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Abstract: PO0578

Different PTH Responsiveness and Bone Turnover in Japanese as Compared to European Patients Treated with Hemodialysis

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Evenepoel, Pieter, Katholieke Universiteit Leuven, Leuven, Flanders, Belgium
  • Joergensen, Hanne Skou, Katholieke Universiteit Leuven, Leuven, Belgium
  • Komaba, Hirotaka, Tokai Daigaku, Isehara, Kanagawa, Japan
  • Mazzaferro, Sandro, Universita degli Studi di Roma La Sapienza, Rome, Latium, Italy
  • Vervloet, Marc G., Amsterdam Universitair Medische Centra, Duivendrecht, Noord-Holland, Netherlands
  • Cavalier, Etienne, Universite de Liege, Liege, Belgium
  • Fukagawa, Masafumi, Tokai Daigaku, Isehara, Kanagawa, Japan

Group or Team Name

  • on behalf of the CKD-MBD working group of the JSN, and EUROD, an initiative of the CKD-MBD working group of the ERA-EDTA
Background

Parathyroid hormone (PTH) targets are lower in Japanese compared to European patients on dialysis. Whether this translates to lower bone turnover may depend on PTH responsiveness. This study tested the hypothesis that skeletal PTH responsiveness differs between Japanese and European hemodialysis patients.

Methods

Whole PTH (Roche), bone-specific alkaline phosphatase (BsAP, IDS-iSYS), and tartrate-resistant acid phosphatase type 5b (TRAP5b, IDS-iSYS) were centrally assessed in 378 prevalent hemodialysis patients from Japan and Belgium, matched 1:1 on age, gender, diabetes, and dialysis vintage. Patients with PTH levels at the extremes (<normal range or >15 xUNL) were excluded.

Results

Patients were well matched in age (59±12 yrs), gender (66% male), diabetes (34%), and dialysis vintage (39 [22-63] months). Japanese patients had lower PTH levels (109 vs 161 ρg/mL, p<0.001) and bone turnover markers (BsAP 15.3 vs 24.5 ug/L; TRAP5b 3.35 vs 5.79 U/L, p<0.001 both). Scatterplots and linear regression revealed higher bone turnover markers in European patients for any given level of PTH (Figure). In a multivariable model, Japanese nationality, male gender, higher BMI, and higher PTH were negative predictors of the TRAP5b/PTH ratio (Table).

Conclusion

Skeletal PTH responsiveness is lower in Japanese as compared to European patients on dialysis; thus, differences in PTH sensitivity cannot reconcile the current discrepancies in PTH target range.

Table: Determinants of Ln (TRAP5b/PTH) by multivariable linear regression
 β-coefficientStandard errorp-value
Nationality, Japanese-0.4800.053<0.001
Gender, male-0.1960.0510.003
Body mass index, kg/sqm-0.0330.005<0.001
Ln (1-84) PTH-0.6090.314<0.001

Stepwise selection of variables. Model adjusted R-sq 52%, p<0.001.

Scatterplots of bone turnover markers over PTH

Funding

  • Private Foundation Support