Efficacy of Continuous Positive Airway Pressure in Reducing Oxidative Stress in Individuals With Sleep Apnea (SASS)

August 17, 2017 updated by: Reena Mehra, Case Western Reserve University

Oxidative Stress in Sleep Apnea and Cardiac Disease

Sleep-disordered breathing (SDB) is a condition in which a person experiences frequent breathing pauses during sleep, also known as sleep apnea. There is evidence that the recurrent sleep arousal and associated shortage of oxygen in the body may increase risk for cardiovascular disease (CVD). It is believed that treatment with continuous positive airway pressure (CPAP) may reduce certain risk factors for heart disease, including markers of inflammation and oxidative stress. This study will evaluate the effectiveness of CPAP in reducing CVD risk factors in people with SDB.

Study Overview

Detailed Description

It is estimated that 18 million Americans are affected by SDB. SDB involves repeated sleep arousal caused by breathing difficulties. These frequent sleep disruptions may cause a person to experience daytime drowsiness, impaired mental functioning, and trouble concentrating or staying alert. SDB is also associated with an increased risk of certain cardiovascular diseases, such as high blood pressure and heart disease. Researchers believe that increased oxidative stress and inflammation associated with SDB may play a role in the physiologic pathway linking SDB and CVD. However, more information on the SDB-CVD relationship is needed to be able to identify risk factors for CVD and to discover the best means of treatment. CPAP, a current treatment for SDB, acts by delivering air through a mask during sleep. CPAP helps improve overnight breathing and quality of sleep and may, in turn, decrease oxidative stress and associated CVD risks. This study will compare the effectiveness of CPAP versus placebo CPAP in reducing CVD risk factors, such as oxidative stress markers, in people with SDB.

Participation in this study will last between 2.5 and 4 months and will include four to five study visits. During the first study visit, participants will undergo a CPAP titration study, which will involve appropriate CPAP mask fitting and an overnight sleep test to determine the best CPAP pressure, as well as a lower placebo pressure, for each participant. Participants will also be provided educational information on diet, sleep, and the use of CPAP as a treatment for sleep apnea. After the titration study, participants will be asked to wear their fitted CPAP mask every night for the next 2 weeks, during which they will use the lower (placebo) pressure one week and use the higher pressure the other week. During this time, a technician will contact participants every 3 to 4 days to address any questions or problems with the CPAP equipment.

One month later, participants who were able to tolerate and use CPAP most nights will attend Visit 2. This second visit will include an overnight sleep study without wearing the CPAP mask; blood and saliva collection; cheek brushing for genetic material; tests on diabetes, artery stiffness, and circulation; body fat measurements; and questionnaires. Participants will then be randomly assigned to use either the higher pressure CPAP or the lower pressure CPAP for 8 weeks. Visit 3 will occur 1 week after beginning CPAP treatment and will include a fasting blood test. During treatment, participants will be periodically contacted by a technician to check on equipment status.

Upon completing treatment, participants will undergo repeat tests from Visit 2, except that they will wear the CPAP mask in the overnight sleep test. This fourth study visit will mark the completion of treatment for participants assigned to the lower pressure CPAP. Participants assigned to the higher pressure CPAP will be asked to use CPAP for 4 more weeks. These participants will return at the end of the 4 weeks for a final visit, which will include a repeat sleep study and other testing.

Study Type

Interventional

Enrollment (Actual)

153

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Ohio
      • Cleveland, Ohio, United States, 44106
        • University Hospitals Case Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Moderate to severe sleep disordered breathing (SDB) (Apnea Hypopnea Index [AHI] greater than or equal to 15) diagnosed within the 2 months before study entry
  • Able to participate in more than two overnight/daytime sleep and physiologic assessments over a 2.5-month period

Exclusion Criteria:

  • Current or planned use of specific sleep apnea treatments (e.g., CPAP, oral appliance) outside of the study
  • Anticipated upper airway surgery or gastric bypass surgery in the 4 months after study completion
  • Supplemental oxygen use
  • Primary sleep disorder other than sleep apnea (e.g., periodic limb movement disorder)
  • Severe chronic insomnia or circadian rhythm disorder with less than 4 hours of sleep per night, chronic problems falling asleep within 1 hour of bedtime, or chronic problems with early morning awakenings
  • Unstable medical conditions (e.g., new onset or changing angina; heart attack or congestive heart failure exacerbation documented within the 6 months before study entry; high grade cardiac dysrhythmia/heart block; known unaddressed coronary artery disease by history, angina, stroke, or uncontrolled hypertension or diabetes mellitus; thyroid disorder; cirrhosis; a non-skin cancer diagnosed within the 2 years before study entry)
  • Inadequately treated psychiatric disorders or compromised competence
  • Daytime sleepiness with reports of sleepiness while driving or during other situations that would present a risk for the subject or public (e.g., operating heavy equipment)
  • Alcohol abuse
  • Pregnancy
  • Use of oral corticosteroids

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: Sham CPAP
Participants will receive sham continuous positive airway pressure (CPAP) for a 2 month period. Sham CPAP involves wearing a device that appears similar to a standard CPAP device, but administers a negligible pressure. Adherence will be tracked while the participant wears the device.
Participants will use the lower pressure CPAP every night for 8 weeks.
Active Comparator: Treatment CPAP
Participants will receive continuous positive airway pressure for a 2 month period. The optimal treatment pressure will be identified during a titration study prior to trial enrollment. Adherence will be tracked while the participant wears the device.
Participants will use the higher pressure CPAP, as determined by an in-laboratory attended titration study, every night for 12 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
F2-isoprostanes/Cr
Time Frame: Measured between baseline and after treatment
Oxidative stress outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment
Myeloperoxidase
Time Frame: Measured between baseline and after treatment
Oxidative stress outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Arterial BP, Evening
Time Frame: Measured between baseline and after treatment
Blood pressure outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment
Pulse Wave Velocity, Evening
Time Frame: Measured between baseline and after treatment
Pulse wave analysis outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment
IL-6
Time Frame: Measured between baseline and after treatment
Measures of inflammation outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment
Mean Arterial BP, Morning
Time Frame: Measured between baseline and after treatment
Blood pressure outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between baseline and after treatment
sIL-6R
Time Frame: Measured between baseline and after treatment
Measures of inflammation outcome, logarithm transformed before analysis due to skewed distribution, analyzed change of from baseline with adjustment of baseline. The least squares mean is transformed back to present the percent change from baseline.
Measured between baseline and after treatment
Pulse Wave Velocity, Morning
Time Frame: Measured between Months 2 and 3 of treatment
Pulse wave analysis outcome, analyzed absolute change from baseline, with adjustment of baseline
Measured between Months 2 and 3 of treatment
Augmentation Index, Evening
Time Frame: Measured between Months 2 and 3 of treatment
Pulse wave analysis outcome (a ratio of the augmentation of central aortic pressure by a reflected pulse wave, calculated from the blood pressure waveform), analyzed absolute change from baseline, with adjustment of baseline
Measured between Months 2 and 3 of treatment
Augmentation Index, Morning
Time Frame: Measured between Months 2 and 3 of treatment
Pulse wave analysis outcome (a ratio of the augmentation of central aortic pressure by a reflected pulse wave, calculated from the blood pressure waveform), analyzed absolute change from baseline, with adjustment of baseline
Measured between Months 2 and 3 of treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Reena Mehra, MD, MS, University Hospitals Cleveland Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2006

Primary Completion (Actual)

July 1, 2011

Study Completion (Actual)

July 1, 2011

Study Registration Dates

First Submitted

January 25, 2008

First Submitted That Met QC Criteria

January 25, 2008

First Posted (Estimate)

February 6, 2008

Study Record Updates

Last Update Posted (Actual)

September 15, 2017

Last Update Submitted That Met QC Criteria

August 17, 2017

Last Verified

August 1, 2017

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Undecided

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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