4) DIABETES AND HEART DISEASE
a) Introduction
There is a difference in the terms "quality of life" and "length of life" and anyone with diabetes must consider the differences in the two terms. "Quality of life" is largely affected by so called "diabetic small blood vessel disease" (the technical term is "microvascular disease"), which causes blindness, nerve damage (impotence), kidney failure and cognitive decline (dementia and Alzheimer's disease). "Length of life" is largely affected by "diabetic large blood vessel disease" (the technical term is "macrovascular disease") which causes and accompanies "heart disease" and "stroke", plus a host of lesser known diseases such a peripheral arterial disease (PAD), which are all killers. So anyone with type 2 diabetes has to make a personal decision as to the emphasis they need and want. Are they interested in "quality of life", "length of life" or both? It makes a difference!
It is incorrect for a person with diabetes to assume he has "everything under control" if he just controls his blood sugar (this is known as "optimal glycemic control") via diet and drugs. Controlling blood sugar controls the small blood vessel disease but 70% to 80% of diabetes patients actually die from what is known as "large blood vessel disease" (the technical term is "macrovascular disease") , the part of diabetes that affects the large blood vessels of the body. This disease causes heart attacks, high blood presure, peripheral arterial disease, heart failure, strokes, pulmonary embolisms, etc. These are all killers. We'll use the term "heart disease" to describe this "large blood vessel disease". Blood sugar control is only one of many factors affecting heart disease. For this reason, controlling blood sugar is only one of many determinants of the life expectancy of a person with type 2 diabetes. Unfortunately many articles and books emphasis just this "optimal glycemic control" as the only way to control diabetes. A survey by the American Diabetes Association conducted by Roper ASW found that only 18% of all people with type 2 diabetes knew they had a greatly increased risk of heart disease. In technical terms:
A.M. Carter , P.J. Grant
"Diabetes mellitus is characterized by fasting hyperglycemia and the development of chronic vascular complications. While microvascular disease has been strongly related to glycemic control, the major cause of mortality in diabetes is due to macrovascular disease affecting the cardiac and cerebrovascular circulations, which appear to have a more complex pathogenesis. Diabetes is associated with a 3-5-fold increase in death from myocardial infarction and similar figures pertain to stroke. The processes involved in atherothrombotic disease are complex and include variation in lipid metabolism, vascular responses, cell/cell interactions, and in the fluid and cellular phases of coagulation and fibrinolysis. The complex interactions between all of these processes are crucially altered by the metabolic milieu that characterizes diabetes mellitus, tipping the delicate balance towards atheroma formation, platelet aggregation and thrombus formation."Philippe Passa (paraphrased)
"Type 2 diabetes is an important, independent risk factor for cardiovascular disease. In primary prevention in diabetic patients, antihypertensive treatment, aspirin and lipid-lowering intervention are effective at reducing the incidence of coronary heart disease although the beneficial effect of optimal glycemic control remains to be conclusively proven. Indeed, beta-blockers and lipid interventions are more effective in Type 2 diabetic patients than in non-diabetic patients with coronary artery disease."
The factors which are within the control of a person with type 2 diabetes and which affect the life expectancy are: 1, proper use of insulin, 2. blood pressure medication, 3. blood lipid control through diet and medications, 4. aerobic exercise, 5. weight control, 6. blood sugar control (diet and medication), in about that order, 1 being the most important. The factors which are within the control of a person with type 2 diabetes and which affect the quality of life are: 1. proper use of insulin, 2. weight control, 3. blood sugar control (diet and medication), 4. frequent exercise, 5. anaerobic exercise, in about that order. Note the differences in the two courses of action. Now if an individual wants both a long life and a high quality life, all eight factors need to be controlled.
Some extremely well done studies, such as the UKPDS study in Britain, show that tight control of glucose levels can reduce the risk of heart disease by up to 80%. The counterintuitive result in the British study was that life expectancy was not affected by close control of blood sugar levels while heart disease was affected by close control. A USA study of 10,251 individuals (ACCORD study) and an Australian study of 11,140 individuals (ADVANCE study) both showed that close control of blood sugar did not extend the life expectancy in type 2 diabetics. The ACCORD study actually showed a significant decrease in life expectancy with the drug regime in the ACCORD protocol.
Many studies which have factored out weight loss have shown weight loss to be more important in reducing large blood vessel "heart" disease than just blood sugar control. By the same token, there has been a multitude of research which has shown that large blood vessel "heart" disease tends to be directly correlated to the levels of A1c, even at relatively low non-diabetic blood sugar levels. But A1c tends also to be directly related to weight and visceral fat. It is thus easy to see the difficulty in separating out the effects of these variables. This is probably the reason for the confusing results shown in the UKPDS study. Studies which have used statistics to remove the effects of these "confounding" variables has invariably found body weight and visceral fat to be more important than blood sugar control in large blood vessel "heart" disease in type 2 diabetes. The reason for this is simply that fat cells have a double effect on heart disease. The fat cells both reduce insulin sensitivity AND they increase heart disease directly by increasing blood lipids and increasing blood pressure.
Type 2 diabetes is a causal agent for the large blood vessel "heart" disease AND the two seem to share the same causal agents. So diabetes is almost always accompanied by large blood vessel disease to such a degree that anyone with type 2 diabetes should think and act as though they already have heart disease, because they probably do! Indeed, if statistics were kept on heart disease and stroke deaths where the patient also had diabetes, diabetes would probably become much more prominent as a killer of Americans. Diabetes is currently sixth on the list of killers with 73,000 deaths per year attributed to it (some lists give diabetes its proper position at #3). Seventy five to eighty percent of persons with diabetes actually die of heart disease complications. Thus this number should actually be 365,000, which would make diabetes the third leading cause of death in the USA. Of course, since diabetes and heart disease actually appear to be caused by the same set of factors, it might be more accurate to state that the third leading cause of death in the USA is the combination of diabetes and heart disease. But then we can't recommend that any person concentrate only on extending their life and forget about the other factors. Being alive but blind and on dialysis is a very poor quality of life. For any type 2 diabetic controlling both blood sugar and heart disease risks is the optimum goal.
Current Chapter: 4) DIABETES AND HEART DISEASE
a) Introduction
b) Small Blood Vessel versus Large Blood Vessel Disease
c) Large Blood Vessel Mechanisms
d) Blood Lipid Chemistry
e) Diabetes and "Heart Failure"
f) Peripheral Arterial Disease (PAD)
g) Blood Proteins, Diabetes and Heart Disease
h) Genetic Risk Factors for Diabetes and Heart Disease
© Copyright 2009 All Rights Reserved.