Increased undercarboxylated osteocalcin/intact osteocalcin ratio in patients undergoing hemodialysis.
Serum undercarboxylated osteocalcin (ucOC)/intact osteocalcin (iOC) ratio increased >1.0 in the patients undergoing hemodialysis, particularly in those with high bone turnover state. Consequently, serum ucOC/iOC ratio might lose its significance as a bone metabolic marker to indicate vitamin K deficiency in hemodialysis patients.


BACKGROUND
Serum intact osteocalcin (iOC), undercarboxylated OC (ucOC), and the ucOC/iOC ratio are considered clinically relevant indices in pre-dialysis chronic kidney disease (CKD) and hemodialysis (HD) patients, despite their accumulation in uremic serum.


METHODS
Serum iOC and ucOC were measured along with serum intact parathyroid hormone (iPTH), bone alkaline phosphatase (BAP), and tartrate-resistant acid phosphatase (TRACP)-5b in 89 pre-dialysis CKD and 189 HD patients.


RESULTS
Serum iOC and ucOC showed significantly negative correlations with estimated glomerular filtration rate in pre-dialysis CKD patients, although serum ucOC/iOC ratio did not correlate. Serum ucOC was significantly greater in HD patients than in pre-dialysis CKD patients, while serum iOC did not differ significantly, resulting in serum ucOC/iOC ratio >1.0 in 135 (71.4%) out of 189 HD patients. HD patients with high serum ucOC/iOC ratio (>1.0) had a significantly younger age and significantly higher values of body mass index, serum creatinine, albumin, phosphate, iPTH, and TRACP-5b than those with low ucOC/iOC ratio (≤ 1.0). The baseline iPTH and P1NP correlated with the changes of the ucOC/iOC ratio during the 2 days of the inter-dialytic period. Multivariate analysis showed that log [ucOC/iOC] in HD patients was significantly associated with log [iPTH], log [BAP], or log [TRACP-5b].


CONCLUSIONS
Serum ucOC/iOC ratio >1.0 was observed in as high as 71.4% of HD patients, preferentially with high bone turnover state, in comparison with pre-dialysis CKD patients. These data suggested that serum ucOC/iOC ratio might lose its significance as a bone metabolic marker to indicate vitamin K deficiency in HD patients.
Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan.
Y
Y
Nagata
M
M
Inaba
Y
Y
Imanishi
H
H
Okazaki
S
S
Yamada
K
K
Mori
S
S
Shoji
H
H
Koyama
S
S
Okuno
D000135:Acid Phosphatase / Q000097:blood; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D016723:Bone Remodeling / Q000502:physiology*; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000628:therapy; D012307:Risk Factors; D000071681:Tartrate-Resistant Acid Phosphatase; D016896:Treatment Outcome; D014813:Vitamin K Deficiency / Q000097:blood
D015415:Biomarkers; D007527:Isoenzymes; D010281:Parathyroid Hormone; D015675:Osteocalcin; D000469:Alkaline Phosphatase; C000605510:ACP5 protein, human; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase