Associations among Insulin Resistance, Triacylglycerol/High Density Lipoprotein (TAG/HDL ratio) and Thyroid hormone levels-A study on Type 2 diabetes mellitus in obese and overweight subjects.

AIM: Triacylglycerol/High density lipoprotein (TAG/HDL) ratio, a surrogate marker of LDL particle size (small dense) was included in our study to observe the link with insulin resistance and thyroid co-morbidity.

METHODS

Ninety three patients with T2DM of both genders were enrolled from a tertiary health care unit in Puducherry, during the latter half of 2015. The cardio-metabolic risk factors were assessed through body mass index (BMI), blood pressure, fasting blood glucose and lipid profile, glycated haemoglobin and homeostasis model assessment of insulin resistance (HOMA-IR). Serum free T4, T3 and TSH were also measured to evaluate the thyroid co-morbidity as a function of insulin resistance.

RESULTS

In addition to insulin resistance, results of our study were focussed on thyroid comorbidity. In overweight diabetic patients, the ROC curve analyses demonstrated that the best marker for insulin resistance was Triacylglycerol/High density lipoprotein (TAG/HDL), with the area under the ROC curve being 0.902. Thyroxine (T4) was less significant when compared to TAG/HDL with area under the ROC curve of 0.583. Triiodothyronine (T3) and T4 were more significant in obese group with areas under the curve being 0.842 and 0.816 respectively when compared against insulin resistance (cut-off value for HOMA-IR 2.69). The optimal cut-off points for overweight were: TAG≥101mg/dl; T4≥1.16ng/dl; TAG/HDL≥2.26 whereas for obese: TC≥163.5mg/dl; TAG≥141.5mg/dl; T3≥2.42pg/ml; T4≥0.96ng/ml.

CONCLUSIONS

In overweight type 2 diabetics, TAG/HDL ratio could be used as a reliable marker for insulin resistance with thyroid co-morbidity and T3, T4 were better objective markers in obese type 2 diabetics.