The ViKTORIES trial: A randomized, double‐blind, placebo‐controlled trial of vitamin K supplementation to improve vascular health in kidney transplant recipients
What this study found
Vitamin K did not improve vascular stiffness or vascular calcification over 12 months in kidney transplant recipients. For the primary endpoint, ascending aortic distensibility at 12 months was similar between groups, with an adjusted treatment effect of -0.23 (95% CI -0.75 to -0.29; p = .377); the multiple-imputation estimate was -0.19 (-0.71 to -0.32). The vitamin K group changed from 2.7 to 2.5 x10^-3 mmHg^-1, while placebo changed from 2.9 to 2.7 x10^-3 mmHg^-1. The authors concluded that improving vascular health in this population will likely require a multifaceted approach.
- Study & population
- Randomized, double-blind, placebo-controlled trial in adults with a functioning kidney transplant for at least 1 year.
- Intervention
- Oral vitamin K was given as 5 mg menadiol diphosphate three times per week on Monday, Wednesday, and Friday for 12 months.
- Key limitation
- The trial was modest in size, single-center, and limited to 12 months of follow-up, which reduces power to detect smaller or longer-term effects.
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Open PDFOriginal abstract
Premature cardiovascular disease and death with a functioning graft are leading causes of death and graft loss, respectively, in kidney transplant recipients (KTRs). Vascular stiffness and calcification are markers of cardiovascular disease that are prevalent in KTR and associated with subclinical vitamin K deficiency. We performed a single‐center, phase II, parallel‐group, randomized, double‐blind, placebo‐controlled trial (ISRCTN22012044) to test whether vitamin K supplementation reduced vascular stiffness (MRI‐based aortic distensibility) or calcification (coronary artery calcium score on computed tomography) in KTR over 1 year of treatment. The primary outcome was between‐group difference in vascular stiffness (ascending aortic distensibility). KTRs were recruited between September 2017 and June 2018, and randomized 1:1 to vitamin K (menadiol diphosphate 5 mg; n = 45) or placebo (n = 45) thrice weekly. Baseline demographics, clinical history, and immunosuppression regimens were similar between groups. There was no impact of vitamin K on vascular stiffness (treatment effect −0.23 [95% CI −0.75 to 0.29] × 10−3 mmHg−1; p = .377), vascular calcification (treatment effect −141 [95% CI − 320 to 38] units; p = .124), nor any other outcome measure. In this heterogeneous cohort of prevalent KTR, vitamin K supplementation did not reduce vascular stiffness or calcification over 1 year. Improving vascular health in KTR is likely to require a multifaceted approach.