title: Free protein S deficiency in acute ischemic stroke. A case-control study.
abstract: OBJECTIVE
  Deficiency of free protein S, a naturally occurring anticoagulant, may be acquired in the setting of acute illness and increasingly has become recognized as a possible stroke risk factor. We sought to determine whether free protein S deficiency is associated with acute cerebral infarction among older individuals at risk for stroke.
  
  
  METHODS
  Free protein S was measured by Laurell rocket immunoelectrophoresis in 94 adults admitted for acute cerebral infarction and in 94 hospitalized control subjects of similar age, sex, and race. Patients with a history of cerebrovascular disease, acute thrombotic or hematologic diseases, or medical conditions known to cause free protein S deficiency were excluded from the control group.
  
  
  RESULTS
  The percentage of patients with free protein S deficiency (< 20% normal total protein S) was similar in the case and control groups (21% versus 20%, respectively). Among all subjects, free protein S deficiency was more common in blacks than nonblacks (34% versus 13%, p = 0.001). A very low free protein S (< 15% normal total protein S) was more frequent among case patients than control subjects (11% versus 5%), but this trend failed to reach statistical significance.
  
  
  CONCLUSIONS
  Free protein S deficiency is common among hospitalized patients, even in the absence of a recognized predisposing condition. Our findings indicate that acquired deficiency of free protein S is not a major risk factor for ischemic stroke.
authors.affiliation: Department of Neurology, Columbia-Presbyterian Medical Center, New York.
authors.forename: S A
authors.initials: SA
authors.lastname: Mayer
authors.forename: R L
authors.initials: RL
authors.lastname: Sacco
authors.forename: A
authors.initials: A
authors.lastname: Hurlet-Jensen
authors.forename: T
authors.initials: T
authors.lastname: Shi
authors.forename: J P
authors.initials: JP
authors.lastname: Mohr
mesh_terms: D000208:Acute Disease; D000368:Aged; D044383:Black People; D016022:Case-Control Studies; D002544:Cerebral Infarction / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018455:Protein S Deficiency; D044465:White People