Parathyroid gland volume and treatment resistance in patients with secondary hyperparathyroidism: a 4-year retrospective cohort study.

Abstract

Background: The role of parathyroid gland (PTG) ultrasonography in the management of secondary hyperparathyroidism after the introduction of calcimimetics remains unclear. Recent investigations have prompted renewed interest in the use of PTG ultrasonography for assessing treatment resistance to calcimimetics and determining the optimal timing for surgical intervention. This study aimed to explore the hypothesis that the PTG volume correlates with the calcimimetic dose.

Methods: We retrospectively observed outpatients undergoing haemodialysis at baseline and a 4-year follow-up. PTG volume was measured using ultrasonography between January and December 2017 and January and December 2021. We examined the association between baseline PTG volume and calcimimetic doses after 4 years.

Results: Of the 121 patients {median age 64 years [interquartile range (IQR) 54-72]}, 71 had PTG nodules on ultrasonography and the median total PTG volume was 34 mm³ (IQR 0-178). In the short dialysis vintage group, baseline parathyroid hormone levels tended to correlate with baseline calcimimetic doses; however, this trend was not observed in the extended dialysis vintage group. Baseline PTG volume correlated with the cinacalcet-equivalent calcimimetic dose (correlation coefficient 0.46; P < .001) after 4 years. The calcimimetic dose in the group with an estimated PTG volume >500 mm³ was ≈80 mg/day higher than that in the non-PTG nodule group after 4 years. In multivariate linear regression analysis, PTG volume >500 mm³ was associated with a high calcimimetic dose at 4 years in all analysis models.

Conclusions: Assessing PTG volume using ultrasonography may help predict high calcimimetic doses.