Thyroid Department, Endocrinology Service, Minas Gerais, Brazil.
Clin Endocrinol (Oxf). 2010 May;72(5):685-8. doi: 10.1111/j.1365-2265.2009.03696.x.
One important aspect in the decision to treat or not elderly patients with subclinical hyperthyroidism (SCH) is the risk of progression to overt hyperthyroidism (OH).
To define the natural history of endogenous SCH in elderly patients with TSH between 0.1 and 0.4 mIU/l.
Prospective study. One hundred and two women aged >or=60 years with persistently low TSH ranging from 0.1 to 0.4 mIU/l and normal free T4 and T3 were studied. Patients using L-T4 or antithyroid drugs, previously treated for hyperthyroidism, with pituitary disease, using corticosteroids, amiodarone, dopaminergic agonists, with atrial fibrillation or heart disease were excluded. Seven patients had Graves' disease, 91 had nodular disease and 4 presented no defined cause. The time of follow-up ranged from 12 to 70 months (median 41 months).
Three patients progressed to OH (elevated T4 and/or T3) and four other patients to persistently low TSH (<0.1 mIU/l) in the presence of increase in serum T3 when compared with baseline. These patients were treated. Twenty-four women presented sustained normalization of TSH and none progressed to hypothyroidism. SCH with TSH in the 0.1-0.4 mIU/l range persisted in 71 patients, 4 of them (5.6%) being treated because of the development of atrial fibrillation or heart disease during follow-up. The only independent predictor of progression of SCH was an initial TSH value <0.2 mIU/l.
In elderly patients with endogenous SCH and TSH between 0.1 and 0.4 mIU/l progression to clinical hyperthyroidism is uncommon (approximately 1% per year), spontaneous TSH normalization may occur, and persistence of SCH for many years is the most likely.
在决定是否治疗有亚临床甲状腺功能亢进（SCH）的老年患者时，一个重要因素是发展为显性甲状腺功能亢进（OH）的风险。
定义 TSH 在 0.1 至 0.4 mIU/L 之间的老年内源性 SCH 患者的自然病史。
前瞻性研究。研究了 102 名年龄>60 岁且持续 TSH 处于 0.1 至 0.4 mIU/L 之间且游离 T4 和 T3 正常的女性患者。排除正在使用 L-T4 或抗甲状腺药物、先前因甲状腺功能亢进而接受治疗、有垂体疾病、使用皮质类固醇、胺碘酮、多巴胺激动剂、有房颤或心脏病的患者。有 7 名患者患有格雷夫斯病，91 名患者患有结节性疾病，4 名患者无明确病因。随访时间为 12 至 70 个月（中位数为 41 个月）。
3 名患者进展为 OH（T4 和/或 T3 升高），4 名患者在基线时 T3 增加的情况下出现持续低 TSH（<0.1 mIU/L）。这些患者接受了治疗。24 名女性患者 TSH 持续正常，无一例进展为甲状腺功能减退症。71 名患者存在 SCH，TSH 处于 0.1-0.4 mIU/L 范围内，其中 4 名（5.6%）因随访期间出现房颤或心脏病而接受治疗。SCH 进展的唯一独立预测因素是初始 TSH 值<0.2 mIU/L。
在 TSH 在 0.1 至 0.4 mIU/L 之间的老年内源性 SCH 患者中，进展为临床甲状腺功能亢进症的情况并不常见（每年约 1%），可能会自发恢复 TSH 正常，并且多年持续存在 SCH 的可能性最大。
