In the management of patients on dialysis who have secondary hyperparathyroidism (SHPT), uncertainty remains over the optimal parathyroid hormone (PTH) range to target and who should undergo parathyroidectomy (PTx) in the calcimimetics era.
To clarify matters, Wei Ling Lau, MD, Yoshitsugu Obi, MD, PhD, and Kamyar Kalantar-Zadeh, MD, MPH, PhD, published a review article in the Clinical Journal of the American Society of Nephrology. Available evidence suggests benefits from combined use of vitamin D analogs and calcimimetics, they stated. For SHPT refractory to medical therapy, PTx is reasonable in dialysis patients with PTH levels of 600 to 800 pg/mL, or when there is persistent hypercalcemia or hyperphosphatemia or risk for calciphylaxis despite optimized vitamin D and calcimimetic therapy. When PTH levels persist above 800 pg/mL for more than 6 months despite medical therapy, they explained, monoclonal proliferation with nodular hyperplasia has likely occurred in the parathyroid glands, along with decreased expression of vitamin D and calcium-sensing receptors, warranting surgery.
Based on limited evidence, PTx improves survival. Surgery eases hypercalcemia, hyperphosphatemia and tissue calcification, improves bone mineral density, and leads to better health-related quality of life. The choice of surgery depends on individual circumstances. Subtotal PTx is preferable when an adenoma is causing the increase in PTH. Total PTx with autotransplantation is the best option for patients who cannot undergo reoperation. Total PTx without autotransplantation is preferable for younger patients and those with no expectation of a kidney transplant.
The authors emphasized that clinicians should monitor all surgery patients for hungry bone syndrome because it so prevalent. Treatment involves high doses of oral and intravenous calcium along with calcitriol supplementation.
Use of PTx has declined in the United States to approximately 7 per 1000 dialysis patient-years during 2002 to 2011, even while average PTH levels have risen, the authors noted.
“Given favorable long-term outcomes from observational parathyroidectomy cohorts, despite surgical risk and postoperative challenges, it is reasonable to consider parathyroidectomy in more patients with medically refractory secondary hyperparathyroidism,” the authors concluded.
Lau WL, Obi Y, and Kalantar-Zadeh K. Parathyroidectomy in the management of secondary hyperparathyroidism. Clin J Am Soc Nephrol. doi:10.2215/CJN.10390917