title: Appropriate use of nasal continuous positive airway pressure decreases elevated C-reactive protein in patients with obstructive sleep apnea.
abstract: BACKGROUND
  C-reactive protein (CRP) is an important risk factor for cardiovascular disease. Furthermore, it has been reported that levels of CRP are increased in patients with obstructive sleep apnea (OSA). The aim of this study was to examine the effects of long-term therapy with nasal continuous positive airway pressure (nCPAP) on CRP levels and to investigate whether compliance with nCPAP therapy more effectively attenuated markers of systemic inflammation in patients with OSA.
  
  
  RESULTS
  Fifty-five patients (mean [+/- SEM] age, 55 +/- 2 years; 44 male patients, 11 female patients) with newly diagnosed moderate-to-severe OSA (apnea-hypopnea index > 20 events/h) were studied before and after 6 months of nCPAP treatment. There was a significant reduction in CRP levels after nCPAP therapy (before nCPAP therapy, 0.23 +/- 0.03 mg/dL; after nCPAP therapy, 0.17 +/- 0.02 mg/dL; p < 0.01). Additionally, we divided these patients into two groups based on adherence to nCPAP therapy. A group of patients using nCPAP > 4 h/d and > 5 d/wk were designated as the good compliance group. The decrease in CRP concentration was significant (before nCPAP therapy, 0.23 +/- 0.04 mg/dL; after nCPAP therapy, 0.16 +/- 0.03 mg/dL; p < 0.05) in the good compliance group but not in the poor compliance group (before nCPAP therapy, 0.24 +/- 0.05 mg/dL; after nCPAP therapy, 0.20 +/- 0.05 mg/dL; p = 0.21). Furthermore, we divided those patients into a high CRP group (>/= 0.2 mg/dL) and a normal CRP group (< 0.2 mg/dL) before nCPAP therapy. The significant decrease in CRP levels in the good compliance group was evident only in those patients with an initially elevated CRP level (before nCPAP therapy, 0.48 +/- 0.08 mg/dL; after nCPAP therapy, 0.29 +/- 0.06 mg/dL; p < 0.05).
  
  
  CONCLUSIONS
  Appropriate use of nCPAP in patients with OSA may be required to decrease elevated CRP levels, with possible implications for cardiovascular morbidity and mortality.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Ishida
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan. Electronic address: mkato@grape.med.tottori-u.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kato
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Yanagihara
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Kinugasa
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, Tochigi, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kotani
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Igawa
authors.affiliation: Department of Genetic Medicine and Regenerative Therapeutics, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hisatome
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Tottori University, Yonago, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Shigemasa
authors.affiliation: Division of Cardiovascular Disease, Mayo Clinic, Rochester, MN.
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
mesh_terms: D001794:Blood Pressure; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D045422:Continuous Positive Airway Pressure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D008055:Lipids; D002097:C-Reactive Protein