MO903THE ASSOCIATION BETWEEN VITAMIN K, CALCIUM, PHOSPHORUS LEVELS AND NUTRITIONAL STATUS IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Vascular calcification is highly prevalent in dialysis patients. The most common postulated cause, apart from calcium and phosphorus disorders, is sub-clinical vitamin K deficiency. It results in the failure of the GLA-matrix protein (MGP) to undergo carboxylation. The lack of functional carboxylated MGP may contribute to increased vascular calcification. Aim: We assessed the relationships between vitamin K, MGP, calcium, phosphorus levels and nutritional status in hemodialysis patients. Method The study included 58 hemodialysis patients in stable clinical condition (mean age 64.1 ± 15.6 yr) . We determined plasma levels of: vitamin K1 and K2 (LC-MS method), GLA -matrix protein (ucMGP and cMGP), osteocalcin (ELISA methods), parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), CRP and routine biochemistry. Echocardiography was performed and BMI was calculated. Nutritional status was assessed by SGA and s-albumin – malnutrition was diagnosed based SGA ≤5 and s-albumin ≤ 38g/l. FFQ-6 was used to dietary assessment. Patients with HPT (n=17; 32%) were treated by active vitamin D/paricalcitrol and calcium carbconicum. Results Malnourished patients (n=11; 20%) presented statistically significantly higher CRP, age and lower phosphorus, iPTH, BUN, creatinine, cholesterol and potassium. Also, malnourished patients presented significantly higher ucMGP and lower cMGP and lower both vitamin K forms in comparison to well-nourished (ucMGP 18.9 vs 13.2 ng/dl; p=0.0005; cMGP 150.1 vs 332.4 ng/dl; p=0.0002). Diet in both groups malnourished and well-nourished not differ significantly, though malnourished patients ate less amount of nutrients. Additionally, phosphorus level positively correlated with Kt/V, SGA and vitamin K2 (R Spearman =- 0.3;p=0.01,R Spearman = 0.4;p=0.05;R Spearman = 0.3; p=0.001, respectively). Conclusion Vitamin K deficiency, as expressed by high ucMGP levels is associated with nutritional status. Low albumin and chronic inflammation might increase risk of calcification in spite relatively low iPTH and phosphorus levels.