Endocrine Abstracts

Background

Parathyroidectomy (PTE) is the basic treatment for symptomatic primary hyperparathyroidism (PHPT). It is also recommended for some asymptomatic patients. However, PTE can be followed by some complications such as postoperative hypocalcemia.

Aim

To evaluate association of demographic, clinical, laboratory factors, preoperative cholecalciferol supplementation and hypocalcemia after PTE in patients with PHPT.

Methods

478 patients with PHPT were included in retrospective study, 256 of them had postoperative hypocalcemia (group 1) and 222 hadn’t (group 2). The data were obtained from the PHPT registry and the qMS medical information system. The demographic, clinical and laboratory features were compared between groups using Mann-Whitney and Chi-square tests. Cut-off for serum 25(OH) vitamin D (25(OH)D) was determined by ROC-analysis. Bonferroni correction was used for multiple comparisons.

Results

Hypocalcemia was identified in 54% cases (95% CI 49%–58%). Median and quartiles of age were 57 [47; 64] in group 1 and 59 [47; 64] in group 2. Median levels of serum parathyroid hormone (PTH), total calcium, albumin-corrected and ionized serum calcium, alkaline phosphatase (AP) and osteocalcin were significantly higher in group 1 (223.3 vs 165.7 pg/ml, 2.90 vs 2.81 mmol/l, 2.85 vs 2.72 mmol/l, 1.36 vs 1.32 mmol/l, 142 vs 111 IU/l, 64 vs 48.6 ng/ml, respectively, P < 0.001 for all), and phosphorus and serum 25(OH)D were lower in group 1 (0.81 vs 0.89 mmol/l, 15.9 vs 19.1 ng/ml, P = 0.002). Severe osteoporosis was more frequent in group 1 (14% vs 7%, P = 0.003). Taking cholecalciferol before PTE is associated with a lower incidence of postoperative hypocalcemia (27% vs 59%, P < 0.001, OR = 0.254, 95% CI 0.147–0.440). Cut-off for serum 25(OH)D as a predictor of postoperative hypocalcemia is 21.6 ng/ml with PPV = 61%, 95% CI 57%–64%, and NPV = 64%, 95% CI 56%–72%.

Conclusion

PTH, laboratory factors of calcium and bone metabolism, as well as severity of osteoporosis are associated with hypocalcemia in patients with PHPT after PTE. Taking cholecalciferol before PTE reduces the odds of postoperative hypocalcemia by 2–6 times.