Witham MD, Lees JS, White M, et al. - This parallel-group, double-blind, randomized trial was undertaken among individuals aged 18 or older with CKD stage 3b or 4 (eGFR 15–45 ml/min per 1.73 m²), to investigate whether arterial stiffness might be improved with vitamin K supplementation in patients suffering from CKD. Participants were randomized to receive 400 μg oral vitamin K2 or matching placebo once daily for a year. In the modified intention-to-treat analysis, there were 159 randomized patients. According to the findings, no improvement in vascular stiffness or other measures of vascular health was brought about by vitamin K2 supplementation in patients with CKD.