Patients with secondary hyperparathyroidism (SHPT) who are resistant to calcimimetic therapy and subsequently undergo parathyroidectomy (PTx) experience no worse outcomes than patients who undergo PTx without having received preoperative calcimimetic treatment, a new study finds.

Investigators led by Manabu Okada, MD, PhD, of Nagoya Daini Red Cross Hospital in Nagoya, Japan, studied perioperative outcomes among187 patients with no history of calcimimetic treatment (NCMT group) and 186 patients resistant to calcimimetic treatment (RCMT group).

PTx is generally recommended for patients with intact parathyroid hormone levels of 500 pg/mL or more, hyperphosphatemia, or hypercalcemia refractory to medical treatment. Surgery is also recommended forpatients with severe osteopenia, pathological fracture, renal stones, parathyroid gland diameter exceeding 10 mm, and severe SHPT-related symptoms.

No significant difference was observed in the success rate of PTx (90.9% NCMT vs 91.4% RCMT), Dr Okada’s team reported in Therapeutic Apheresis and Dialysis. Operative time was significantly longer in the RCMT group than in the NCMT group (180 vs 158 minutes; P <.001), but the difference diminished once enlargement of the parathyroid glands was taken into account. The RCMT group had heavier parathyroid glands (median 1735 mg RMCT vs 1140 mg NCMT; P <.001) and higher rates of fibrous degeneration (29.6% vs 11.8%; P <.001), cystic degeneration (21.0% vs 4.8%; P <.001), hemorrhage/hemosiderin deposition (16.1 vs 7.0; P =.006), and severe adhesion with the thyroid (10.8% vs 2.7%; P =.002).


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There were no differences between groups in the rates of major complications, such as recurrent laryngeal nerve injury, however.

“Taken together, these observations suggest that the resistance to high-dose calcimimetic treatment is associated with accelerated progression of parathyroid hyperplasia,” Dr Okada’s team stated.

They also observed that “operative time could be elongated because of greater enlargement of the parathyroid glands, but the success rate of parathyroidectomy or the incidence rate of perioperative complications are comparable to those of patients with secondary hyperparathyroidism without preoperative calcimimetic treatment.”

Reference

Okada M, Tominaga Y, Ichimori T, Tomosugi T, Hiramitsu T, Tsuzuki T. Surgical outcomes of parathyroidectomy for secondary hyperparathyroidism resistant to calcimimetic treatment: A retrospective single-center cohort study. Ther Apher Dial. doi:10.1111/1744-9987.13553