PracticeUpdate: Diabetes

AACE 2018 21

PatientsWith LowPTH and CalciumLevels After Total Thyroidectomy at Higher Risk for Developing Hypocalcemia and Permanent Hypoparathyroidism Testing more accurately predicts patients at risk for permanent hypoparathyroidism and allows proper follow-up management P reoperative and postoperative par- athyroid hormone (PTH), as well as calcium levels, should be obtained

from individuals who have undergone a total thyroidectomy in order to assist in predicting who is at risk for developing permanent hypoparathyroidism (PHypoP) and to effectively manage individuals post-surgery. " These higher-risk individuals should be discharged on supplementation. It also helps a clinician not to overprescribe active vitamin D supplements, which can lead to hypercalcemia. " “Our project is important because it helps identify individuals at risk for hypocalcemia and its complications after a total thyroidec- tomy surgery,” Steven L. Brown, MD, who is completing his endocrinology fellowship at the University of Arizona College of Med- icine, Phoenix Campus, and working with the Phoenix VA Health Care System, told Elsevier’s PracticeUpdate . Total thyroidectomy surgeries are being performed more frequently, and postop- erative hypocalcemia is the most common complication from this surgery. Accurately predicting individuals at risk for PHypoP could enable early discharge and appro- priate follow-up and management following the procedure. Findings from the retrospective study con- ducted by Dr. Brown and his colleagues, Predictors of Permanent Hypoparathy- roidism After Total Thyroidectomy in a Single Tertiary Institution, highlight the need to draw both preoperative PTH and calcium, among other labs. “Using these values, we can better predict individuals who need supplementation of the active form of vitamin D and calcium upon dis- charge,” said Dr. Brown. “Predicting these individuals can be difficult, as hypocalce- mia can occur up to 72 hours after surgery.”

Although risk factors for developing hypoparathyroidism have been studied, they are not clearly defined. The research team analyzed data from 176 participants who were divided into 1 of 4 groups: (1) low PTH, low calcium; (2) low PTH, normal cal- cium; (3) normal PTH, low calcium; and (4) normal PTH, normal calcium. PHypoP was defined as individuals with persistently low PTH levels (iPTH < 12 pg/mL), low calcium levels (serum calcium < 8.0 mg/dL), and/ or requiring calcitriol to maintain a normal calcium level for more than 6 months after their total thyroidectomy. Slightly more than 17% of participants in the study developed PHypoP, but this group did not differ from the non-PHypoP group in terms of age, sex, or race. However, the researchers found a significant drop in PTH (69.7% vs 29.7%, P = .016) and in calcium (17.8 % vs 14.3%, P = .042) after surgery in the PHypoP versus non-PHypoP groups. Additionally, a significantly higher percent- age of Group 1 that is, those with both low

PTH and low calcium, developed PHypoP (30.3%, P = .0007) as compared with 19.4% in Group 3, 10.0% in Group 2, and 2.0% in Group 4. The odds ratio of Group 1 devel- oping PHypoP was 4.3 (95% CI = 1.9–9.9) compared to the other groups. On the other hand, preoperative calcium, PTH, and vitamin D levels did not predict PHypoP. “When individuals have both a low PTH and low calcium level postoperatively, a clini- cian should be aware that this individual is at higher risk for developing hypocalcemia and permanent hypoparathyroidism,” said Dr. Brown. “These higher-risk individuals should be discharged on supplementation. It also helps a clinician not to overprescribe active vitamin D supplements, which can lead to hypercalcemia.” “We need to establish protocols in this area,” he added, “so clinicians are treat- ing individuals according to an established guideline.” www.practiceupdate.com/c/68810

VOL. 2 • NO. 3 • 2018