Evaluation of preoperative procollagen type 1 N-terminal peptide and collagen type 1 C-telopeptide levels in the prediction of postoperative hypocalcemia in patients undergoing parathyroidectomy due to primary hyperparathyroidism.

Purpose: This study is aimed at investigating the role of preoperative procollagen type 1 N-terminal peptide (P1NP) and collagen type 1 C-telopeptide (CTx) levels in predicting the development of postoperative hypocalcemia in primary hyperparathyroidism (PHPT).

Methods: In this prospective observational study, preoperative complaints of patients with primary hyperparathyroidism and their urea, creatinine, glomerular filtration rate (GFR), calcium, albumin, urinary calcium, parathyroid hormone, and bone mineral density (BMD) were recorded. P1NP and CTx levels were analyzed in blood samples taken the day before surgery, and their relationship with calcium levels obtained on the first postoperative day was examined.

Results: The median age was 53 years for patients who developed hypocalcemia and 62 years for those who did not develop hypocalcemia (p = 0.01). The urea, creatinine, and GFR values were determined as 22 mcg/dl, 0.61 mcg/dl, and 105 ml/min, respectively, for the hypocalcemia group (Group 1) and 30.5 mcg/dl, 0.74 mcg/dl, and 90 ml/min, respectively, for the non-hypocalcemia group (Group 2) (p = 0.02, 0.001, and 0.01, respectively). The BMD femur Z-score was - 0.1 in Group 1 and 0.8 in the Group 2 (p = 0.02). The mean CTx values were 4.14 pg/dl and 1.98 pg/dl (p = 0.036), and the mean P1NP values were 252.84 mcg/dl and 269.04 mcg/dl (p = 0.427) for Groups 1 and 2, respectively. According to multivariate analysis, only CTx was a significant independent predictor of hypocalcemia (odds ratio 1.739).

Conclusion: CTx level is a significant factor in predicting the risk of developing early postoperative hypocalcemia in patients scheduled for surgery due to primary hyperparathyroidism.