Persistent elevation of parathormone levels after surgery for primary hyperparathyroidism

• Main Authors: Sunil K Kota, Siva K Kota, Sruti Jammula, P RK Bhargav, Abhay K Sahoo, Sambit Das, Satish C Talluri, Srikanth Kongara, S V S Krishna, K D Modi
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2020-01-01
• Series: Indian Journal of Endocrinology and Metabolism
• Subjects: normocalcemia; parathormone; parathyroidectomy; primary hyperparathyroidism
• Online Access: http://www.ijem.in/article.asp?issn=2230-8210;year=2020;volume=24;issue=4;spage=366;epage=372;aulast=Kota

Background: Persistent elevation of serum parathyroid hormone (PTH) despite normocalcemia have been documented in 8- 40% of patients after parathyroidectomy. We hereby report our experience from different centers across India to determine clinical significance of postoperatively elevated PTH levels and review relevant literature. Methods: We conducted a retrospective case series study and reviewed all the patients who underwent surgery for primary hyperparathyroidism (PHPT) from April 2010 to January 2020. Results: Total of 201 patients was diagnosed as PHPT. Out of available follow-up data of 180 patients, a total of 54 patients (30%) had persistently elevated PTH (PePTH) at 1 month. Patients with PePTH were older with higher preoperative serum calcium, iPTH, alkaline phosphatase and lower serum phosphate and 25-hydroxy vitamin D3 levels. Creatinine clearance was found to be significantly lower in patients with PePTH. Multiple linear regression analysis revealed that preoperative 25-OH D3 concentration, creatinine clearance and iPTH are the factors influencing persistent elevation of PTH levels. Significantly lower serum calcium and higher alkaline phosphatase levels were observed in PePTH patients with preoperative 25-OH D3 levels <20 ng/mL. Thirty patients at 6 months, 24 patients at 1 year, 18 patients at 2 years and 9 patients at 3 years had eucalcemic PTH elevation. Nine out of 126 (7%) patients with normal initial postoperative calcium and iPTH levels developed PePTH, with none culminating into recurrent hyperparathyroidism. Conclusion: Though the pathogenesis of such a phenomenon still remains to be elucidated, a multifactorial mechanism appears to play a role.