Selective calcium and calcitriol supplementation guided by early postoperative parathyroid hormone levels was not superior to routine prophylactic supplementation for preventing symptomatic hypocalcemia following total thyroidectomy, according to a multicenter randomized clinical trial of 258 patients.
In the pragmatic diagnostic randomized clinical trial, published in JAMA Otolaryngology–Head & Neck Surgery, adults undergoing total thyroidectomy for benign or malignant disease at 3 tertiary hospitals in Colombia were randomized 1:1 to routine calcium carbonate (1,200 mg every 8 hours) plus calcitriol (0.25 μg every 12 hours) for 15 days, or to selective supplementation based on a 4-hour postoperative parathyroid hormone (PTH) threshold of less than 15 pg/mL. Patients with parathyroid hormone levels of 15 pg/mL or greater received no supplementation.
The primary outcome was symptomatic hypocalcemia within 15 days, assessed using a modified 14-item Hypoparathyroid Patient Questionnaire administered preoperatively, at postoperative day 2, and at day 15.
Symptomatic hypocalcemia occurred in 24 of 258 patients (9%). Rates were 8% in the parathyroid hormone–guided group and 11% in the routine supplementation group. Mean symptom scores at 48 hours and 15 days did not differ between groups.
In the subgroup of 148 patients with complete biochemical data, biochemical hypocalcemia at 15 days occurred in 22% of the parathyroid hormone group and 18% of the routine group. Using the 15 pg/mL threshold, early PTH demonstrated 88% sensitivity and 69% specificity for predicting biochemical hypocalcemia at 2 weeks.
Approximately 43% of patients in the selective group had parathyroid hormone levels less than 15 pg/mL at 4 hours. Despite similar clinical outcomes, postoperative supplementation was required less often with the selective strategy. In the overall cohort, the proportion of patients receiving supplementation was reduced by about 65 percentage points compared with routine therapy, and by about 57 percentage points in the subgroup with complete laboratory follow-up.
Adverse events, including gastrointestinal symptoms, and postoperative complications such as dysphonia, hematoma, and readmission for hypocalcemia, were similar between groups. No cases of acute kidney failure were observed.
Limitations included lack of blinding, modification of the symptom questionnaire without formal psychometric validation in Spanish, interinstitutional variability in parathyroid hormone assays, absence of some hypocalcemia risk variables, and reliance on a subset analysis for biochemical outcomes.
Carlos Garcia-Lozano, MD, of the Head and Neck Service, Department of Surgery, School of Medicine, Universidad de Antioquia, Medellín, Colombia, and colleagues concluded that “selective C+C supplementation guided by postoperative PTH levels was not superior to routine prophylactic C+C for preventing symptomatic hypocalcemia or biochemical hypocalcemia after total thyroidectomy for benign or malignant disease.”
The researchers reported no conflicts of interest.