SingHealth Polyclinics, 167, Jalan Bukit Merah, Tower 5, #15-10, Singapore, 150167, Singapore.
Family Medicine Academic Clinical Program, Duke NUS Medical School, Singapore, Singapore.
BMC Prim Care. 2024 Oct 26;25(1):383. doi: 10.1186/s12875-024-02613-z.
Long-term management of patients with hypothyroidism on thyroxine replacement requires thyroid function test (TFT) monitoring once every six-12 months as recommended by clinical practice guidelines. This study determined their thyroid function status during two-year follow-up visits in primary care, and the factors influencing their thyroid status, and assessed the optimal interval for TFTs.
A retrospective cohort study was conducted on adults with a clinical diagnosis code for hypothyroidism in their electronic health records taken from a group of polyclinics in Singapore between July 2017 and June 2020. The follow-up thyroid status was categorized as under-replacement (TSH ≥ 3.70mIU/L), over-replacement (TSH ≤ 0.65mIU/L) or euthyroid (TSH 0.65-3.70mIU/L). The patients' demographic, clinical and TFT data were analyzed using appropriate statistical tests during the two-year follow-up. Stepwise logistic regression analysis identified the factors associated with suboptimal thyroid control. Kaplan-Meier analysis was used to compare their thyroid function status in association with the interval between TFT monitoring.
Data from 5,749 eligible subjects (mean age 62.1 ± 13.29 years; 79% female; 79.7% Chinese) were analyzed. After a two-year follow-up, 61.9% (n = 3558) of all subjects were euthyroid, with 29.5% (n = 1694) being under-replaced and 8.6% (n = 497) over-replaced. However, thyroid status did not differ significantly with the various dose regimen (daily, segmented, or alternate days) (p = 0.193). Stepwise logistic regression showed that thyroxine under-replacement was significantly associated with the male gender (AOR = 1.25,95%CI = 1.03-1.51,p = 0.02) and obesity (AOR = 1.34,95%CI = 1.08-1.66,p = 0.008). Every unit (μg/kg body weight) increase in the mean daily thyroxine dose was associated with 2.72 times greater odds of over-replacement. When comparing thyroid function monitoring at intervals of 13-24 months, monitoring at shorter intervals (≤ 12 months) was less likely to detect thyroxine under-replacement (AOR = 0.57,95%CI = 0.44-0.74,p < 0.001) and over-replacement (AOR = 0.62,95%CI = 0.41-0.97,p = 0.033). Among the 3,312 adults who were euthyroid at baseline, 22.2%, 41.7% and 59.6% had suboptimal thyroid control at 6, 12 and 24 months respectively (Kaplan-Meier analysis).
Around six in ten patients were euthyroid with thyroxine replacement for hypothyroidism in primary care over two years. Thyroxine under-replacement was associated with male gender and obesity. The proportion of euthyroid patients developing abnormal thyroid function doubled with TFTs at six, 12 and 24-month intervals.
根据临床实践指南的建议，甲状腺功能减退症患者在接受甲状腺素替代治疗时，需要每 6-12 个月进行一次甲状腺功能测试 (TFT) 监测。本研究旨在确定在初级保健中进行为期两年的随访时患者的甲状腺功能状态，以及影响甲状腺功能状态的因素，并评估进行 TFT 的最佳间隔时间。
对新加坡一组综合诊疗所的电子健康记录中患有临床诊断为甲状腺功能减退症的成年人进行回顾性队列研究，时间为 2017 年 7 月至 2020 年 6 月。随访时的甲状腺状态分为替代不足（TSH≥3.70mIU/L）、替代过度（TSH≤0.65mIU/L）或甲状腺功能正常（TSH 0.65-3.70mIU/L）。在两年的随访期间，使用适当的统计检验分析患者的人口统计学、临床和 TFT 数据。逐步逻辑回归分析确定与甲状腺控制不佳相关的因素。Kaplan-Meier 分析用于比较他们的甲状腺功能状态与 TFT 监测间隔的关系。
分析了 5749 名合格受试者的数据（平均年龄 62.1±13.29 岁；79%为女性；79.7%为华人）。经过两年的随访，所有患者中有 61.9%（n=3558）甲状腺功能正常，29.5%（n=1694）替代不足，8.6%（n=497）替代过度。然而，不同的甲状腺素剂量方案（每日、分段或隔日）并没有显著影响甲状腺状态（p=0.193）。逐步逻辑回归显示，甲状腺素替代不足与男性（优势比[OR] 1.25，95%置信区间 [CI] 1.03-1.51，p=0.02）和肥胖（OR 1.34，95%CI 1.08-1.66，p=0.008）显著相关。每日平均甲状腺素剂量每增加 1μg/kg 体重，替代过度的可能性增加 2.72 倍。与间隔 13-24 个月的甲状腺功能监测相比，间隔更短（≤12 个月）的监测不太可能检测到甲状腺素替代不足（OR 0.57，95%CI 0.44-0.74，p<0.001）和替代过度（OR 0.62，95%CI 0.41-0.97，p=0.033）。在基线时甲状腺功能正常的 3312 名成年人中，分别有 22.2%、41.7%和 59.6%在 6、12 和 24 个月时出现甲状腺功能控制不佳（Kaplan-Meier 分析）。
在两年的时间里，大约十分之六的甲状腺功能减退症患者在初级保健中接受甲状腺素替代治疗后甲状腺功能正常。甲状腺素替代不足与男性和肥胖有关。每六个月、每 12 个月和每 24 个月进行一次 TFT，甲状腺功能正常患者出现异常甲状腺功能的比例分别增加了两倍、四倍和五倍。
