title: The relationship between high-sensitivity C-reactive protein levels and the severity of obstructive sleep apnea.
abstract: OBJECTIVE
  There is an increased risk of cardiovascular and cerebrovascular events in patients with obstructive sleep apnea (OSA). High-sensitivity C-reactive protein (hs-CRP) is a marker that predicts atherosclerotic complications. However, there are contradictory results about the correlation between serum hs-CRP levels and OSA severity. The purpose of this work was to evaluate the relationship between hs-CRP levels and the severity of OSA in newly diagnosed OSA patients.
  
  
  METHODS
  The study group was composed of 76 patients with clinical suspicion of OSA. Subjects with body mass indexes (BMI) ≥30 kg/m(2) were classified as obese. Full-night polysomnography (PSG) was performed on all patients. Patients with an apnea-hypopnea index (AHI) ≥5 were considered to have OSA, and patients with an AHI <5 were accepted as the control group. Blood samples were taken from all patients to analyze serum hs-CRP levels the morning after PSG.
  
  
  RESULTS
  The serum hs-CRP levels were significantly higher in the OSA group (4.03 ± 3.58 mg/L) than in the control group (2.41 ± 1.95 mg/L) (p = 0.013). This high level was positively correlated with BMI (r = 0.376, p = 0.001) and with AHI (r = 0.280, p = 0.014). In multiple regression analysis, elevated hs-CRP levels were associated with AHI (F = 3.293, p = 0.033), which was independent of obesity.
  
  
  CONCLUSIONS
  Patients with OSA have elevated serum levels of hs-CRP, a marker for inflammation and an independent risk predictor for cardiovascular morbidity. The severity of OSA is responsible for the elevation of hs-CRP.
authors.affiliation: Sleep Disorders Center, Atatürk Chest Diseases, Thoracic Surgery Training and Research Hospital, Ankara, Turkey. selmafiratguven@yahoo.com
authors.forename: Selma Firat
authors.initials: SF
authors.lastname: Guven
authors.forename: Mustafa Hamidullah
authors.initials: MH
authors.lastname: Turkkani
authors.forename: Bulent
authors.initials: B
authors.lastname: Ciftci
authors.forename: Tansu Ulukavak
authors.initials: TU
authors.lastname: Ciftci
authors.forename: Yurdanur
authors.initials: Y
authors.lastname: Erdogan
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D002561:Cerebrovascular Disorders / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012016:Reference Values; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D013223:Statistics as Topic; D014421:Turkey
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein