Suboptimal vitamin K status and its risk factors in a population of Chinese chronic haemodialysis patients.
OBJECTIVE
Vitamin K deficiency is known to be common in haemodialysis patients and associates with adverse outcomes in this population, particularly vascular calcification. We aimed to investigate the vitamin K status in a population of Chinese haemodialysis (HD) patients.


METHODS
We collected demographic and biochemical data from a population of maintenance HD (MHD) patients in our unit and a control group composed of healthy subjects from our outpatient clinic. Fasting serum samples from all subjects were collected for the measurement of known vitamin K-dependent proteins i.e. matrix Gla protein (MGP), osteocalcin (OC) and uncarboxylated osteocalcin (ucOC). We also quantified the fraction of ucOC to total OC (%ucOC). Differences of these parameters between groups were analyzed and risk factors of vitamin K deficiency based on the definition as per %ucOC were investigated.


RESULTS
We enrolled 93 MHD patients as a test group and 93 healthy subjects as a control group. There was no significant difference in MGP between groups (4.0 ± 2.8 pg/mL in MHD vs 4.2 ± 1.2 pg/mL in control; P = 0.676). Mean %ucOC was significantly greater in the MHD patients as compared to control subjects (76.4 ± 20.0% in MHD vs 48.56 ± 15.5%; P < 0.001). Time on dialysis and low-density lipoprotein cholesterol level appeared to be indicators of vitamin K deficiency, with the former being an independent risk factor.


CONCLUSIONS
Defining Vitamin K deficiency by %ucOC, suboptimal vitamin K levels appear common in Chinese MHD patients. Time on dialysis and LDL cholesterol level predict vitamin K deficiency.
Nephrology Division, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China.|Nephrology Division, Affiliated Medical School of University of Electronic Science and Technology, Chengdu, China.
Yunlin
Y
Feng
Department of Nephrology, 452nd Hospital of Chinese People's Liberation Army, Chengdu, China.
Yizhe
Y
Ruan
Nephrology Division, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China.|Nephrology Division, Affiliated Medical School of University of Electronic Science and Technology, Chengdu, China.
Qiang
Q
He
Nephrology Division, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China.|Nephrology Division, Affiliated Medical School of University of Electronic Science and Technology, Chengdu, China.
Wensong
W
Zhang
Nephrology Division, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China.|Nephrology Division, Affiliated Medical School of University of Electronic Science and Technology, Chengdu, China.
Li
L
Wang
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002135:Calcium-Binding Proteins / Q000097:blood; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D008078:Cholesterol, LDL / Q000097:blood; D003430:Cross-Sectional Studies; D016326:Extracellular Matrix Proteins / Q000097:blood; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects*; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014813:Vitamin K Deficiency / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D000097568:Matrix Gla Protein
D015415:Biomarkers; D002135:Calcium-Binding Proteins; D008078:Cholesterol, LDL; D016326:Extracellular Matrix Proteins; D015675:Osteocalcin; D000097568:Matrix Gla Protein
carboxylation; haemodialysis; osteocalcin; risk factor; vitamin K deficiency