IMPACT OF LONG-TERM USE OF CPAP TREATMENT ON BLOOD PRESSURE AMONG REFRACTORY HYPERTENSIVE PATIENTS WITH OBSTRUCTIVE SLEEP APNEA

Abstract

Objective: To assess blood pressure response to long-term continuous positive airway pressure (CPAP) treatment among patients with refractory hypertension (RfHTN) with moderate and severe obstructive sleep apnea (OSA). Design and method: An observational prospective study was performed in 26 patients (35.7% male, average age 59.3 ± 7.9 years) with diagnostic of RfHTN and moderate and severe OSA who were divided in 2 groups to use CPAP (CPAP group, n = 13) or not (control group, n = 15). All of them were submitted to clinical follow-up and their anti-hypertensive medication was adjusted according to the assistant physician. 24-hour ABPM was performed both at the beginning and at the end of the study. Primary outcomes were changes in office and ambulatory blood pressure (BP) and BP control. The comparison between groups of BP changes were calculated by a general linear model with group allocation as a fixed factor and adjusted by its respective BP basal values in addition to gender and age. Results: The median follow-up time was 68 months (IQR: 49–81 months). CPAP and control groups were similar in their baseline demographic, anthropometric, laboratory characteristics, and office and ambulatory BP. They had mean systolic and diastolic 24-hour BP of 142 (15) and 83 (14), respectively. At the end of follow-up, refractory patients using CPAP had a reduction of 8.5 and 5.0 mmHg of office systolic and diastolic BP with an intergroup difference (CPAP and control) of 13.5 (-15.2 – 42.3) mmHg and 10.1 (-7.5 – 5.4) mmHg, respectively. The most important difference between groups was noticed at nighttime with an intergroup difference of 10.0 (-8.6 – 28.7) mmHg of systolic BP and 6.7 (-3.9 – 17.3) mmHg of nighttime diastolic BP. Out of 28 initial refractory patients, 12 are not refractory anymore, being 3 (20%) in control group and 9 (69.2%) in CPAP group with a significant difference between the groups (p = 0.02) Conclusions: Long-term use of CPAP among refractory hypertensive patients with moderate/severe OSA seems to be effective to reduce and control blood pressure measured both in the office BP and 24-hour ABPM, especially lowering nighttime blood pressure.