A Cross-sectional Study of the Occurrence and Effect of Obstructive Sleep Apnea in Subjects With Resistant Hypertension

May 2, 2017 updated by: The University of Hong Kong
This study aims to investigate the prevalence of obstructive sleep apnea (OSA) in subjects with resistant hypertension and to evaluate the relationship between parameters of OSA severity and blood pressure control

Study Overview

Status

Completed

Conditions

Detailed Description

Obstructive sleep apnea (OSA) is characterized by intermittent upper airway collapse during sleep, which results in hypoxia, arousals and surge in sympathetic activity. There is robust evidence to support a contributing role of OSA in hypertension (HT). The Sleep Heart Health Study (1), which recruited more than 6000 subjects having polysomnogram at home, found an independent association between OSA and HT. The adjusted odds ratio was 1.37 for subjects with and apnea-hypopnea index >= 30/hour compared to those without apnea. The Wisconsin Sleep Cohort Study , which provided prospective longitudinal follow-up for OSA subjects over 4 years, have shown dose dependency of the severity of OSA and the risk of development of HT. Current available data suggests that in hypertensive patients with severe OSA, there is a BP drop of about 10mmHg with CPAP treatment (2-5). The blood pressure (BP) lowering effect of CPAP treatment in the group with mild asymptomatic OSA is less consolidated.

The relationship between BP and risk of cardiovascular events is continuous, consistent, and independent of other risk factors. A strict blood pressure control is imperative in subjects with diabetes mellitus or renal impairment. Resistant hypertension is defined as blood pressure that remains above goal in spite of concurrent use of 3 antihypertensive agents of different classes. (6) Resistant hypertension is defined in order to identify patients who are at risk of having secondary causes of hypertension, and who may benefit from specific diagnostic and therapeutic applications. Despite the fact that OSA is listed as one of the causes of resistant HT (6), paucity of works has demonstrated the scale of problems of untreated OSA in subjects with resistant HT. (7-9) There is so far one study demonstrating the beneficial effect of CPAP treatment in subjects with resistant HT, though no randomization was implemented and the sample size was limited (n=11). (10) We aim at conducting a cross-sectional study to explore the situation which would guide further clinical trial.

Study Type

Observational

Enrollment (Anticipated)

96

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

  • Hong Kong
      • Hong Kong, Hong Kong, 852
        • Department of Medicine, The University of Hong Kong, Queen Mary Hospital

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

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Consecutive sampling of subjects who attend Hypertension clinic , Department of Medicine, Queen Mary Hospital, and who fulfill the inclusion criteria.

Description

Inclusion Criteria:

  • ≧ 3 anti-HT drugs
  • age 18-65
  • mentally fit for signing an informed written consent

Exclusion Criteria:

  • moderate renal impairment (glomerular filtration rate <30 mL/min/m2 )
  • endocrine/renal/cardiac causes of secondary HT
  • congestive heart failure and clinically fluid overloaded
  • On drugs that elevate BP e.g. alcohol, NSAID, steroid

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

Cohorts and Interventions

Group / Cohort
resistant hypertension subjects
subjects with resistant hypertension

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
ambulatory blood pressure
Time Frame: 24 hour
24 hour

Collaborators and Investigators

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

Sponsor

The University of Hong Kong

Investigators

  • Principal Investigator: Sau Man Mary Ip, MD, Department of Medicine, the University of Hong Kong

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

February 1, 2009

Primary Completion (Actual)

December 1, 2012

Study Completion (Actual)

December 1, 2012

Study Registration Dates

First Submitted

February 12, 2009

First Submitted That Met QC Criteria

February 12, 2009

First Posted (Estimate)

February 13, 2009

Study Record Updates

Last Update Posted (Actual)

May 3, 2017

Last Update Submitted That Met QC Criteria

May 2, 2017

Last Verified

May 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NCT00843583

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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