Combined low vitamin D and vitamin K status is associated with greater risk of premature mortality and transplant failure in stable kidney transplant recipients

A.J. van Ballegooijen, J.W.J. Beulens, C.A. Keyzer, G.J. Navis, S.P. Berger, M.H. de Borst, M.G. Vervloet, S.J.L. Bakker

Thursday 15 march 2018

15:15 - 15:20h at Willem Burger Foyer

Categories: Clinical, Session (poster)

Parallel session: Poster session 3: Clinical

Introduction

Renal transplant recipients (RTR) often have nutrient deficiencies, including vitamin D and K. Both vitamin D and K deficiency play a major role in vascular disease, however, the long-term implications of combined vitamin D and K deficiency in RTR is unknown. We prospectively investigated the joint association of low vitamin D and K status with premature mortality and transplant failure in stable RTR.

Methods

We studied 429 RTR, aged 21-80 years, from a single-center with a median of 6.1 years after kidney transplantation. At baseline (2001-2003), vitamin D and functional K status were measured by LC-MS (25-hydroxyvitamin D [25(OH)D]) and immunoassay (dephosphorylated uncarboxylated matrix gla protein [dp-ucMGP]). High dp-ucMGP is indicative for low vitamin K status. Vitamin D and vitamin K were categorized by 25-hydroxyvitamin D <50/≥50 mmol/L and median dp-ucMGP <996/≥996 pmol/L. Vitamin K antagonist users were excluded. We used survival curves and Cox regression analysis until April 1^st 2012 to estimate hazard ratios (HR) and 95% confidence intervals adjusting for potential confounders (demographics, lifestyle, risk factors).

Results

Mean age was 52±12 years at baseline, and 226 RTR (53%) were male. Mean 25(OH)D and median dp-ucMGP concentrations were 52.6±23.1 nmol/L and 996 (interquartile range 732-1473) pmol/L, respectively. Combined low vitamin D and K status was present in 127 RTR (30%). During median 9.8 years follow-up, 113 patients (26%) died and 46 patients (11%) developed transplant failure. Survival curves by vitamin D and K categories differed for premature mortality and graft failure P

Conclusions

Vitamin D and K insufficiency are highly prevalent in stable RTR. Combined low vitamin D and K status is associated with a greater risk of mortality and transplant failure. Future studies should address whether combined vitamin D and K supplementation may lead to improved outcomes after kidney transplantation.