Endocrine Abstracts

Introduction: Postoperative hypocalcemia is among the most frequent morbidities after total thyroidectomy. Although most postoperative hypocalcemia is temporary, it causes prolonged hospitalization and a decrease in quality of life. For all this, early diagnosis is essential to start treatment as soon as possible. In this study, we determined whether early serum calcium levels can predict the development hipoparathyroidism.

Methods: A total of 122 patients underwent total thyroidectomy with or without neck dissection between 2016 and 2017 were reviewed. Total calcium levels were evaluated at 6 h, 1 day an 1 month postoperatively. Serial serum calcium measurements were recorded as well as details of the operation, pathology, demographic and clinical data. To assess the value of the most appropriate test for the diagnosis of hypoparathyroidism, the sensitivity and specificity of calcium at 6 and at 24 h was studied and the area under the receiver operating characteristic (ROC) curve (AUC) was used to measure the relative predictability of these variables or criteria.

Results: 63.9% patients did not develop hypocalcaemia but 29.5% were found to have temporary hypocalcaemia and 6.6% had permanent hypocalcaemia. No differences were observed for sex, age, neck dissection types and pathology between normocalcemic and hypocalcemic patients. The average calcium was 8.4 mg/dl at 6 h and 8.05 at 1 day postoperatively (P<0.05). For the diagnosis of transient hypocalcemia, AUC from 6 and 24 h calcium levels was 0.724 and 0.963 respectively (P<0.001). The threshold of 7.75 mg/dl was obtained by means of the ROC curve analysis, with 98% of sensitivity and 66% specifity from 6 h calcium, and 8 mg/dl with 89% of sensitivity and 68% specifity from 1 day postquirurgical calcium. However for the diagnosis of permanent hypocalcemia, AUC from 6 and 24 h calcium levels was 0.797 and 0.691 respectively (P<0.001) and the calculated threshold of 7.45 mg/dl (94% sensitivity and 75% especifity) from 6 h calcium and 6.95 mg/dl (93% sensitivity and 87% specificity) from 1 day postquirurgical calcium.

Conclusion: Post-thyroidectomy hypocalcemia is a common complication of total thyroidectomy. Our results suggest that the calcium levels on day 1 postoperatively are useful in predicting the development of hypocalcemia and the hypoparathyroidism diagnosis.