Mortality Lower With Parathyroidectomy, Despite Lab Values

PTx patients had 15.7% lower odds of premature death.
PTx patients had 15.7% lower odds of premature death.

CHICAGO—Parathyroidectomy (PTx) may confer a survival advantage even if the surgery does not lead to biochemical control of secondary hyperparathyroidism, finds a new Italian study presented at the American Society of Nephrology's 2016 Kidney Week meeting.

Sandro Mazzaferro, MD, and colleagues of the Italian Study Group of Mineral Metabolism in Rome, identified 524 living PTx patients (average age 57.9) and 432 matched control patients from a pool of 12,515 patients visiting 149 hemodialysis centers located across the country. A median of 6 years had elapsed since surgery, which was either subtotal PTx, total PTx, or total PTx with autotransplantation.

At enrollment, PTx patients had lower serum values overall of calcium (8.76 vs 9.05 mg/dL), phosphorus (4.90 vs 5.10 mg/dL), and parathyroid hormone (PTH) (181.9 vs 333.7 pg/mL). Yet a smaller proportion of PTx patients actually achieved KDIGO (Kidney Disease: Improving Global Outcomes) targets compared with controls:

  • Phosphorus 55.3% vs 58.8%
  • Calcium 50.9% vs 57.6
  • PTH 17% vs 35%

The investigators confirmed that PTH levels were more often on target in the control group during the first 2 years of follow up. Still, the odds of death from any cause were 15.7% lower for PTx patients, according to a multivariable analysis.

“PTx associates with lower risk of mortality regardless of achievement of Ca, P, or PTH targets,” Dr Mazzaferro told Renal & Urology News. “Our results suggest that parathyroid surgery, even though invasive for the patient, associates with a uremic condition that is more favorable than occurs with drugs. We should think of PTH as a toxin.”

Patients in the study had been on dialysis for a long time and had received outdated treatment strategies. So new drugs (e.g., non calcium-based binders, calcium-sensing receptor, and vitamin D receptor activators) applied with different strategies (lower targets of calcium and phosphate) should be assessed, Dr Mazzaferro added. In addition, future research should identify which CKD and ESRD patients would benefit most from early surgery.

The study was funded by an unrestricted grant from Amgen.

Reference

  1. Mazzaferro S, the Italian Study Group of Mineral Metabolism. Parathyroidectomy (PTX), KDOQI Targets and Mortality in a Cohort of Italian Dialysis (D) Patients: A Multicenter Observational Study. Presented at: Kidney Week 2016. November 15-20, 2016. Chicago. Abstract FR-PO971.

Click here for more coverage from the American Society of Nephrology's Kidney Week 2016 in Chicago.

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