Risk Factors of Post-Hemithyroidectomy Hypothyroidism

Abstract

Introduction: Hemithyroidectomy is one of the most frequently performed procedures often associated with complications, among which hypothyroidism is the most common. However, the risk factors for post hemithyroidectomy hypothyroidism are still unclear.

Objectives: To assess the incidence, risk factors and time taken to develop hypothyroidism after hemithyroidectomy.

Methods: A retrospective chart review of patients who underwent hemithyroidectomy between 2004 and 2012 in two different hospitals was performed. Patients were analyzed for age, gender, weight, height, body mass index (BMI), previous medical history and histological findings. The incidence of post hemithyroidectomy hypothyroidism was determined based on the thyroid stimulating hormone levels during the postoperative period.

Results: From a total of 213 patients, 83 met our inclusion criteria; 67 (80.7%) were women and 16 (19.3%) were men. Thirty-seven (45%) patients developed biochemical hypothyroidism postoperatively whereas 46 patients remained euthyroid (55%). The time taken to develop hypothyroidism was variable. Twenty-four (61.5%) of 37 patients developed hypothyroidism within the first 3 months postoperatively. There were no significant differences in gender, age, BMI, history of diabetes mellitus, the presence of thyroiditis in histopathological examination and postoperative pathologies between the postoperative hypothyroid and euthyroid groups.

Conclusions: Our results showed a high overall incidence of hypothyroidism following hemithyroidectomy (45%). As the majority of the patients in the hypothyroid group (70.3%) developed hypothyroidism within the first 6 months of post surgery, frequent thyroid function testing in the first 6 months, may help in initiating the treatment before the patient becomes symptomatic. We demonstrated that there are no predictive risk factors for post hemithyroidectomy hypothyroidism.

Keywords: Hemithyroidectomy; hypothyroidism; thyroiditis.