Research Article
Levothyroxine Dose and Fracture Risk According to the Osteoporosis Status in Elderly Women
Young-Jin Ko, Ji Young Kim, Joongyub Lee, Hong-Ji Song, Ju-Young Kim, Nam-Kyong Choi, Byung-Joo Park
Published:
January 01, 2014
DOI:
10.3961/jpmph.2014.47.1.36
License:
Copyright © 2014 The Korean Society for Preventive Medicine2014This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
ObjectivesTo evaluate the association between fracture risk and levothyroxine use in elderly women with hypothyroidism, according to previous osteoporosis history.MethodsWe conducted a cohort study from the Korean Health Insurance Review and Assessment Service claims database from January 2005 to June 2006. The study population comprised women aged ≥65 years who had been diagnosed with hypothyroidism and prescribed levothyroxine monotherapy. We excluded patients who met any of the following criteria: previous fracture history, hyperthyroidism, thyroid cancer, or pituitary disorder; low levothyroxine adherence; or a follow-up period <90 days. We categorized the daily levothyroxine doses into 4 groups: ≤50 µg/d, 51 to 100 µg/d, 101 to 150 µg/d, and >150 µg/d. The hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with the Cox proportional hazard model, and subgroup analyses were performed according to the osteoporosis history and osteoporosis-specific drug prescription status.ResultsAmong 11 155 cohort participants, 35.6% had previous histories of osteoporosis. The adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.56 (95% CI, 1.03 to 2.37) in osteoporosis subgroup. In the highly probable osteoporosis subgroup, restricted to patients who were concurrently prescribed osteoporosis-specific drugs, the adjusted HR of fracture for the >150 µg/d group, compared with the 51 to 100 µg/d group, was 1.93 (95% CI, 1.14 to 3.26).ConclusionsWhile further studies are needed, physicians should be concerned about potential levothyroxine overtreatment in elderly osteoporosis patients.