The Insulin Resistance Syndrome
Jennifer B. Marks,MD
University of Miami
School of MedicineReprinted with permission from: The Monitor, Vol 1. Number 3, Spring 1996. A publication of the American Diabetes Association/Florida Affiliate, Inc./Southeast Region.
Abnormalities in glucose and lipid (blood fats) metabolism, obesity, and high blood pressure occur together commonly enough in the same individuals as to suggest that they are somehow interrelated. In fact, this cluster of abnormalities has come to be known as a syndrome, going by a variety of names, including Syndrome X, the Deadly Quartet, and the Insulin Resistance Syndrome. What seems to connect the various features of the syndrome together is something called insulin resistance: that is, a reduced sensitivity in the tissues of the body to the action of insuln, which is, importantly, to bring glucose into those tissues to be used as a source of energy. When insulin resistance, or reduced insulin sensistivy, exists, the body attempts to overcome this resistance by secreting more insulin from the pancreas. This compensatory state of hyperinsulinemia (high insulin levels in the blood) is felt to be a marker for the syndrome. The development of Type II, or non-insulin dependent, diabetes occurs when the pancreas fails to sustain this increase insulin secretion. It is not clear how insulin resistance contributes to the presence of high blood pressure, but it is clear that the high insulin levels resulting from insulin resistance contribute to abnormalites in blood lipids—cholesterol and triglycerides.
The importance of the Insulin Resistance Syndrome, or perhaps more accurately, "The Pluri-Metabolic Syndrome", lies in its consequences. The syndrome is typically characterized by varying degrees of glucose intolerance, abnormal cholesterol and/or triglyceride levels, high blood pressure, and upper body obesity, all independent risk factors for cardiac disease. If one includes along with the classic four features the commonly associated conditions of aging, sedentary lifestyle, stress, smoking, and a dose of genetic susceptibility, then a deadly web of increased cardiovascular (heart and blood vessels) disease risk is woven. In fact, the presence of any one major feature alone substantially increases the risk of heart disease, but when they occur together the risk is magnified way out of proportion at the contribution of any one single factor.
This point was strikingly demonstrated by the PROCAM (Prospective Cardiovascular Munster) Study, in which the relationship between various cardiac risk factors and the incidence of heart attack over a four year period was examined in 2,754 men aged 40-65 years. The results showed that the presence of diabetes or high blood pressure alone increased the risk of heart attack by 2.5 times. When both diabetes and high blood pressure were present, the risk was increased 8 times. An abnormal lipid profile increased the risk 16 times; when abnormal lipid levels were present with high blood pressure and/or diabetes, the risk was 20 times higher.
Treatment for the described metabolic syndrome therefore aims at treating all of: the features of the syndrome that exist in a given person.
The first step, then, is to identify those people who may be at risk for the insulin resistance syndrome—people who are overweight, those who have a parent or sibling with Type II diabetes, women who had diabetes which occurred during pregnancy.
The second step, once one feature of the syndrome is identified, is to look for the presence of others. So, if a patient has high blood pressure and is overweight, a search for diabetes and lipid abnormalities should be part of his or her comprehensive evaluation. And, it means prescribing treatment (appropriate not just for the primary problem) but treatment which will hopefully benefit, or at least not worsen, any of the other conditions which may also be present. We refer to this as multiple risk factor intervention—treatment aimed aggresively at reducing all cardiac risk factors which may exist.
Fortunately, this is easy! The same general recommendations that we give to a person who has Type II diabetes, for example, in terms of a diet low in fat and concentrated sweets, weight loss and maintenance of ideal body weight, regular exercise, cessation of smoking, and moderation of alcohol intake, are essentially the same recommendations we give to someone with high blood pressure, high cholesterol, or simple obesity. And, when pharmacological intervention is required, we can now choose between a variety of drugs—blood pressure medications which improve insulin sensitivity and have no adverse effects on blood lipids, blood sugar medicines which improve insulin sensitivity and blood lipid levels, blood pressure treatments which may be particularly beneficial for the kidneys of people with diabetes—and so on.
This approach to caring for people with the insulin resistance syndrome, that of comprehensive evaluation and risk factor management, is essential if we are to meet and overcome the real health danger which accompanies this constellation of metabolic abnormalities—cardiovascular disease.
Return to Main Page, Wound Care Institute Newsletter, Fall 1996
