Serum PTH and Ionized Calcium Levels as Predictors of Symptomatic Hypocalcemia after Parathyroidectomy

Abstract

To evaluate whether perioperative PTH levels or ionized calcium levels are associated with symptomatic hypocalcaemia, in patients undergoing parathyroidectomy for primary hyperparathyroidism. Prospective noncontrolled study of a cohort of 100 patients, undergoing parathyroidectomy at a single tertiary care medical centre. Prospectively collected data from January 2002 to April 2008 on 100 unique patients undergoing parathyroidectomy for primary hyperparathyroidism were evaluated for age, sex, preoperative and intraoperative PTH levels, and preoperative and postoperative ionized calcium levels, extent of operation, final pathology, and postoperative symptomatic hypocalcaemia. Comparisons of those with and without symptomatic hypocalcaemia were made with Fisher's exact test for binary characteristics and with the Wilcoxon test for continuous characteristics. Results were deemed statistically significant at the 5% level (p < 0.05) with no correction for multiple comparisons. Twelve patients (12%) developed symptomatic hypocalcaemia in the post operative period. Neither, initial levels nor subsequent changes in PTH or ionized calcium were found to be associated with symptomatic postoperative hypocalcaemia. Patients developing hypocalcaemia tended to be younger (p = 0.057) and showed a significantly higher percentage when multiple glands were removed (p = 0.026). Initial levels or subsequent changes in PTH or ionized calcium were not found to be associated with symptomatic hypocalcaemia. The removal of more than one gland did correlate with symptomatic post operative hypocalcaemia.