title: Prevalence of vitamin K deficiency in cystic fibrosis.
abstract: BACKGROUND
  Patients with cystic fibrosis (CF) are at risk of developing vitamin K deficiency because of pancreatic insufficiency, hepatobiliary disease, or both.
  
  
  OBJECTIVE
  Our objective was to determine the prevalence of vitamin K deficiency in unsupplemented patients with CF and to identify risk factors that might be associated with the deficiency.
  
  
  METHODS
  Ninety-eight patients with CF-83 who were pancreatic insufficient (age: 15.2 +/- 10.7 y; range: 0.6-45.8 y), 15 who were pancreatic sufficient (age: 26.2 +/- 11.6 y; range: 6.5-45.3 y), and 62 healthy individuals (age: 16.2 +/- 12. 8 y; range: 1-45 y)-were studied prospectively. None had taken vitamin K supplements. Eight pancreatic-insufficient patients had advanced CF-associated liver disease. Plasma prothrombin in vitamin K absence (PIVKA-II) was measured by immunoassay. All control subjects had PIVKA-II concentrations <3 microg/L.
  
  
  RESULTS
  Seventy-eight percent of pancreatic-insufficient patients had PIVKA-II concentrations >/=3 microg/L (22.8 +/- 35.7 microg/L). All patients with CF-associated liver disease had abnormal PIVKA-II concentrations. The mean PIVKA-II concentration of pancreatic-insufficient patients with liver disease was greater than that of those without liver disease (46.6 +/- 65.3 compared with 15. 3 +/- 26.1 microg/L; P < 0.05). Five pancreatic-sufficient patients had mildly elevated PIVKA-II concentrations. Six (7%) pancreatic insufficient patients (3 with CF-associated liver disease) had mildly prolonged prothrombin time but no clinical bleeding. There was no correlation between PIVKA-II concentrations and severity of fat malabsorption or antibiotic use.
  
  
  CONCLUSIONS
  Vitamin K deficiency is common in unsupplemented patients with CF and pancreatic insufficiency and routine supplementation should be considered in all of these patients.
authors.affiliation: Division of Gastroenterology and Nutrition, the Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Rashid
authors.forename: P
authors.initials: P
authors.lastname: Durie
authors.forename: M
authors.initials: M
authors.lastname: Andrew
authors.forename: D
authors.initials: D
authors.lastname: Kalnins
authors.forename: J
authors.initials: J
authors.lastname: Shin
authors.forename: M
authors.initials: M
authors.lastname: Corey
authors.forename: E
authors.initials: E
authors.lastname: Tullis
authors.forename: P B
authors.initials: PB
authors.lastname: Pencharz
mesh_terms: D000293:Adolescent; D000328:Adult; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014813:Vitamin K Deficiency / Q000150:complications / Q000453:epidemiology*