Correlation Among Thyroid Hormone and Microvascular Complications in Euthyroid Patients with T2DM

Research Article

J Pediatri Endocrinol. 2024; 9(1): 1063.

Correlation Among Thyroid Hormone and Microvascular Complications in Euthyroid Patients with T2DM

Lei-Lei Cheng; Bo-Wei Liu; Fu-Zai Yin*

Department of Endocrinology, First Hospital of Qinhuangdao, Province People’s Republic of China

*Corresponding author: Fu-zai YiDepartment of Endocrinology, First Hospital of Qinhuangdao No. 258, Wenhua Road, Qinhuangdao, 066000 Hebei Province People’s Republic of China. Email: yinfuzai62@163.com

Received: January 17, 2024 Accepted: February 22, 2024 Published: February 29, 2024

Abstract

Objective: To investigate the relation among thyroid hormone and Diabetic Microvascular Complications (DMVC) in euthyroid patients with Type 2 Diabetes Mellitus (T2DM).

Methods: We retrospectively analysis was performed for 785 euthyroid patients with T2DM from June 2019 to August 2020 which were hospitalized in the Department of Endocrinology of the First Hospital of Qinhuangdao, and 289 patients had at least one DMVC. The prevalence of Diabetic Retinopathy (DR) was 15.16%, Diabetic Nephropathy (DN) was 31.08% and Diabetic Peripheral Neuropathy (DPN) was 29.30%. The effect of thyroid hormone on DMVC were compared.

Results: Logistic regression analysis showed that, low FT3 was an independent risk factor for DR and DN (OR=0.542, 95% CI: 0.357-0.825, P=0.004; OR=0.715, 95% CI: 0.523-0.977, P=0.035). No significant relation showed between FT4 TSH and DR DN.

Conclusion: Euthyroid patients with T2DM with retinopathy and/or nephropathy had lower FT3 concentrations, while no association between FT4 and TSH and diabetic microvascular complications was found. There may be a certain association between poor glycemic control, low FT3 concentration, and microvascular complications in patients with T2DM, and future studies need to confirm the causal relationship and exact mechanism.

Keywords: Thyroid hormone; Type 2 diabetes mellitus; Diabetes microvascular complications

Abbreviations: TH: Thyroid Hormone; DMVC: Diabetic Microvascular Complications; T2DM: Type 2 Diabetes Mellitus; DR: Diabetic Retinopathy; DN: Diabetic Nephropathy; DPN: Diabetic Peripheral Neuropathy; TSH: Thyroid-Stimulating Hormone; FT3: Free Serum Triiodothyronine; BMI: Body Mass Index

Introduction

Worldwide, about 540 million persons have diabetes [1]. Various complications occur during disease progression, such as Diabetic Retinopathy (DR), Diabetic Nephropathy (DN), Diabetic Peripheral Neuropathy (DPN), and macrovascular complications. As the disease progresses, various forms occur that lead to blindness, kidney failure, and even life-threatening conditions. Many studies on the pathogenesis of DMVC were conducted, but the exact mechanism and effective treatment need to be further explored.

Thyroid hormone receptors are present in vascular endothelial tissues throughout the body, so thyroid hormone concentration affects vascular lesions. Numerous clinical studies have confirmed effect abnormal thyroid function is associated with DMVC. However, the exact mechanism on the relationship between patients with normal thyroid function and DMVC studies and new strategies for treatment require further study.

Methods

Study Participants

785 T2DM patients with normal thyroid function were collected who were hospitalized in the Department of Endocrinology of the First Hospital of Qinhuangdao from June 2019 to August 2020, (436 men, 349 women, median age 57.02±13.82). Patients were excluded if they had type 1 or other types of diabetes, acute complications of uncorrected diabetes mellitus, a history of hypothalamic or pituitary disorder, thyroid malignant disease, dythyroidism, oral thyroid-related drug therapy, hepatic insufficiency (2.5 times the normal value of AST and ALT), malignancy, pregnancy or lactation, anemia and hypoproteinic dystrophy, acute infectious states, and ocular history affecting fundus photography, such as trauma, eye injections, and surgery. The Ethics Committee of Qinhuangdao First Hospital approved this study, and all enrolled patients signed informed consent.

Research Methods

Type 2 diabetes mellitus diagnostic criteria: Accord with the criteria of the American Diabetes Association [2]. Diabetic Retinopathy (DR) diagnostic criteria: All subjects underwent ophthalmograms and fundus photography [3]. Experienced ophthalmologists used the Obaur ultra-wide-angle laser scanning camera [4] to acquire digital retinal photographs, and diagnoses met the international diabetic retinopathy criteria [3]. Diabetic Nephropathy (DN) diagnostic criteria: After exclusion of renal organopathy and urinary tract infection, results were consistent with eGFR =60 ml/min/1.73 m² and/or ACR=30 mg/g [5]. Diabetic Peripheral Neuropathy (DPN) diagnostic criteria: Patients had at least two positive results in sensory symptoms, signs, or abnormal reflexes. Abnormal nerve conduction tests were defined as the presence of at least one abnormality (amplitude, incubation period, F-wave, or nerve conduction velocity) in two or more nerves between the median, peroneal, and sural nerves [6]. Diagnostic criteria for normal thyroid function: FT3(1.58-3.91pg/ml), FT4(0.70-1.48ng/dl) and TSH (0.35-4.94uIU/ml).

Participants were divided into DR (n=119), DN (n=244), and DPN (n=230) groups according to the presence or absence of diabetic microvascular complications. Clinical data such as sex, age, history of hypertension, and course of diabetes were collected. Height and weight were measured, Body Mass Index (BMI) was calculated, and systolic and diastolic blood pressure were measured.

After fasting for 8-12 hours, 5 ml of venous blood was drawn, and concentrations of the following entities were measured: glycosylated hemoglobin (HbA1c), fasting blood glucose, homocysteine, uric acid, cystatin C, cholesterol, triglycerides, low, high-density lipoprotein cholesterol, serum creatinine and calculated eGFR (CKD-EPI method). Urine microalbumin/urine creatinine; Fasting C-peptide; Antithyroid peroxidase antibody, thyroglobulin antibody, serum Free Triiodothyronine (FT3), serum Free Thyroxine (FT4) and Thyroid-Stimulating Hormone (TSH) were also measured (Chemiluminescence).

FT3 and FT4 were divided into AFT3, BFT3 and AFT4, BFT4 groups with the median as the cut-off point respectively. (The truncation values were 2.69 pg/ml and 0.98 ng/dl, respectively). TSH were used to divide the patients into ATSH and BTSH groups with 2.5uIU/ml as the cut-off point. The cut-off value for substandard HbA1c is set at 6.5% [2].

Statistical Processing

SPSS 23.0 software was used for statistical analysis. Normal distribution measurements are expressed as mean ± standard deviations, and independent sample t-tests are used for intergroup comparisons. Nonnormal distribution measurements are expressed as medians and two-percentile spacing [M (QL, QU)], Nonparametric tests are used. Counting data are expressed as n (%), using a chi-square test. Logistic regression was used to analyze the relationship between thyroid hormones and microvascular complications of diabetes.

Results

1.The comparison of general clinical data of each group of patients

2.The prevalence of microvascular complications at different thyroid hormone concentrations (Figure 1-3).