Clinical trial NCT00843583: A Cross-sectional Study of the Occurrence and Effect of Obstructive Sleep Apnea in Subjects With Resistant Hypertension
Official title: A Cross-sectional Study of the Occurrence and Effect of Obstructive Sleep Apnea in Subjects With Resistant Hypertension
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Obstructive Sleep Apnea
Resistant Hypertension
Keywords: prevalence
obstructive sleep apnea
resistant hypertension
Lead sponsor: The University of Hong Kong
Sponsor class: OTHER
First posted: 2009-02-13
Enrollment: 96
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_ONLY
Time perspective: CROSS_SECTIONAL
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.

Brief summary: 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

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.

Eligibility criteria: 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

Primary outcomes:
measure: ambulatory blood pressure
timeFrame: 24 hour
Secondary outcomes:
Other outcomes:
Locations:
city: Hong Kong
country: Hong Kong
facility: Department of Medicine, The University of Hong Kong, Queen Mary Hospital
Study officials:
affiliation: Department of Medicine, The University of Hong Kong
name: Sau Man Mary Ip, MD
role: PRINCIPAL_INVESTIGATOR
References:
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citation: Pepperell JC, Ramdassingh-Dow S, Crosthwaite N, Mullins R, Jenkinson C, Stradling JR, Davies RJ. Ambulatory blood pressure after therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised parallel trial. Lancet. 2002 Jan 19;359(9302):204-10. doi: 10.1016/S0140-6736(02)07445-7.
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citation: Norman D, Loredo JS, Nelesen RA, Ancoli-Israel S, Mills PJ, Ziegler MG, Dimsdale JE. Effects of continuous positive airway pressure versus supplemental oxygen on 24-hour ambulatory blood pressure. Hypertension. 2006 May;47(5):840-5. doi: 10.1161/01.HYP.0000217128.41284.78. Epub 2006 Apr 3.
citation: Calhoun DA, Jones D, Textor S, Goff DC, Murphy TP, Toto RD, White A, Cushman WC, White W, Sica D, Ferdinand K, Giles TD, Falkner B, Carey RM. Resistant hypertension: diagnosis, evaluation, and treatment. A scientific statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research. Hypertension. 2008 Jun;51(6):1403-19. doi: 10.1161/HYPERTENSIONAHA.108.189141. Epub 2008 Apr 7.
citation: Logan AG, Perlikowski SM, Mente A, Tisler A, Tkacova R, Niroumand M, Leung RS, Bradley TD. High prevalence of unrecognized sleep apnoea in drug-resistant hypertension. J Hypertens. 2001 Dec;19(12):2271-7. doi: 10.1097/00004872-200112000-00022.
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citation: Lavie P, Hoffstein V. Sleep apnea syndrome: a possible contributing factor to resistant. Sleep. 2001 Sep 15;24(6):721-5. doi: 10.1093/sleep/24.6.721.
citation: Logan AG, Tkacova R, Perlikowski SM, Leung RS, Tisler A, Floras JS, Bradley TD. Refractory hypertension and sleep apnoea: effect of CPAP on blood pressure and baroreflex. Eur Respir J. 2003 Feb;21(2):241-7. doi: 10.1183/09031936.03.00035402.
citation: Lui MMS, Tse HF, Mak JCW, Lam DCL, Chan CWS, Chong PWC, Ip MSM. Untreated Obstructive Sleep Apnea Is Associated With Myocardial Injury Independent of Blood Pressure Control in Hypertension. J Clin Sleep Med. 2018 Nov 15;14(11):1841-1847. doi: 10.5664/jcsm.7476.