The Value of Postoperative Parathyroid Hormone Levels in Predicting the Need for Long-Term Vitamin D Supplementation after Total Thyroidectomy

• Published in: Annals of surgical oncology Vol. 18; no. 3; pp. 777 - 781
• Main Authors: Wang, Tracy S., Cayo, Ashley K., Wilson, Stuart D., Yen, Tina W. F.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.03.2011; Springer Nature B.V
• Subjects: Adenocarcinoma, Follicular - blood; Adenocarcinoma, Follicular - surgery; Adolescent; Adult; Aged; Aged, 80 and over; Calcium - blood; Carcinoma, Papillary - blood; Carcinoma, Papillary - surgery; Cohort Studies; Dietary Supplements; Endocrine Tumors; Female; Follow-Up Studies; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Oncology; Postoperative Period; Prognosis; Retrospective Studies; Surgery; Surgical Oncology; Thyroid Neoplasms - blood; Thyroid Neoplasms - surgery; Thyroidectomy; Thyroiditis - blood; Thyroiditis - surgery; Vitamin D - blood; Young Adult; Oral Calcium Supplementation; Central Neck Dissection; Postoperative Hypocalcemia; Total Thyroidectomy; Lateral Neck Dissection
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-010-1377-5

Background Few studies have examined the need for vitamin D supplementation after total thyroidectomy. This study examines the role of postoperative day (POD) 1 serum calcium and parathyroid hormone (PTH) levels in predicting the need for long-term vitamin D supplementation after total thyroidectomy. Methods A retrospective, single institutional study of patients who underwent total thyroidectomy between January 2007 and December 2008 was performed. Data collected included extent of surgery, final pathology, postoperative calcium (mg/dl) and PTH (pg/ml) values, and duration of vitamin D supplementation. Patients were divided into 4 groups based on POD1 PTH values: group 1 (<5.0); group 2 (5.0–10); group 3 (10.1–20); and group 4 (>20). Results Of the 104 patients, 26 were in group 1, 12 in group 2, 18 in group 3, and 48 in group 4, with median PTH values of <2.5, 8.2, 14.1, and 30 pg/ml, respectively. All 7 (7%) patients who required vitamin D supplementation >1 month were in group 1. The positive predictive value of POD1 PTH <5.0 in predicting supplementation >1 month was 27% (sensitivity 100%, specificity 80%). Seventy-eight patients had a POD1 PTH level ≥5, and none required vitamin D supplementation >1 month (100% negative predictive value). The positive predictive value of various POD1 calcium thresholds (<7.5, <8.0, and <8.5 mg/dl) was 17, 14, and 15%, respectively. Conclusions Postoperative PTH levels better predict long-term hypocalcemia requiring vitamin D supplementation than serum calcium levels. A PTH level ≥5.0 may identify patients who can be safely discharged without routine vitamin D supplementation.