Off-Target CKD-MBD Biomarkers Prognostic for Adverse Outcomes

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Dialysis facilities with the least control of PTH, Ca, and P had the greatest risks.
Dialysis facilities with the least control of PTH, Ca, and P had the greatest risks.

Dialysis facilities in which greater proportions of patients do not have biochemical control of chronic kidney disease-mineral and bone disorder (CKD-MBD) are more likely to have patients who experience adverse outcomes, including the need for parathyroidectomy.

In a facility-level study, Geoffrey A. Block, MD, of Denver Nephrology in Denver, Colorado, and colleagues ranked dialysis centers by the percentage of patients with out-of-target and above-target values for at least 2 of 3 biomarkers: parathyroid hormone (PTH), calcium (Ca), and phosphate (P). Target ranges were defined as PTH 150–600 pg/mL; Ca 8.4–10.2 mg/dL; and P 3.5–5.5 mg/dL. The cohort consisted of 39,085 hemodialysis patients receiving care at 1298 DaVita dialysis facilities from September 2009 to December 2010. The researchers divided facilities into quintiles based on percentage of patients with out-of-target and above-target values.

Results showed that facilities in the highest quintile of patients with out-of-target values (24.5% or higher) and above-target values (11.1% or higher) had 7% and 12% increased risks, respectively, for the composite outcome of cardiovascular hospitalization or death compared with facilities in the lowest quintile of out-of-target and above-target values. The investigators found no greater risks for death alone.

In addition, patients at facilities in quintiles 3, 4, and 5 of out-of-target patients had a 2.0, 2.2, and 2.7 times increased risk of undergoing parathyroidectomy, respectively, compared with those at facilities in quintile 1. Patients at facilities in quintiles 3, 4, and 5 of above-target patients had a 4.0, 5.0, and 4.3 times increased risk of undergoing the surgery.

“The results of this study extend previous patient-level analyses showing that two or more of the three biochemical hallmarks of CKD-MBD, PTH, calcium, and phosphate, out of or above the target ranges established by KDOQI or Kidney Disease: Improving Global Outcomes (KDIGO) strongly predicts the risk of major clinical outcomes, independent of case-mix and baseline comorbidity,” Dr Block and colleagues wrote in BMC Nephrology. The investigators performed a sensitivity analysis using PTH 150 to 300 pg/mL and found similar results.

Managing secondary hyperparathyroidism and CKD-MBD is complex with therapy to lower one biomarker affecting another. Previous, patient-level studies have found the combination of the 3 CKD-MBD biomarkers prognostic.

According to the investigators, it is important to determine which therapeutic approaches provide the most biochemical control of all 3 biomarkers with the least risks to safety. “Clinical trials randomizing patients to different treatment protocols would provide the most reliable evidence to address those questions.”

The study was funded by Amgen Inc.

Reference

1. Block GA, Yusuf AA, Danese MD, et al. Facility-level CKD-MBD composite score and risk of adverse clinical outcomes among patients on hemodialysis. BMC Neph. doi: 10.1186/s12882-016-0382-8.

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