Insulin resistance and influencing factors of patients with hypothyroidism

Abstract

Objective To investigate the changes in glucose and lipid metabolism, insulin resistance in patients with hypothyroidism and analyze the influencing factors. Methods A total of 125 patients with hypothyroidism in the First Affiliated Hospital of Zhengzhou University from March 2017 to March 2018 were selected as observation group. Sixty healthy individuals were selected as control group. The differences in the general information, the fasting blood glucose (FBG), fasting insulin (FINS), 2 h postprandial glucose (2 h BG), 2 h postprandial insulin (2 h INS), homeostasis model of assessment for insulin resistance index (HOMA-IR), insulin sensitivity index (ISI), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) were compared between the two groups. Pearson correlation analysis was applied to analyse the relationship between HOMA-IR and other indicators. The influencing factors of insulin resistance in patients with hypothyroidism were analyzed by Logistic regression analysis. Receiver operator characteristic (ROC) curve was drawn to determine the cut-off point of thyroid stimulating hormone (TSH) for detecting insulin resistance in patients with hypothyroidism. Results Body mass index (BMI), FBG, FINS, 2 h INS, HOMA-IR, TC, TG, LDL-C in observation group were significantly higher than those in control group (P<0.05), while ISI, HDL-C were significantly lower than those in control group (P<0.05). HOMA-IR was negatively correlated with free thyroxine 4 (FT4) and ISI (r=-0.278, -0.599, P<0.05), and positively correlated with BMI, TSH, FBG, TC, LDL-C (r=0.367, 0.456, 0.365, 0.270, 0.295, P<0.05). TSH (OR=1.040, 95%CI 1.004-1.078, P<0.05) was an independent risk factor of insulin resistance in hypothyroidism patients without consideration with gender, age, BMI, FT4, TC and LDL-C. The optimal cut-off point of TSH for detecting insulin resistance in patients with hypothyroidism was 10.11 μU/ml with the sensitivity of 94.7% and specificity of 58.9%. Conclusions The patients with hypothyroidism are more likely to develop hyperglycemia, hyperlipidemia and insulin resistance than healthy people. TSH is an independent risk factor of insulin resistance in hypothyroidism patients. When TSH is more than 10.11 μU/ml, the glucose and lipid metabolism indicators should be monitored as early as possible to identify glucose and lipid metabolism dysfunction to reduce the occurrence of related diseases. Key words: Hypothyroidism; Insulin resistance; Influencing factors