Risk factors for postoperative hypocalcemia

Hypocalcaemia is one of the most common complications after thyroidectomy; however, it is still unclear what preoperative factors could predict this event. The aim of this study was to evaluate the role of risk factors for hypocalcaemia after total thyroidectomy (TT). Consecutive patients who underwent total thyroidectomyat our institution between January 2014 and January 2016 were enrolled. The clinical and pathologic characteristics and surgical details of normocalcemic and hypocalcemic patients were compared. Univariate and multivariate analyses to estimate risk ratio were assessed. A total of 328 patients underwent TT; histology revealed benign and malignant disease in 83 and 17% of cases, respectively. Central-compartment neck dissection (CCND) was performed in 36 subjects (10.9%). Parathyroid glands were observed in 23% (76) of specimens. Laboratory asymptomatic hypocalcaemia was observed in 92 (28%) patients; symptomatic hypocalcaemia occurred in 26 (7.9%). Transient hypocalcaemia has been observed in 48 (14.6%) patients; permanent hypocalcaemia occurred in two subjects (0.6%). On univariate analysis, malignant pathology (p < 0.001), CCND (p < 0.05), female gender (p < 0.001), presence of at least two parathyroid glands in specimens (p < 0.002), and operative time longer than 120 min (p < 0.05) were factors that significantly increased the risk of developing asymptomatic and transient hypocalcaemia. After logistic regression analysis, malignant pathology (p < 0.000; p < 0.001) and CCND (p < 0.005; p = 0.013) were the significant factors that affected the development of symptomatic and transient hypocalcaemia. The presence of malignant pathology and CCND was found to be significant risks factors for postoperative hypocalcaemia. In patients in whom this pathological features are present, attention should be paid to rapidly start an adequate therapy.