continuous Positive Airway Pressure on BP in Patients With Hypertension and Sleep Apnea

https://doi.org/10.1378/chest.07-1478Get rights and content

Objective: To analyze the long-term effect of continuous positive airway pressure (CPAP) on ambulatory BP in patients with obstructive sleep apnea (OSA) and hypertension, and to identify subgroups of patients for whom CPAP could be more effective.

Methods

We conducted a prospective, long-term follow-up trial (24 months) in 55 patients with OSA and hypertension (mean CPAP use, 5.3 ± 1.9 h/d [± SD]). Twenty-four–hour ambulatory BP monitoring (ABPM) was measured at baseline and after intervention with CPAP on an intention-to-treat basis. In addition, the correlation between the changes in 24-h mean arterial pressure (24hMAP) and CPAP compliance, OSA severity, and baseline ABPM was assessed.

Results

At the end of follow-up, a significant decrease was shown only in diastolic BP (− 2.2 mm Hg; 95% confidence interval [CI], − 4.2 to − 0.1; p = 0.03) but not in 24hMAP or other ABPM parameters. However, a correlation between changes in 24hMAP and baseline systolic BP (r = − 0.43, p = 0.001), diastolic BP (r = − 0.38, p = 0.004), and hours of use of CPAP (r = − 0.30, p = 0.02) was observed. A significant decrease in the 24hMAP was achieved in a subgroup of patients with incompletely controlled hypertension at entry (− 4.4 mm Hg; 95% CI, − 7.9 to − 0.9 mm Hg; p = 0.01), as well as in those with CPAP compliance > 5.3 h/d (− 5.3 mm Hg; 95% CI, − 9.5 to − 1.2 mm Hg; p = 0.01). Linear regression analysis showed that baseline systolic BP and hours of CPAP were independent predictors of reductions in BP with CPAP.

Conclusion

Long-term CPAP reduced BP modestly in the whole sample. However, patients with higher BP at entry and good CPAP compliance achieved significant reductions in BP.

Section snippets

Design and Patients

A prospective, long-term follow-up trial of consecutive patients referred to the Sleep Disorders Unit of the Valme University Hospital (Seville, Spain) between January and September 2003 with a suspected diagnosis of OSA was conducted. Patients were considered for inclusion if they were between 30 and 70 years of age with an apnea-hypopnea index (AHI) ≥ 10/h in conventional polysomnography, and a previous diagnosis of hypertension and receiving treatment with at least one drug for at least 3

Results

Seventy patients fulfilled the inclusion criteria, but 4 patients declined to take part in the study (2 patients lived too far away, and 2 patients refused treatment with CPAP). The remaining 66 patients began the study. Seven patients were unavailable for follow-up (three patients could not be contacted, and four patients refused follow-up visits), and four patients withdrew CPAP before the end point and were thus excluded. Finally, 55 patients completed the study. The study sample was similar

Discussion

The results of this study show that long-term CPAP treatment increased the proportion of patients who regained the normal circadian dipping pattern and showed significant reductions in diastolic BP, but only a modest effect on the rest of ABPM parameters in patients with OSA and hypertension undergoing antihypertensive treatment. Most importantly, in the subgroups of patients with good compliance or poorly controlled hypertension at entry, CPAP was especially effective in causing significant

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    This study was performed without subsidy or financial support.

    The authors have no conflicts of interest to disclose.

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