Prevalence of vitamin K deficiency in cystic fibrosis

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. Design: 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 mu g/L. Results: Seventy-eight percent of pancreatic-insufficient patients had PIVKA-II concentrations greater than or equal to 3 mu g/L (22.8 +/- 35.7 mu g/L). All patients with CF-associated liver disease had abnormal PIVKB-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 mu g/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. Then 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.