title: Severity of obstructive sleep apnea is associated with elevated plasma fibrinogen in otherwise healthy patients.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) has been implicated in both cardiovascular and cerebrovascular diseases. Systemic inflammation and coagulation may be related to cardiovascular pathophysiology in patients with OSA. Fibrinogen is a major coagulation protein associated with inflammation, and long-term elevated plasma fibrinogen is associated with an increased risk of major cardiovascular diseases. We assessed whether severity of OSA is associated with levels of fibrinogen in newly diagnosed, untreated, and otherwise healthy OSA patients.
  
  
  METHODS
  We studied 36 men with OSA and 18 male control subjects (apnea-hypopnea index [AHI]<5 events/h). OSA patients were divided into mild (AHI≥5<15 events/h) and severe (AHI≥15 events/h) OSA groups. Morning fibrinogen levels in OSA patients were compared to those in control subjects of similar age, body mass index, blood pressure, smoking habits, and alcohol consumption.
  
  
  RESULTS
  Fibrinogen levels were significantly elevated in patients with severe OSA compared to both control (P=0.003) and mild OSA (P=0.02) subjects after adjustment for covariates. However, there were no significant differences in fibrinogen levels between mild OSA and control subjects. Fibrinogen levels were directly related to AHI and arousal index and inversely related to mean and lowest oxygen saturation during sleep.
  
  
  CONCLUSIONS
  Severity of OSA was associated with increased fibrinogen level independent of other factors, suggesting that apneic events and oxygen desaturation during sleep are mechanisms for increased fibrinogen levels in patients with OSA.
authors: Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA, Abu.Shamsuzzaman@CCHMC.ORG.
authors: Abu
authors: A
authors: Shamsuzzaman
authors: Raouf S
authors: RS
authors: Amin
authors: Andrew D
authors: AD
authors: Calvin
authors: Diane
authors: D
authors: Davison
authors: Virend K
authors: VK
authors: Somers
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood / Q000175:diagnosis; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000145:classification / Q000175:diagnosis*
chemical_list: D005340:Fibrinogen