Prospective Observation of 5-Year Clinical Course of Subclinical Hypothyroidism in Korean Population.
10.3346/jkms.2013.28.11.1622
- Author:
Woo Ri PARK
1
;
Tae Keun OH
;
Hyun Jeong JEON
Author Information
1. Department of Internal Medicine, Chungbuk National University School of Medicine, Cheongju, Korea. endoann@daum.net
- Publication Type:Original Article
- Keywords:
Subclinical Hypothyroidism;
Natural History;
Hypothyroidism
- MeSH:
Asymptomatic Diseases/*epidemiology;
Autoantibodies/blood/immunology;
Disease Progression;
Female;
Humans;
Hyperthyroidism/epidemiology;
Hypothyroidism/*epidemiology;
Male;
Middle Aged;
Prevalence;
Prospective Studies;
Republic of Korea/epidemiology;
Thyroglobulin/immunology;
Thyroid Function Tests;
Thyroid Gland/immunology;
Thyroid Nodule/epidemiology;
Thyroiditis/epidemiology;
Thyrotropin/*blood
- From:Journal of Korean Medical Science
2013;28(11):1622-1626
- CountryRepublic of Korea
- Language:English
-
Abstract:
Subclinical hypothyroidism (SCH) is a common clinical condition, whereas it's natural course has not been identified distinctly. We evaluated the natural history of 169 SCH patients over 5-yr and the prognostic factors including thyroid autoantibodies and thyroid ultrasonographic (USG) findings related to develop overt hypothyroidism. After 5 yr, 47.3% of patients showed normalization of TSH, while 36.7% of patients remained persistence of high level of TSH, and overt hypothyroidism developed in 11.2% of patients. There were painless thyroiditis (2.9%) and hyperthyroidism (1.7%) during 5 yr follow-up. The thyroid nodule was seen in 48.6% of patients. Most of patients had 1 to 2 nodules whereas only 3% of patients with thyroid nodule had more than 6 nodules. Overt hypothyroidism patients had more heterogenous echogenecity in USG compared to patients with normalization or persistent SCH (76.5% vs 50.0% vs 35.0%, P = 0.048) and higher prevalence positive anti-thyroid peroxidase (anti-TPO Ab) and anti-thyroglobulin antibody (anti-Tg Ab) and titer of anti-TPO Ab than other two groups. The cut off values for prediction of overt hypothyroidism were TSH > 7.45 microIU/mL, free T4 < 1.09 ng/dL and Anti-TPO Ab > 560 IU/mL. SCH has various courses and initial TSH, free T4, presence of thyroid autoantibody, titer of thyroid autoantibody; and thyroid USG findings can serve as a prognostic factor for progression of overt hypothyroidism. These parameters suggest consideration to initiate thyroid hormone treatment in SCH.
