FP627POOR VITAMIN K STATUS ASSOCIATES WITH LOW AREAL BONE MINERAL DENSITY AND PREDICTS FRACTURES IN DE NOVO RENAL TRANSPLANT RECIPIENTS

Abstract

Introduction and Aims: Vitamin Kdeficiency isprevalent among patients with end stage renal disease. A poor vitamin K status associates with accelerated vascular calcification. Preliminary data indicate that poor vitamin K status may compromise bone health as well and that increased inflammation may be in the causal pathway. We inves-tigated the association between vitamin K status, inflammation, bone mineral density and incident clinical fractures in a cohort of patients with ESRD, referred for single kidney transplantation. Methods: Parameters of mineral metabolism (including biointact PTH and FGF23, sclerostin, calcidiol, calcitriol), inflammatory (CRP and il6), osteoprotegerin, bone turnover markers (P1NP, BsAP, and TRAP5B) and desphosphorylated-uncarboxylated Matrix GLA Protein (dp-ucMGP), were assessed on blood samples collected immediately prior to kidney transplantation in 518 patients. Areal bone mineral density (aBMD) was measured at lumbar spine and femoral neck by dual energy X-ray absorpti-ometry within 14 days posttransplant. Results: Poor vitamin K status, definedby dp-ucMGP >500 nmol/L, was highly prevalent (90%). High dp-ucMGP levels independently associated with elevated inflammatory markers and low aBMD. No associations were observed between vitamin K status and bone turnover markers. During a median follow-up of 5.1 years, 33 patients sustained a fragility fractures. In multivariable logistic regression analysis, a high dp-ucMGP and a history of fracture were identified as predictors of incident fragility fractures, independent of inflammation, osteoprotegerin and classical determinants including femoral neck aBMD, age and gender. Conclusions: In conclusion, poor vitamin K status associates with inflammation and low areal bone mineral density and predicts fractures in de novo renal transplant recipients. FP627A SERUM SCLEROSTIN LEVEL IS POSITIVELY ASSOCIATED BONE MINERAL DENSITY IN HEMODIALYSIS PATIENTS Ru-Jiang Syu1, Chih-Hsien Wang1, Yu-Li Lin1, Chiu-Huang Kuo1, Yu-Hsien Lai1, Bang-Gee Hsu11Division of Nephrology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan Introduction and Aims:Sclerostin inhibitionof Wnt/b catenin signaling pathway leads to decreased bone formation due to impaired osteoblastogenesis and decreased osteoblast survival. As a Wnt signaling pathway inhibitor, it is interesting to investigate whether sclerostin or dickkopf-1 (DKK1) level is correlated with bone mineral density (BMD) in hemodialysis (HD) patients. Methods: Blood samples were obtained from 75 HDpatients. BMD was measured by dual energy X-ray absorptiometry of the lumbar vertebrae (L2-L4). Serum sclerostin and DKK1 concentrations were determined using a commercially available enzyme-linked immunosorbent assays. Results: Ten (13.3%) HD patients had osteoporosis, 20 patients (26.7%) had osteo-penia, and 45 patients had normal BMD. Advanced age (P = 0.008), decreased height (P < 0.001), body weight (P < 0.001), body mass index (BMI, P = 0.0012), waist circumference (P = 0.001), was associated, while increase alkaline phosphatase (ALP, P = 0.019), urea reduction rate (URR, P = 0.006), fractional clearance index for urea (Kt/V, P = 0.008), sclerostin level (P < 0.001), and female HD patients (P = 0.001) was associated with lower lumbar T-scores. Multivariate forward stepwise linear regression analysis with adjustment for the significant variables indicated that low serum level of sclerostin (b =-0.546, adjusted R2 change = 0.454; P < 0.001), female HD patients (b =-0.288, adjusted R2 change = 0.072; P = 0.0018), and advanced age (b =-0.216, adjusted R2 change = 0.041; P = 0.007) were significantly and independently associated with lumbar BMD among theHD patients. Conclusions: In this study, advanced age or female gender is associated with poor BMD, while serum sclerostin level, but not DKK1, is negatively associated with BMD in HD patients.