Effect of Continuous Positive Airway Pressure (CPAP) Therapy on Changes of Blood Pressure Between Day and Night

Study Overview
=================
Brief Summary
-----------------
to test whether using CPAP can restore the normal pattern of drop of blood pressure during sleep.

Detailed Description
-----------------
OBJECTIVE: To investigate the effect of CPAP therapy on the restoration of the normal diurnal blood pressure pattern. Possible improvement of the circadian dipper pattern after CPAP therapy, with or without a decrease in the mean blood pressure, might constitute an additional potential benefit of CPAP therapy in reducing cardiovascular risk in patients with OSA. STUDY DESIGN AND METHODS: Patients diagnosed with OSA at the sleep center will undergo blood pressure monitoring by measuring the blood pressure every half hour during sleep study. Patients with normal circadian BP changes are treated with CPAP as indicated. Patients with non-dipping BP pattern will be approach to join our study. The patients will receive CPAP therapy. The trial period will be 6 weeks. At the end of the trial, the patients from both treatment arms will undergo a second BP monitoring according to our above-mentioned protocol (systolic, diastolic and mean BP) to determine the circadian BP changes. Apnea-Hypopnea index will be calculated to reflect on the compliance with our therapy. Thus, patients could be divided into two study groups according to their objective compliance. Baseline population characteristics between the placebo group and CPAP group will be noted. These include apnea-hypopnea index (AHI), medications, other co morbidities and other factors that might affect the normal circadian BP dipping pattern including factors affecting the volume status i.e. diabetes, renal failure, uncontrolled diabetes. Any new medications added during the 6 weeks trial period will be noted. STATISTICAL ANALYSIS: The difference in daytime and nighttime BP pattern will be noted between the treated (CPAP) and the non-compliant groups. The circadian BP variation will be recorded in both groups. Changes in the circadian BP pattern will be assessed on an intention-to-treat basis. The odds ratio, p value and confidence interval will be calculated. Correlation between the dipping/non-dipping pattern with CPAP compliance, severity of OSA and number of antihypertensive drugs will be studied as well

Official Title
-----------------
Changes In Diurnal Blood Pressure Pattern In Obstructive Sleep Apnea (OSA) Patients After CPAP Therapy

Conditions
-----------------
Obstructive Sleep Apnea, Diurnal Blood Pressure

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 1. All patients with OSA who don't meet the above mentioned exclusion criteria Exclusion Criteria: Patients who have a normal diurnal sleep pattern (i.e. decrease of more than 30% of the systolic BP at night time) Patients who are on three or more antihypertensives whose blood pressure is not controlled. Patients previously treated with CPAP therapy within the past 3 months

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 1<br>Compliant with CPAP | |
| 2<br>noncompliant with CPAP | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| drop of Blood pressure at night |  | 6 weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
CPAP, diurnal blood pressure, obstructive sleep apnea, 24 hour blood pressure monitor