Tehran University Medical Journal

Background: Hypocalcemia is one of the most prevalent complications following total thyroidectomy. Over recent years, in addition to hormone parathyroid hormone (PTH), vitamin D has been also studied as a factor causing post-total thyroidectomy hypocalcemia. This survey seeks to study the relationship between the serum level of vitamin D before surgery and during post-total thyroidectomy hypocalcemia.

Methods: A group of 57 patients volunteering for total thyroidectomy were studied on Vali-e-Asr Hospital, Tehran, Iran, from March 2013 to March 2015. In all these patients, pre-surgery calcium, vitamin D and parathyroid hormone (PTH) as well as the level of calcium during the post-surgery first two days were measured. Based on objectives of this study, the relationship be-tween pre-surgery vitamin D level and post-surgery hypocalcemia was examined.

Results: The average age of patients participating in the survey was 24.1±13.3. They included 19 women (33.3%) and 38 men, total of 40 patients (70.2%). Their average post-surgery calcium level was 9.2±0.77 milligrams per deciliters (mg/dl) and their average vitamin D content before the surgery was 42±12.1 nanomole per liter (nmol/l). The average calcium level before the surgery and the first post-surgery day were meaningfully different in terms of statistics (P<0.001). In terms of vitamin D, 37 patients (64.9%) had pre-surgery vitamin D deficiency and 20 patients (35.1%) had vitamin D insufficiency. Of 37 patients with pre-surgery vitamin D deficiency, 26 were diagnosed with post-surgery first-day hypocalcemia and of 20 patients with vitamin D insufficiency, 14 suffered post-surgery first-day hypocalcemia. This difference was not statistically meaningful (P>0.001). Of 37 patients with pre-surgery vitamin D deficiency, 31 suffered post-surgery second-day hypocalcemia and of 20 patients with vitamin D insufficiency, 18 suffered second-day hypocalcemia. This difference was not statistically meaningful either (P>0.001).

Conclusion: The current study showed that the serum level of vitamin D before total thyroidectomy does not have any role in the occurrence of post-surgery hypocalcemia which is almost common after this type of surgery.