Variations of parathyroid hormone and bone biomarkers are concordant only after a long term follow-up in hemodialyzed patients

Osteocalcin and Abdominal Aortic Calcification in Hemodialysis Patients: An Observational Cross-Sectional Study

OBJECTIVES

To investigate the serum level of osteocalcin (OC), also known as bone Gla protein, in maintenance hemodialysis (MHD) patients and its correlation with abdominal aortic calcification (AAC).

METHODS

From July 2017 to February 2020, we enrolled 108 adult MHD patients. Routine fasting blood laboratory tests were performed before the start of the second hemodialysis in a week. Abdominal aortic calcification score (AACs) was assessed within 1 month. Pearson correlation and Logistic regression were used to analyze the data.

RESULTS

The OC level was 231.56 (25.92,361.33) ng/ml, elevating significantly in this group of MHD patients. It had a positive correlation with serum phosphorus (r = 0.511, P = 0.001), intact parathyroid hormone(iPTH) (r = 0.594, P = 0.0001), fibroblast growth factor 23(FGF23) (r = 0.485, P = 0.003) and a negative correlation with age(r = -0.356, P = 0.039). Based on the AACs, patients were divided into two groups. Serum OC level were higher in patients with AACs≥5 (p=0.032). A multiple logistics regression analysis revealed that age (odds ratio [OR]1.14, P=0.005) and OC(OR=1.10, P=0.008)were risk factors for high AACs(≥5).

CONCLUSION

The study implicated that OC elevated significantly in this group of MHD patients.OC is positively correlated with phosphorus, iPTH, FGF23, and a negative correlation with age. OC was a risk factor for vascular calcification in this study, but this study did not classify osteocalcin as c-OC and unOC. Whether unOC is associated more directly with vascular calcification requires further study.

Bone turnover correlates with bone quantity but not bone microarchitecture in chronic hemodialysis

INTRODUCTION

In chronic hemodialysis, high-turnover bone disease was associated with decreased bone mineral density (BMD), poor bone quality (chemical and structural), and increased fracture risk. Our aim was to correlate bone turnover markers (BTMs) with bone microarchitecture measured by trabecular bone score (TBS) before and after correction for BMD.

MATERIALS AND METHODS

We measured lumbar spine (LS), femoral neck, and 1/3 radius BMD and LS TBS by dual X-ray absorptiometry in 81 patients on permanent hemodialysis. Bone turnover was assessed using serum parathyroid hormone, osteocalcin, C-terminal crosslaps of type 1 collagen, procollagen 1 N-terminal propeptide (P1NP), and alkaline phosphatase (ALP). No patient had any partial or total parathyroidectomy and no previous or current treatment with anti-osteoporotic drugs.

RESULTS

All BTMs correlated significantly with each other. Univariate regressions showed significant negative correlations between BTMs and BMD (best r = - 0.53, between P1NP and 1/3 radius Z-score) or BTMs and TBS (best r = - 0.27, p < 0.05 between ALP and TBS T-score). TBS correlated significantly with BMD at all three sites (best r = 0.5, between LS BMD and TBS T-score). Multivariate regression showed that TBS, crude or adjusted, correlated with LS BMD. No model retained any of the BTMs as independent variables due to the better prediction of BMD and multicollinearity.

CONCLUSION

We showed a progressively impaired bone microarchitecture with increasing bone turnover in chronic hemodialysis. However, this correlation is no longer present when controlling for bone mass. This suggests that impaired bone microarchitecture and increased fracture risk are dependent upon factors other than high bone turnover.

Severe secondary hyperparathyroidism in patients on haemodialysis is associated with a high initial serum parathyroid hormone and beta-CrossLaps level: Results from an incident cohort

BACKGROUND

Secondary hyperparathyroidism (SHPT) is a frequent complication of renal disease and most commonly occurs in patients on haemodialysis (HD) with metabolic, vascular, endocrine, and bone complications. The aim of this study was to analyze the evolution of mineral metabolism parameters during the first 36 months of HD treatment and identify the initial factors associated with severe SHPT.

METHODS

Serum parathyroid hormone (PTH), calcium and phosphate levels were measured monthly; bone-specific alkaline phosphatase (b-ALP) and beta-CrossLaps (CTX) were measured biannually. Severe SHPT was defined as the need for cinacalcet treatment. Patients with less than 24 months of follow-up were excluded.

RESULTS

One hundred thirty-three incident HD patients were included. Baseline mean PTH was 275 ± 210 pg/mL. After an initial drop at the third month (172 ± 133 pg/mL), the serum PTH level progressively increased to the maximum at 36 months (367 ± 254 pg/mL). This initial drop was associated with the initial correction of both hypocalcaemia and hyperphosphataemia. Serum CTX and b-ALP revealed no significant changes over time. Severe SHPT was observed in 18% of patients and was associated with higher mean calcaemia and phosphataemia. In logistic regression, the initial factors associated with the risk of severe SHPT were: female sex, higher baseline PTH and CTX values. A receiver operation characteristic curve analysis identified a cut-off value of >374 pg/mL for baseline PTH and >1.2 μg/L for CTX for increased risk of developing severe SHPT. The relative risk of developing severe SHPT was 3.7 (1.8-7.5, p = 0.002) for high baseline CTX, 4.9 (2.4-9.7, p = 0.001) for high baseline PTH, and 7.7 (3.6-16, p< 0.0001) when both criteria were present.

CONCLUSION

After an initial drop, a progressive increase in the serum PTH level during the first 3 years of HD treatment was observed despite aggressive therapy. High baseline levels of PTH and CTX increased the risk of developing severe SHPT.