PLASMA VITAMIN-K-1 LEVEL IS DECREASED IN PRIMARY BILIARY-CIRRHOSIS

Objective: To measure directly plasma vitamin K-1 in patients with pri mary biliary cirrhosis (PBC) and to examine the relationship between v itamin K-1 level, prothrombin time, other fat-soluble vitamin levels, and severity of cholestasis. Methods: We directly measured levels of v itamin K-1 (phylloquinone) in the plasma of 77 patients with PBC using reverse-phase high-performance liquid chromatography, along with seru m levels of vitamins A, E, and 25-OH vitamin D, Results: Median plasma vitamin K-1 level was significantly lower in PBC patients compared wi th 255 normal subjects (0.65 nmol/L; range, 0.05-4.13, vs 0.95 nmol/L; range, 0.2-4.92; p < 0.0001), Of 77 PBC patients, 18 (23%) patients h ad levels below the normal range for plasma vitamin K-1 (<0.3 nmol/L), Only 1 of the 18 patients with decreased vitamin K-1 had a prolonged prothrombin time, There was no correlation between vitamin K-1 level a nd prothrombin time in the PBC patients (p = 0.75); there was also no difference in prothrombin time between PBC patients with low vitamin K -1 level and PBC patients with normal vitamin K-1 level (10.3 vs 10.0 seconds; p = 0.28), PBC patients with decreased vitamin K-1 levels had significantly lower vitamin A and vitamin E levels, and significantly higher serum bilirubin levels than those with normal vitamin K-1 leve ls, Conclusion: Decreased plasma vitamin K-1 level is common in PBC, a nd is associated with decreased serum levels of vitamins A and E, Howe ver, the majority of PBC patients with decreased plasma vitamin K-1 le vels have normal prothrombin times, Although the prothrombin time is a n insensitive marker of vitamin K-1 status in PBC patients, clinically important vitamin K deficiency seems uncommon.