Evaluation for primary hyperparathyroidism after radioactive iodine treatment in patients with Graves' disease. Surgery 2024 Dec;176(6):1623-1626
Date
09/11/2024Pubmed ID
39256098DOI
10.1016/j.surg.2024.07.046Scopus ID
2-s2.0-85203448229 (requires institutional sign-in at Scopus site) 1 CitationAbstract
BACKGROUND: Retrospective studies are conflicting regarding the risk of primary hyperparathyroidism after radioactive iodine treatment. We hypothesized that primary hyperparathyroidism rates are greater after radioactive iodine than after thyroidectomy and that patients with hypercalcemia after treatment for Graves' disease are not adequately evaluated for primary hyperparathyroidism, contributing to underdiagnosis of radioactive iodine-associated primary hyperparathyroidism.
METHODS: This retrospective review considers patients undergoing radioactive iodine or thyroidectomy for Graves' disease at a tertiary referral center between January 1, 2000, and January 31, 2022. Patients were identified using a hospital-based cohort discovery tool; exclusions included history of head/neck radiation, primary hyperparathyroidism/parathyroidectomy, renal dysfunction diagnoses, or treatment with both radioactive iodine and thyroidectomy. Patients with an elevated calcium (>10.2 mg/dL) level measured after treatment were classified as "incomplete workup" (no parathyroid hormone), "likely primary hyperparathyroidism" (parathyroid hormone >40 pg/dL), or "unlikely primary hyperparathyroidism" (parathyroid hormone <40 pg/dL).
RESULTS: Of 900 patients, 468 (52%) had been treated with radioactive iodine and 432 (48%) with thyroidectomy. At a median follow-up of 9.39 years (interquartile range, 5.12-13.25), 25% (n = 224) of patients did not have a serum calcium measured and 52 (8%, n = 676) patients had an elevated calcium level. Hypercalcemia was more common after radioactive iodine (10%) than thyroidectomy (6%, P = .061). Of patients with hypercalcemia, 33 (63%) were "incomplete workup," 5 (10%) were "likely primary hyperparathyroidism," and 14 (27%) were "unlikely primary hyperparathyroidism." There was no difference in primary hyperparathyroidism workup rates between patients treated with radioactive iodine (n = 23) and thyroidectomy (n = 10, P = .389).
CONCLUSIONS: Patients treated with radioactive iodine for Graves' disease may experience an elevated rate of hypercalcemia, but the majority are not adequately evaluated for primary hyperparathyroidism. Patients with a history of radioactive iodine should undergo regular calcium screening and, if elevated, appropriate workup for primary hyperparathyroidism.
Author List
Melin SJH, Park SY, Shaker J, Yen TWF, Evans DB, Wang TS, Dream SAuthors
Douglas B. Evans MD Professor in the Surgery department at Medical College of WisconsinJoseph L. Shaker MD Professor in the Medicine department at Medical College of Wisconsin
Tracy S. Wang MPH, MD Professor in the Surgery department at Medical College of Wisconsin
Tina W F Yen BA, MS, MD Professor in the Surgery department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AdultFemale
Graves Disease
Humans
Hypercalcemia
Hyperparathyroidism, Primary
Iodine Radioisotopes
Male
Middle Aged
Retrospective Studies
Thyroidectomy
