Kidney Week

Abstract: FR-PO136

Effect of Active Vitamin D and Calcium-Sensing Receptor Agonists on the Responsiveness of Bone to the Parathyroid Hormone in Hemodialysis Patients

Session Information

• Bone and Mineral Metabolism: Phosphorus, FGF23, Vascular Calcification
  November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Tominaga, Naoto, Kawasaki Municipal Tama Hospital, Kawasaki, Japan

Naoto Tominaga,

• Yonaha, Tomoki, Yonaha Medical Clinic, Ishigaki, Okinawa, Japan

Tomoki Yonaha,

• Yamanouchi, Masayuki, Okinaka Memorial Institute for Medical Research, Tokyo, Japan

Masayuki Yamanouchi,

• Sumi, Hirofumi, Kawasaki Municipal Tama Hospital, Kawasaki, Japan

Hirofumi Sumi,

• Taki, Yasuhiro, Kawasaki Municipal Tama Hospital, Kawasaki, Japan

Yasuhiro Taki,

• Shibagaki, Yugo, St. Marianna University School of Medicine, Kawasaki, Japan

Yugo Shibagaki,

• Shiizaki, Kazuhiro, Jichi Medical University, Shimotsuke, Japan

Kazuhiro Shiizaki,

• Yano, Shozo, Shimane University Faculty of Medicine, Shimane, Japan

Shozo Yano,

Background

Levels of the serum parathyroid hormone (PTH) and serum tartrate-resistant acid phosphatase-5b (TRACP-5b), a bone resorption marker derived from osteoclasts, show a positive correlation. In hemodialysis (HD) patients, however, the responsiveness of bone to the serum PTH level varies widely among individuals, and the serum TRACP-5b level relative to the serum PTH level varies. This study examined factors related to the responsiveness of bone to PTH in HD patients.

Methods

This study of HD patients in Kawasaki Municipal Tama Hospital (Kanagawa, Japan) and Yonaha Medical Clinic (Okinawa, Japan) excluded those with HD for <6 months, a combination of peritoneal dialysis, cancer bone metastases, and myeloma. The TRACP-5b/intact PTH (iPTH) ratio was newly created as an index of responsiveness of bone to PTH, categorized by tertiles of the ratio (low, medium, and high), and a cross-sectional study was conducted. In each analysis, P<0.05 was considered statistically significantly different.

Results

One hundred six patients were analyzed. Age (P=0.010), body mass index (BMI) (P=0.003), use of calcium-sensing receptor (CaSR) agonists (P=0.008), use of active vitamin D (VD) (P=0.012), iPTH level (P=0.0001), 1,25(OH)₂D level (P=0.003), and TRACP-5b level (P=0.0001) were statistically significantly different among the three categories. In the simple linear regression analysis, age (P=0.016), corrected serum calcium level (P=0.007), and ln [1,25(OH)₂D] (P=0.044) showed a statistically significant positive correlation with ln (TRACP-5b/iPTH), whereas BMI (P=0.026), use of CaSR agonists (P=0.001), use of active VD (P=0.009), and serum phosphorus level (P=0.018) showed a statistically significant negative correlation. When conducting multiple linear regression analysis incorporating significant variables in the simple linear regression analysis, a statistically significant negative correlation was shown between the TRACP-5b/iPTH ratio and use of active VD and CaSR agonists.

Conclusion

The administration of active VD or CaSR agonists may reduce the stimulatory effect of PTH on bone resorption in HD patients.