Vitamin K supplementation and arterial calcification in dialysis: results of the double-blind, randomized, placebo-controlled RenaKvit trial

Study answer

What this study found

Vitamin K2 supplementation improved vitamin K status but did not significantly slow arterial calcification over 2 years. In the vitamin K arm, serum MK-7 increased progressively and was 40-fold higher than placebo at year 2, while plasma dp-ucMGP was 40-45% lower than placebo and PIVKA-II was lowered by about 45%. Despite these biomarker effects, carotid-femoral PWV, CAC, CVC, and AAC did not differ significantly versus placebo, and calcification progressed in both groups. The adjusted year 2 between-group difference in cfPWV was 1.1 m/s (95% CI -0.1 to 2.2; P = 0.07).

Study & population

Double-blind, randomized, placebo-controlled trial in adult patients receiving maintenance dialysis at multiple centers in Denmark.

Intervention

Oral vitamin K2 as menaquinone-7 (MK-7), one daily tablet containing 360 mg, taken every morning with some dairy fat for 2 years.

Key limitation

The trial was small and had substantial attrition, with marked loss to follow-up by year 2 and very small analyzable samples for imaging outcomes.

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Original abstract