Endocrine Abstracts

Background: Hypoparathyroidism is a rare endocrine disease with low calcium and insufficient parathyroid hormone levels. In most cases it is caused by thyroid surgery. The objective of this retrospective cohort study was to evaluate if the typical therapy regimens of postsurgical hypoparathyroidism with calcitriol have a negative effect on renal function.

Methods: We performed a chart analysis of patients that were seen in a tertiary care hospital in Brussels, Belgium. A total of 101 patients were identified as patients with permanent post-surgical hypoparathyroidism, based on the hospital records of patients who underwent a total thyroidectomy between 1996 and 2016, while still being treated with calcitriol. Patients with pre-existing renal insufficiency and/or active malignancy were excluded. The cohort was predominantly female of Caucasian origin. Kidney function was evaluated before and after surgery (with a maximum follow-up of 12 years), using the CKD-EPI equation.

Results: A multivariate linear regression model was used to correlate kidney function decline with the duration of calcitriol therapy, while accounting for the mean calcium-phosphate product and age. We found a statistically significant (P=0.027) relation between the duration of calcitriol treatment and renal function decline at a rate of 1.06 ml/min/1.73 m² per year of calcitriol therapy.

Conclusions: Renal abnormalities are frequent finding in patients with hypoparathyroidism. Our study, although being retrospective, is the first one to demonstrate a relationship between the duration of calcitriol therapy and progressive renal insufficiency.