The effect of suppressive thyroxine therapy in nodular goiter in postmenopausal women and 2 year’s bone mineral density change

The efficacy of thyroxine suppressive therapy in reducing nodular growth and its effect to bone mineral density (BMD) in postmenopausal women is still debated. This study aimed to evaluate the therapeutic effect of thyroxine and its influence on BMD. Postmenopausal women with nodular or multinodular goiter during 2013-2015 at Chang Gung Memorial Hospital were enrolled and retrospectively traced back to the first date of visit or treatment. Ninety-four eligible patients were enrolled, of whom 45 were thyroxine-treated (LT-4 group) and 49 were treatment-naïve (control group). Data, including volume of nodules, were analyzed retrospectively. BMD was measured in each LT-4 group patient since the year of enrollment. Nodular volumes were reduced in both LT-4 (from 4.89 ± 4.46 to 4.10 ± 4.57 mL, p = 0.033) and control group (3.48 ± 4.36 to 3.09 ± 2.88 mL, p = 0.239) at initial 2-year follow-up. Nodular volume in LT-4 group increased insignificantly (from 4.89 ± 4.46 to 4.91 ± 5.40 mL, p = 0.711) at the end of 7-year follow-up. The best cut-off predictive nodular volume that may have responded to thyroxine is 2.6 mL (AUC, 0.740; sensitivity, 0.750; specificity, 0.733) during first 2 year. Lumbar spine, total hip and femoral neck BMD were not significantly changed during 2 year's thyroxine suppression therapy. In conclusion, thyroxine suppressive therapy in postmenopausal women had significant reduction in nodule volume at initial 2 years of treatment, especially in volume larger than 2.6 mL. Prolonged thyroxine treatment did not benefit nodular size reduction and may affect BMD minimally in postmenopausal women.