Analysis of options for prescribing hormone replacement therapy after thyroid organ-sparing surgery

Abstract

Background. Performing thyroid organ-sparing surgery primarily aims to preserve the quality of life. Organ-sparing surgery should be understood as hemithyroidectomy with mandatory removal of the isthmus and pyramidal lobe of the thyroid (if present). The choice of one or another concept of prescribing hormone replacement therapy remains debatable. The purpose of the study is to determine the proportion of patients who do not need replacement therapy with levothyroxine after organ-sparing surgery on the thyroid gland, among those who were prescribed replacement therapy immediately and one month after discharge from the hospital, as well as to analyze the factors causing hypothyroidism in people with hemithyroidectomy. Materials and methods. The first group included 82 patients with hemithyroidectomy who were prescribed replacement therapy immediately after discharge from the hospital. The second group included 61 patients with hemithyroidectomy. The administration of replacement therapy was postponed for one month. A month after the operation, clinical examinations and monitoring of thyroid-stimulating hormone and free thyroxine indicators were performed. Results. After one month of observation, 72 (87.8 %) of 82 patients in the first group continued to take levothyroxine, and 8 (13.1 %) of 61 persons in the second group began to take it. In the first group, there was a moderate direct correlation between thyroid-stimulating hormone level before surgery and levothyroxine dose one month after (Spearman’s correlation coefficient 0.304, p = 0.009). It was found that the chances of continuing taking levothyroxine after one month in the first group were 47 times hig­her than the chances of prescribing levothyroxine after one month in the second group. The proportion of patients in the first group who continued to take levothyroxine after one month was significantly higher than the proportion of patients in the second group who started taking levothyroxine after one month (87.8 ± 3.6 % vs. 13.1 ± 3.5 %, p < 0.0001, Fisher’s exact test). Conclusions. Among patients who were prescribed hormone replacement therapy immediately after hemithyroidectomy, 12.2 % did not need to continue taking levothyroxine after one month. Among persons in whom the administration of hormone replacement therapy was postponed for one month after hemithyroidectomy, 86.9 % of patients did not require the use of levothyroxine in the future. The volume of the thyroid remnant ≤ 3.67 cm3 can be considered a predictor for hypothyroidism occurrence in the future, with a high risk of prescribing hormone replacement therapy. The study of such a factor as the ratio of the remnant thyroid volume to the body weight did not provide statistically reliable data for its use as a predictor of hypothyroidism occurrence in the postoperative period.