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Abstract: PO0350

PTH 1-84 and Bone Alkaline Phosphatase Are Independently Associated with Mortality, Whereas FGF-23 Predicts Dialysis Initiation in CKD Patients

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Titan, Silvia M., Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Bensenor, Isabela M., Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Lotufo, Paulo, Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Moyses, Rosa M.A., Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil
Background

Despite the fact that CKD-MBD is a risk factor for CKD morbidity and mortality, the results of studies regarding the role of individual biomarkers are variable. In addition, dimensionality reduction techniques have not been applied in CKD-MBD. The aim of our study was to evaluate a panel of CKD-MBD biomarkers, namely Ca, P, PTH 1-84, FGF-23, 25-vitamin D, 1.25-vitamin D, bone alkaline phosphatase (BAP) and sclerostin, individually and collectively in relation to death and KRT.

Methods

Events of death and KRT in 454 participants of the Progredir Cohort (Sao Paulo, Brazil) with predominantly CKD G3 and G4 were ascertained after a median follow-up of 6 years. Those with missing values were excluded (n=25) and 4 were lost to follow-up. The association of individual CKD-MBD parameters (DiaSorin® assays) and factors derived from factorial analysis was evaluated through Cox and Competitive Risk models (R package “cmprsk”).

Results

Mean age was 68(12)y, mean eGFR was 38(15) mL/min/1.73m2, 63% were male and 56% diabetic. In univariable analysis, sclerostin, BAP, PTH, and factor 1 were associated with death and 1.25vitD, sclerostin, BAP, FGF-23, PTH, Ca, P, and factor 1 were associated with KRT. After adjustments, BAP, PTH, and factor 1 remained associated with death, and FGF-23 remained associated with KRT (Table). The addition of BAP and PTH (with interaction) to a reference model significantly improved the model fit for death (p=0.01). The addition of FGF-23 with interaction with P significantly improved the model fit for KRT (p=0.0046).

Conclusion

PTH and BAP are positively associated with death and improved its prediction model. This finding suggests that BAP could be reflecting not only bone turnover but also vascular calcification. FGF-23 is associated with the risk of KRT, showing interaction with P. Factorial analysis was helpful in identifying factors significantly associated with events but did not improve prediction.

 UnadjustedModel 1Model 2
 HR (95%CI)pHR (95%CI)pHR (95%CI)p
Death (n=184)
BAP (microg/L)1.01 (1.00 to 1.02)0.011.01 (1.00 to 1.02)0.0041.01 (1.00 to 1.02)0.01
whole PTH (per 10, pg/mL)1.04 (1.01 to 1.07)0.011.05 (1.01 to 1.08)0.011.05 (1.01 to 1.09)0.01
Factor 11.20 (1.08 to 1.33)0.00041.33 (1.15 to 1.52)<0.00011.25 (1.07 to 1.46)0.004
KRT (n=61)
FGF-23 (per 10, pg/mL)1.02 (1.01 to 1.02)
<0.0001
1.01 (1.001 to 1.01)
0.02
1.005 (1.00 to 1.01)
0.05
Serum phosphorus (mg/dL)3.53 (2.53 to 4.90)
<0.0001
1.63 (1.06 to 2.51)
0.03
1.40 (0.91 to 2.17)
0.13

Model 1: adj. age, sex, eGFR; model 2: same as 1 + SBP, DM, MI, AUC, smoking.

Funding

  • Government Support - Non-U.S.