Post-operative parathyroid hormone can be used as a predictor of normocalcaemia after total thyroidectomy.

INTRODUCTION Development of hypocalcaemia is a serious complication to total thyroidectomy (TT). The measurement of intact plasma parathyroid hormone (iPTH) has been internationally described as a good predictor of hypocalcaemia. Despite this, consensus in the field has yet to be reached among clinicians. We aimed to evaluate if measurement of iPTH 24 hours post-operatively (24-iPTH) can identify patients who do not subsequently develop clinically significant hypocalcaemia (CSH), thereby allowing for early discharge after TT. METHODS This was a historic cohort study of all patients who had a TT in the period from January 2013 to March 2014 at the Department of Oto-rhino-laryngology, Aarhus University Hospital, Denmark. Only patients with 24-iPTH measurements were included. Post-operative treatment with calcium or activated vitamin D analogue was defined as CSH. Data were collected from medical records. RESULTS A total of 69 patients were included, 80% were women, the median age was 47 and 83% had a malignant disease. A total of 35% developed CSH and the median hospitalisation period was four days. The sensitivity, specificity and positive predictive value of 24-iPTH ≥ 2.8 pmol/l to exclude CSH were 76%, 92% and 94%, respectively. In addition, we found that a body mass index > 25 kg/m(2) significantly increased the risk of developing CSH. CONCLUSIONS The measurement of 24-iPTH ≥ 2.8 pmol/l can be used to predict patients who will not develop CSH after TT and allow for early discharge of more than 50% of the patients. FUNDING none. TRIAL REGISTRATION not relevant.