The use of prophylactic infusion of calcium gluconate compared to placebo in reducing the rate of early hypocalcaemia after total thyroidectomy: a double-blinded, randomized controlled trial.

Background: Hypocalcaemia as a common complication after total thyroidectomy [23-40% in University Malaya Medical Centre (UMMC)] and could result in prolonged hospital stay. We compared the early hypocalcaemia rate between prophylactic infusion of calcium and placebo among post total thyroidectomy patients and to establish whether prophylactic intravenous infusion of calcium reduces the rate of hypocalcaemia in the first 48 hours after surgery.

Methods: Patients undergoing elective total thyroidectomy in UMMC between June 2020-May 2022, were recruited and randomized to receive placebo or prophylactic calcium infusion. Both groups of patients received same dosages of post-operative prophylactic vitamin D and oral calcium. Early hypocalcaemia (within 48 hours) rate after surgery was the primary outcome and duration of hospital stay was the secondary outcome. The data collected was analysed using per-protocol analysis.

Results: Thirty-four patients were randomized equally (1:1) into both arms. No differences in the early hypocalcaemia rate between the intervention and placebo arms (0% vs. 5.8%, P>0.05). The median serum calcium levels were comparable between the intervention and placebo arms at 6 hours (2.33 vs. 2.37 mmol/L, P=0.59) and 48 hours (2.26 vs. 2.23 mmol/L, P=0.19) post-surgery. However, the median serum calcium level at 24 hours was statistically significantly higher in the intervention arm than the placebo arm (2.31 vs. 2.22 mmol/L, P=0.02). Similar duration of hospital stay between the both groups (2 vs. 2 days, P=0.81).

Conclusions: Routine prophylactic calcium infusion with oral calcium and vitamin D does not diminish the rate of early symptomatic hypocalcaemia post total thyroidectomy in a low-risk group. However, its usefulness needs to be further assessed in a large scale randomized controlled trial (RCT) incorporating more bigger population.

Trial registration: Registered on ClinicalTrials.gov (NCT04491357).