Early biomarkers of hypocalcemia following total thyroidectomy

Abstract

Hypocalcemia is the most frequent major complication following total thyroidectomy (TT), delaying timely hospital demission. We prospectively evaluated the diagnostic utility of parathyroid hormone (PTH) measured one hour after TT and the delta (post-minus pre-surgery) PTH in order to determine which biomarker best predicted post-surgery hypocalcemia. Ninety-six consecutive patients, with either plurinodular goiter, Graves' disease or cervico-mediastinal goiter (22 (23%) men and 74 (77%) women, mean age 48.5 ± 15.2 and 47.9 ± 13.2 years, respectively), scheduled to undergo TT were enrolled. PTH was measured prior and one hour after surgery. Delta PTH was defined as one-hour post-surgery values minus pre-surgery PTH level. Hypocalcemia was defined as a calcemia under 8.0 mg/dL. Receiver operating characteristic (ROC) analysis was used to evaluate the Area Under Curve (AUC), sensibility and specificity of the two biomarkers for the occurrence of hypocalcemia. Forty-nine (51%) patients presented biochemical values under the cut-off but only 17 (18%) had clinical symptoms. Both variables yielded statistically significant AUC (PTH one-hour post surgery: 0.654; p = 0.0403; 95%CI: 0.519-0.773 and delta PTH: 0.659; p = 0.0263; 95%CI: 0.527-0.776). Although comparison of the two ROC curves did not yield significant differences, delta PTH yielded a better sensitivity and PTH one-hour post-TT yielded a marginally better specificity (sensitivity of 50% and 87% and specificity of 76% and 67% for cut-offs of <39.8 pg/dl and <54.5 pg/dl, respectively). Both biomarkers have similar diagnostic accuracy for hypocalcemia, and can be used to indicate when supplemental therapy should be implemented in order to favor a timely discharge.

Predictors of post-thyroidectomy hypocalcaemia: a systematic and narrative review

“…Low post-operative PTH was found to have a statistically significant association with transient biochemical hypocalcaemia in 24 studies, 10–33 compared with 3 studies where there was not a statistically significant result 34–36 . Low intra-operative PTH levels and a larger differential PTH from the pre-operative to post-operative stage were also seen to have statistically significant associations in 2 studies 37,38 and 13 studies 10,12,14,15,22,23,27,29,31,36,39–41 , respectively. Pre-operative PTH showed a non-significant association with transient biochemical hypocalcaemia in the majority of studies.…”

Impact of the new guidelines of the American Thyroid Association on the treatment of the differentiated thyroid tumor in an Italian center with medium-high volume thyroid surgery

“…Moreover, it led to a much-improved follow-up to a possible radiometabolic treatment. However, side effects included definitive hypoparathyroidism and lesions of the inferior laryngeal nerve [10].…”

Laboratory Indicators for Predicting Hypocalcemia After Total Thyroidectomy. A Study from A Tertiary Hospital in Saudi Arabia

“…Previous studies have reported that PTH provides a sensitivity of up to 96.4% for predicting hypocalcemia, with a specificity of 37.5-75%, although other studies have reported values that approached 100% [1,8] . We believe that these results are related to the larger patient populations from those studies, and it should be noted that mild hypocalcemia can occur even if there are normal postoperative PTH levels [10] . This is especially true in cases of vitamin D deficiency, as proposed by Pradeep et al [11] .…”