title: Natural history of mild subclinical hypothyroidism in a middle-aged and elderly Chinese population: a prospective study.
abstract: Subclinical hypothyroidism (SCH) has a high global prevalence. Most SCH patients have mild cases (thyrotropin ≤10 mIU/L). Treatment recommendations for mild SCH are controversial, which raises concerns about the natural history of mild SCH. We aimed to clarify the natural history of mild SCH. This is a prospective population-based study. We measured thyroid function in 11,000 participants in the REACTION study and followed 505 newly diagnosed mild SCH patients aged 40-years or older between 2011 and 2014. Logistic regression analysis was used to seek baseline parameters associated with the natural outcomes of mild SCH. Among 505 mild SCH patients, 221 (43.8%) had persistent SCH, 251 (49.7%) reverted to euthyroidism, and 17 (3.4%) progressed to overt hypothyroidism (OH). Patients with higher baseline total cholesterol (TC, between 201.0-240.0 mg/dL or >240.0 mg/dL vs. <201.0 mg/dL, p = 0.048 and 0.006, respectively) or positive thyroid peroxidase antibodies (TPOAb, p = 0.009) had higher risks of progression to OH, while those with higher baseline creatinine (CR, between 0.71-0.80 mg/dL or >0.80 mg/dL vs. ≤0.65 mg/dL, p = 0.031 and 0.004, respectively), higher baseline thyrotropin (≥7 mIU/L, p < 0.001) or older (>60 years vs. ≤50 years, p = 0.012) had lower odds of reverting to euthyroidism. In conclusion, TPOAb and TC seem to be more important predictors of progression to OH than initial thyrotropin, whereas high baseline thyrotropin or CR were negative correlated with reversion to euthyroidism. The prognostic value of TC and CR in mild SCH should be considered.
authors.affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Endocrinology and Metabolism, The First Hospital of Lanzhou University, Lanzhou 730000, China.
authors.forename: Donghu
authors.initials: D
authors.lastname: Zhen
authors.affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Guan
authors.affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Science and Education, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China.
authors.forename: Shujian
authors.initials: S
authors.lastname: Ge
authors.affiliation: Department of Endocrinology and Metabolism, The First Hospital of Lanzhou University, Lanzhou 730000, China.
authors.forename: Xulei
authors.initials: X
authors.lastname: Tang
authors.affiliation: Scientific Center, Shandong Provincial Hospital affiliated to Shandong University, Shandong 250021, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Gao
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000208:ethnology / Q000502:physiology*; D044466:Asian People / Q000706:statistics & numerical data; D058070:Asymptomatic Diseases; D002681:China / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012720:Severity of Illness Index
keywords: Hypothyroidism; Natural history; Prospective study; Risk factors; Thyrotropin