Duce Helen L, Duff Christopher J, Zaidi Syed, Parfitt Ceri, Heald Adrian H, Fryer Anthony A
Department of Clinical Biochemistry, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, UK.
School of Medicine, Keele University, Keele, UK.
Bipolar Disord. 2023 Aug;25(5):402-409. doi: 10.1111/bdi.13298. Epub 2023 Jan 23.
Blood test monitoring is essential for the management of lithium treatment and National Institute for Health and Care Excellence guidance recommends 6-monthly serum testing of thyroid function. We examined conformity to these guidelines and the impact of monitoring outside these intervals.
We extracted serum lithium and thyroid hormone results at one centre between January 2009 and December 2020. We identified 266 patients who started lithium during this period with no history of thyroid abnormality within the previous 2 years and were at risk of developing thyroid abnormalities. We examined the interval between tests, time between onset of lithium testing and first thyroid-stimulating hormone (TSH) outside the laboratory reference range and assessed impact of testing outside recommended 6-monthly intervals.
The most common testing frequency was 3 months (±1 month), accounting for 17.3% of test intervals. Kaplan-Meier analysis showed that most thyroid dysfunction manifests within 3 years (proportion with abnormal TSH at 3 years = 91.4%, 19.9% of total patients). In the first 3 months after commencing lithium therapy, eight patients developed subclinical hypothyroidism and had clinical follow-up data available. Of these, half spontaneously normalized without clinical intervention. In the remaining patients, thyroxine replacement was only initiated after multiple occasions of subclinical hypothyroidism (median = 2 years after initiating lithium, range: 6 months to 3 years).
The peak interval at 3 months suggests that thyroid function is frequently checked at the same time as serum lithium, indicating too frequent testing. Our data support the recommended 6-monthly testing interval and highlight poor adherence to it.
血液检测监测对于锂盐治疗的管理至关重要，英国国家卫生与临床优化研究所的指南建议每6个月进行一次甲状腺功能血清检测。我们研究了对这些指南的遵循情况以及超出这些检测间隔进行监测的影响。
我们提取了2009年1月至2020年12月期间某一中心的血清锂和甲状腺激素检测结果。我们确定了在此期间开始使用锂盐治疗、过去2年内无甲状腺异常病史且有发生甲状腺异常风险的266例患者。我们检查了检测间隔、开始锂盐检测至首次促甲状腺激素（TSH）超出实验室参考范围的时间，并评估了超出推荐的每6个月检测间隔进行检测的影响。
最常见的检测频率是3个月（±1个月），占检测间隔的17.3%。Kaplan-Meier分析显示，大多数甲状腺功能障碍在3年内出现（3年时TSH异常的比例 = 91.4%，占总患者的19.9%）。在开始锂盐治疗后的前3个月，8例患者出现亚临床甲状腺功能减退且有临床随访数据。其中，一半患者未经临床干预自行恢复正常。在其余患者中，仅在多次出现亚临床甲状腺功能减退后才开始使用甲状腺素替代治疗（中位数 = 开始使用锂盐后2年，范围：6个月至3年）。
3个月的峰值检测间隔表明，甲状腺功能检测常与血清锂检测同时进行，这意味着检测过于频繁。我们的数据支持推荐的每6个月检测间隔，并凸显了对该间隔的依从性较差。
