INCIDENCE AND PREDICTORS OF POST-THRYOIDECTOMY HYPOCALCEMIA

Abstract

INTRODUCTION
Post-thyroidectomy hypocalcemia is common but variably reported. We studied the incidence and predictors of postthyroidectomy hypocalcemia in our population.

METHODOLOGY
Two hundred seventy-seven patients, who underwent thyroidectomy for either a benign or a malignant thyroid condition at the University Medical Center, Ho Chi Minh city, Viet Nam, were prospectively studied from November 2017 to April 2018. Blood samples for serum calcium and albumin were collected before, and on the first postoperative day (POD1). Patients with preoperative hypocalcemia were excluded. Clinical examination, extent of thyroidectomy, and histopathological diagnosis were recorded. Postoperative hypocalcemia was defined as corrected plasma calcium value <2.1 mmol/L.

RESULTS
The median age of the 277 patients was 41 years (range: 17-74 years). 186/277 (81.9%) were female. Hypocalcemia on POD1 was recorded in 117 patients (51.5%), among whom 85 (72.6%) were symptomatic. Hypocalcemic symptoms developed on POD1 itself in 66 out of the 85 patients (77.6%) who were symptomatic. Interestingly, 32 out of the 117 patients (27.4%) who had hypocalcemia were asymptomatic. In multivariate analysis, age < 50 years (OR 2.2, 95% CI 1.1 – 4.1, p=0.012), preoperative plasma calcium value (OR 0.023, 95% CI 0.001 – 0.456, p=0.013) and total thyroidectomy (OR 2.1, 95% CI 1.0–4.5, p=0.047) were statistically significant predictors of post-thyroidectomy hypocalcemia.

CONCLUSION
Hypocalcemia is common after thyroidectomy (51.5% of patients on POD1). Age less than 50 years, low preoperative plasma calcium value, and total thyroidectomy were the significant predictors of post-thyroidectomy hypocalcemia.