© Springer International Publishing AG 2017 323
A. Covic et al. (eds.), Resistant Hypertension in Chronic Kidney Disease,
DOI 10.1007/978-3-319-56827-0_20
Chapter 20
The Effect of CPAP Therapy on Resistant
Hypertension in Obstructive Sleep Apnea
Syndrome Patients with Chronic Kidney
Disease
Abdullah Özkök, Asiye Kanbay, and Oğuz Köktürk
Obstructive Sleep Apnea Syndrome (OSAS), Hypertension
(HT) and Chronic Kidney Disease (CKD)
Obstructive sleep apnea syndrome (OSAS) is caused by repeated episodes of
apnea- hypopnea due to upper airway obstruction leading to oxygen desaturation.
OSAS is an independent risk factor for cardiovascular disease including hyperten-
sion, coronary artery disease, and stroke [ 1 , 2 ]. OSAS is common affecting 5–20%
of the general population, and it is still underdiagnosed in many cases [ 3 , 4 ].
A strong relationship exists between OSAS and hypertension (HT). Approximately
half of the patients with OSAS are hypertensive, and 30–40% of patients with HT
have been reported to have OSAS [ 5 , 6 ]. In a prospective study, patients with OSAS
were found to have three times higher risk of HT [ 7 ]. Furthermore, a dose-response
relationship between the severity of OSAS and HT was detected in this study.
Confirming this finding, in Wisconsin Sleep Cohort Study, apnea-hypopnea index
was found to be associated linearly with higher 24-h ambulatory blood pressure
(BP) levels [ 8 ]. The important role of OSAS in hypertension has also been recog-
nized by the Joint National Committee VII report [ 9 ], American Heart Association
[ 10 ], and the European Society of Hypertension Guidelines [ 11 ].
OSAS may also be related to the development of incident HT in normotensive
patients; however controversy exists in this issue. In the Wisconsin Sleep Cohort
A. Özkök
Istanbul Medeniyet University, Goztepe Education and Research Hospital,
Section of Nephrology, Istanbul, Turkey
A. Kanbay (*)
Istanbul Medeniyet University, Faculty of Medicine, Department of Pulmonary Medicine,
Istanbul, Turkey
e-mail: [email protected]
O. Köktürk
Gazi University, Faculty of Medicine, Department of Pulmonary Medicine, Ankara, Turkey