The HOMA-IR index is used to measure insulin resistance, an early stage of type 2 diabetes that increases the risk of many chronic diseases. The HOMA-IR (Homeostasis Model Assessment – Insulin Resistance) index practically says how much insulin the body needs to keep blood sugar levels in check.
Insulin resistance and the metabolic abnormalities related to insulin resistance have been associated with metabolic syndrome, type 2 diabetes mellitus, and cardiovascular diseases in adults and in the elderly. Metabolic syndrome is now increasingly being recognized in children and adolescents. Childhood obesity is well known for its association with insulin resistance.
Insulin resistance is typically defined as decreased sensitivity or responsiveness to the metabolic actions of insulin, such as insulin-mediated glucose disposal and inhibition of hepatic glucose production. There are various clinical-laboratory tools used to quantify insulin sensitivity and resistance directly (hyperinsulinemic-euglycemic glucose clamping) and indirectly (intravenous glucose tolerance test) and are used as reference methods. However, these methods are very difficult and expensive to apply in clinical practice, and for these reasons alternative ways of assessing insulin resistance, such as the HOMA-IR index, have been devised.
Insulin, a hormone secreted by the pancreas, helps the body use glucose for fuel. When the body becomes insulin resistant, the pancreas will increase its production of insulin to compensate, but increased levels of insulin can damage the overall health and make it very difficult to lose weight. If insulin resistance is left untreated, it can lead to the development of pre-diabetes, type 2 diabetes mellitus, or other metabolic conditions, like heart disease and fatty liver disease.
When insulin resistance is identified early, it can be reversed. That is why using the HOMA-IR to identify subtle insulin resistance, even before it is evident in more traditional screening measures like hemoglobin A1c (HbA1c) and fasting blood sugar.
The HOMA-IR index is a validated, non-invasive laboratory tool to assess the relationship between glucose and insulin. If elevated, it can guide the patient to make diet and lifestyle changes that will bring the HOMA-IR score down into the insulin-sensitive range, lose weight, and improve overall health.
What is insulin resistance?
People with insulin resistance, also known as impaired insulin sensitivity, have built up a tolerance to insulin, making the hormone less effective. As a result, more insulin is needed to persuade fat and muscle cells to take up glucose and the liver to continue to store it.
Just why a person fails to respond properly to insulin is still a mystery. In response to the body's insulin resistance, the pancreas deploys greater amounts of the hormone to keep cells energized and blood glucose levels under control. Therefore, people with type 2 diabetes tend to have elevated levels of circulating insulin. The ability of the pancreas to increase insulin production means that insulin resistance alone won't have any symptoms at first. Over time, though, insulin resistance tends to get worse, and the pancreatic beta cells that make insulin can wear out. Eventually, the pancreas no longer produces enough insulin to overcome the cells' resistance. The result is higher blood glucose levels and ultimately type 2 diabetes.
Insulin has other roles in the body besides regulating blood glucose levels, and the effects of insulin resistance are thought to go beyond diabetes. For example, some research has shown that insulin resistance, independent of diabetes, is associated with heart disease.
What causes insulin resistance?
Several genes have been identified that make a person more or less likely to develop the condition. It's also known that older people are more prone to insulin resistance. Lifestyle can play a role, too. Being sedentary, overweight, or obese increases the risk of insulin resistance. Some researchers theorize that extra fat tissue may cause inflammation, physiological stress, or other changes in the cells that contribute to insulin resistance. There may even be some undiscovered factor produced by fat tissue, perhaps a hormone, that signals the body to become insulin resistant.