Taking A Closer Look At Insulin Resistance Syndrome
Their study also demonstrated that cardiovascular risk in young adulthood is highly correlated to the degree of adiposity.6 A fat rich-diet has been linked to insulin resistance syndrome. Park et. al., studied the relation between a chronic high fat diet and the incidence of insulin resistance syndrome — independent of obesity.7 They put 40 lab rats on a chronic high fat diet. They determined that visceral obesity is associated with insulin resistance. On the other hand, increased intake of complex carbohydrates, such as dietary fiber, appear to improve insulin action.8 The clinically apparent affects of insulin resistance syndrome include obesity, hypertension, dyslipidemia, hyperinsulinemia and hyperglycemia.9 Numerous studies have shown that insulin resistance syndrome correlates to an increased risk for developing cardiovascular complications.10-11 Stoney et. al., showed that insulin resistance is associated with dyslipidemia, which indeed increased the risk for coronary artery disease in women with type 2 diabetes.12 In addition, there is strong support in the literature that insulin resistance syndrome is a risk factor for heart disease in elderly men who have type 2 diabetes.13 What Are The Best Treatment Options? Medical management of diabetes, especially type 2 diabetes, chiefly consists of insulin and sulfonylureas. However, when insulin resistance syndrome is correlated with diabetes, the pharmacological management should target a different mechanism of action. Metformin is an oral hyperglycemic agent, which improves glucose tolerance in patients with diabetes. Therefore, Metformin lowers both basal and postprandial plasma glucose levels and targets the hepatic system for this effect.14 Unlike sulfonylureas, Metformin does not stimulate insulin production, but it does inhibit gluconeogenesis in the liver. Multiple studies have shown that Metformin has positive benefits, such as reducing HgA1c, preventing heart attack, and improving the survival rate of those who have type 2 diabetes.15 Thiazolidinediones (i.e. Avandia, Actos) are the other key class of drug treatment for insulin resistance syndrome. These drugs primarily act to decrease insulin resistance through improved sensitivity to insulin in muscle and adipose tissue. In higher dosages, thiazolidinediones also inhibit hepatic gluconeogenesis. Their unique mechanism of action depends on the presence of insulin for activity. Thiazolidinedione decreases hepatic glucose transport and increases insulin dependent glucose disposal in skeletal muscle. Its mechanism is also critical for controlling glucose and lipid metabolism.16 Literature supports that using thiazolidinediones significantly lowers circulating free fatty acid levels.17 Clearly, multi-drug therapy is the optimal way to manage diabetic patients with insulin resistance syndrome. This allows physicians to target multiple tissue levels and provides a comprehensive approach. It has been demonstrated that the combination of sulfonurea and Metformin decreased the HgA1c level 11 to 12 percent in just 13 weeks.18 In the United States, only 4 percent of patients with diabetes receive both insulin and oral hyperglycemics for their condition. However, given the facts of insulin resistance syndrome and the mechanism of its action, multi-drug therapy is clearly the optimal treatment option. Certainly, this medical treatment should be combined with the well-documented benefits of an appropriate diet and exercise program. In Conclusion Insulin resistance itself is an important risk factor for the development of hypercholesterolemia, hypertension, atherosclerotic heart disease, coronary heart disease, and chronic heart failure.19,20 New evidence suggests that young, obese children are at risk of developing insulin resistance syndrome many years before diabetes is even diagnosed. New “healthy living” programs in the home and school environment appear to be a key factor in preventing insulin resistance syndrome and the eventual onset of diabetes in this high-risk population. Mr. Yen is a first-year resident at the University of Texas Health Science Center at San Antonio. Dr. Steinberg is an Assistant Professor in the Department of Orthopaedics/Podiatry Service at the University of Texas Health Science Center. He is also the Medical Director of the Texas Diabetes Institute Podiatry Clinic.