Prevalence of hyperthyroidism with hypercalcemia in Xindu district and the efficacy of vitamin D3 treatment in these patients: a randomized trial.

BACKGROUND

This trial aimed to analyze the relationship between hyperthyroidism and the morbidity rate of hypercalcemia in the Xindu district, Chengdu, Sichuan province. We observed the level of serum calcium, the bone metabolic and thyroid autoimmune-related antibodies index during vitamin D3 treatment combined with traditional antithyroid drugs (ATD).

METHODS

Our research included hyperthyroid patients with a first-time diagnosis of Graves diseases (GD) combined with hypercalcemia on the basis of conventional anti-hyperthyroidism therapy, which were randomized into a vitamin D3 group (vitamin D3, 800-1,200 IU/day) and an ATD group (methimazole, 15-30 mg/day). All hyperthyroidism patients with hypercalcemia were analyzed, and changes in serum calcium (Ca2+), parathyroid hormone (PTH), thyroid function, thyroid autoimmune-related antibodies, and 25-dihydroxyvitamin D (25-OHVit D) levels during treatment of thyrotoxicosis with added vitamin D3 were explored.

RESULTS

In total, 184 patients with hyperthyroidism were observed, including 36 (19.57%) patients associated with hypercalcemia, with an age of onset of (56.39±5.80) years old. Twelve (6.52%) of these 36 cases reported digestive symptoms as the first manifestation, and four (2.17%) patients presented with a hypercalcemia crisis as the first manifestation. Serum Ca2+, free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin hormone receptor antibody (TRAb) levels increased in patients with hypercalcemia. Following the addition of vitamin D3 treatment, serum Ca2+, FT3, FT4, and TRAb levels were significantly decreased relative to the ATD group, while the thyroid-stimulating hormone (TSH), PTH, and 25-OHVit D levels were normalized.

CONCLUSIONS

Our study highlighted the importance of taking functional digestive disturbance into consideration in hyperthyroidism diagnosis, even in the absence of the typical symptoms. The level of thyroid related antibodies, thyroid function, and bone metabolism in hyperthyroidism patients combined with hypercalcemia could be improved by vitamin D3 adjuvant therapy.

TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2100047870.