Johnson Louise, Rayner Brian
Montana Hospital, Pretoria, South Africa.
Division of Nephrology and Hypertension, and Kidney and Hypertension Research Unit, University of Cape Town, South Africa. Email:
Cardiovasc J Afr. 2020;31(1):5-8. doi: 10.5830/CVJA-2019-036. Epub 2019 Aug 2.
Previous reports have suggested an association between hypothyroidism and macrovascular complications in type 2 diabetes (T2DM) but the association with microvascular complications is not well documented. This study aimed to determine whether there were significant differences in these complications in patients with T2DM with and without hypothyroidism.
This was a retrospective, cross-sectional, case-control study from a single centre specialising in diabetes in South Africa. T2DM was defined by American Diabetes Association criteria. The cases were all patients treated for hypothyroidism and the controls were clinically and biochemically confirmed euthyroid, who were under follow up between 1 January and 1 July 2016. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) of < 60 ml/min, determined by the CKD-epidemiology collaboration equation (CKD-EPI) and/or albumin/creatinine ratio > 3 mg/mmol. Diabetic retinopathy (DR) was defined as the presence of aneurysms, bleeds, exudates and new vessel formation on the retina examined by an ophthalmologist. Diabetic peripheral neuropathy (DPN) was defined as the presence of symptoms, loss of 128-Hz sensation and abnormal 10-gm monofilament. Cardiovascular disease (CVD) was defined as the presence of major adverse cardiovascular events (MACE).
There were 148 cases and 162 controls. Compared to the controls, the cases were older (65.6 vs 59.4 years, p < 0.00001), more likely to be female (67.6 vs 39.5%, p < 0.0001) and white (89.2 vs 79.6%, p = 0.02), have a lower HbA level (7.5 vs 8.2%, p = 0.0001), eGFR (64.4 vs 72.7 ml/min, p = 0.0006) and triglyceride level (2.18 vs 2.55 mmol/l, p = 0.04), have a higher high-density lipoprotein cholesterol level (1.13 vs 1.02 mmol/l, p = 0.001), a longer duration of diabetes (14.8 vs 11.6 years, p = 0.001) and using fewer antidiabetic agents (1.82 vs 2.19, p = 0.001). There was a higher prevalence of CKD (44 vs 57.8%, p = 0.03) and CVD (59.3 vs 45.3, p = 0.06), and a trend towards higher DR (66.7 vs 47.6, p = 0.09). There was no difference in body mass index, hypertension, low-density lipoprotein cholesterol level (all patients received statin therapy), DPN and amputations. After adjusting for confounding factors, there was no association between CKD and DR, and hypothyroidism, but the trend to association with CVD persisted (OR 1.97. p = 0.07).
Hypothyroidism in T2DM was not associated with microvascular disease after adjusting for confounding factors. There was a nearly two-fold risk of CVD. The study is limited by the retrospective and observational design.
既往报告提示甲状腺功能减退与2型糖尿病（T2DM）的大血管并发症之间存在关联，但与微血管并发症的关联尚无充分文献记载。本研究旨在确定合并和未合并甲状腺功能减退的T2DM患者在这些并发症方面是否存在显著差异。
这是一项来自南非一家糖尿病专科中心的回顾性横断面病例对照研究。T2DM根据美国糖尿病协会标准定义。病例为所有接受甲状腺功能减退治疗的患者，对照为临床和生化检查确诊甲状腺功能正常的患者，他们在2016年1月1日至7月1日期间接受随访。慢性肾脏病（CKD）定义为根据慢性肾脏病流行病学合作公式（CKD-EPI）确定的估计肾小球滤过率（eGFR）<60 ml/min和/或白蛋白/肌酐比值>3 mg/mmol。糖尿病视网膜病变（DR）定义为眼科医生检查视网膜时存在动脉瘤、出血、渗出物和新生血管形成。糖尿病周围神经病变（DPN）定义为存在症状、128 Hz感觉丧失和10 g单丝异常。心血管疾病（CVD）定义为存在主要不良心血管事件（MACE）。
共有148例病例和162例对照。与对照相比，病例年龄更大（65.6岁对59.4岁，p<0.00001），女性比例更高（67.6%对39.5%，p<0.000１），白人比例更高（89.2%对79.6%，p=0.02），HbA水平更低（7.5%对8.2%，p=0.000１），eGFR更低（64.4 ml/min对72.7 ml/min，p=0.0006），甘油三酯水平更低（2.18 mmol/l对2.55 mmol/l，p=0.04），高密度脂蛋白胆固醇水平更高（1.13 mmol/l对1.02 mmol/l，p=0.0０1），糖尿病病程更长（14.8年对11.6年，p=0.001），使用的抗糖尿病药物更少（1.82种对2.19种，p=0.001）。CKD（44%对57.8%，p=0.03）和CVD（59.3%对45.3%，p=0.06）的患病率更高，DR也有升高趋势（66.7%对47.6%，p=0.09）。体重指数、高血压、低密度脂蛋白胆固醇水平（所有患者均接受他汀类药物治疗）、DPN和截肢方面无差异。校正混杂因素后，CKD、DR与甲状腺功能减退之间无关联，但与CVD的关联趋势仍然存在（比值比1.97，p=0.07）。
校正混杂因素后，T2DM中的甲状腺功能减退与微血管疾病无关。CVD风险增加近两倍。本研究受回顾性和观察性设计的限制。
