Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) in the Diagnosis of Insulin Resistance and Prediabetes

Type 2 diabetes mellitus consists of metabolic disturbances characterised mainly characterized by hyperglycemia which usually result from the combination of resistance to insulin action, inadequate insulin secretion, and excessive or inappropriate glucagon secretion. In clinical practice its very difficult to establish how much part of this metabolic disturbances is due to lack of insulin and how much it is due to peripheral resistance to insulin. In many of the cases of type 2 diabetes mellitus metabolic syndrome is present for many years before development of full blown type 2 diabetes mellitus. Metabolic syndrome is a cluster of biochemical and physiological abnormalities associated with the development of cardiovascular disease and type 2 diabetes. Insulin resistance is one of the important determinants of development of metabolic syndrome and then type 2 diabetes mellitus. Insulin resistance is increasing in many parts of the world due to sedentary lifestyle, substance abuse, obesity and harmful food habits. Several methods including estimation of blood glucose and insulin levels during fasting or after oral or intravenous glucose overload, have been used. But due to the simplicity of its determination and calculation, insulin resistance assessment by the homeostatic assay (HOMA-IR) is becoming more popular technique in clinical practice as well as in various epidemiological studies. Unlike type 1 diabetes, type 2 diabetes mellitus is gradual in onset and its diagnosis is usually delayed for many years. Early treatment of hyperglycaemia, hyperlipidemia and other metabolic irregularities reduces the cardiovascular risk in these patients. But these benefits are usually denied to patients mainly due to delay in diagnosis. In fact many of the patients admitted with myocardial infarction are diagnosed with type 2 diabetes while in intensive care units for myocardial infarction. Unlike in type I diabetes mellitus where insulin is deficient consequent to immune mediated destruction of B cells in type 2 diabetes there is Insulin resistance. Insulin resistance in pre diabetic stages can be diagnosed by using various methods. Some simple methods, from which indices can be derived, have been validated. These indices are used depending upon whether they are to be used for epidemiological or clinical purposes. For clinical purposes Quantitative insulin sensitivity check index (QUICKI) and homeostasis model assessmentinsulin resistance (HOMA-IR) are most commonly used while for epidemiological purposes indices like Belfiore, Cederholm and Stumvoll index are suitable. This review explains the utility of homeostasis model assessmentinsulin resistance (HOMA-IR) for the diagnosis of insulin resistance which is hallmark of pre diabetic state. The purpose of this paper was to review the current information available about HOMA-IR and its use in pre diabetes.