Many articles are written on cardiovascular disease and diabetes because we as a group are at high risk for morbidity and mortality from cardiovascular complications. How can it be that only 1/3 of diabetics realize this fact as reported in one of our abstracts this month?
Complications of atherosclerosis are responsible for about 80% of deaths in diabetic persons and 75% of hospitalizations for diabetic complications. In the 7-year Finnish study it was found that the absolute risk for major cardiac events in type 2 patients without known coronary artery disease (CAD) was 20.2% compared to 18.8% in matched nondiabetic patients who had established CAD.
Even before one experiences hyperglycemia, persons with impaired glucose tolerance have an elevated risk for macrovascular disease. To make matters worse, 59% of patients have evidence of cardiovascular disease at he time of diagnosis of type 2 diabetes. And, although the mortality rate due to cardiovascular disease has continued to decline in nondiabetic people in the last 25 years, it has remained steady or increased in the diabetic population.
People with diabetes also have a higher risk of death before and after infarction as well as increased incidence of congestive heart failure. The usual sex differences of prevalence of CAD are reversed in people with diabetes. The risk ratio for increased mortality is 2.4 for diabetic men and 3.5 for diabetic women.
It is very important that your physician take these facts into account when treating you, and when evaluating or treating cardiovascular disease in female diabetic patients. We know these facts are hard to digest if you or a loved one has diabetes, but please read on.
We used to tell children who had difficulty protecting themselves this fact. People think that ostriches hide their heads in the earth when they are afraid. The truth is that they share their environment with many predators and there would be few to no ostriches if this were true.
What they do is to graze on vegetation which because of their long legs and necks makes them look like they may be hiding. No way. Please don’t let your loved ones or you hide.
First look at the major risk factors in diabetic patients all of which can be addressed by you and your physicians. This is our “first” through “eleventh” ways to cut your risk factor. Check them all with your physician or health team:
- Cigarette smoking: Stop smoking. Your physician should ask you at every visit if you smoke and cautiously prescribe nicotine replacement.
- Hypertension: ADA/AHA, <130/85 mm Hg National Kidney Foundation, <130/80mm Hg. Measure blood pressure yearly to detect orthostatic hypotension; consider home monitoring.
- Hyperlipidemia: Priorities: 1, LDL cholesterol < 100mg/dl; treat with statins and resins. 2, Triglycerides <200 mg/dl (aggressive, 125 mg/dl); maintain glycemic control, prescribe fibrate therapy and review alcohol and estrogen use. 3, HDL cholesterol> 45 mg/dl; recommend exercise, weight loss, and estrogen therapy for women.
- Hyperglycemia: Target hemoglobin A1c <7% has been proven to reduce microvascular complications, but <6% may be needed to prevent macrovascular complications.
- Weight: Body mass index <27. Provide nutrition and exercise counseling.
- Urine microalbumin: Test yearly; if result is positive, begin ACE inhibitor even in normotensive patients.
- Retinal complications: Perform dilated examination yearly.
- Coagulation: Prescribe aspirin (80-325mg/day) unless contraindicated.
- Infectious disease: Maintain influenza and pneumocochal immunization.
- Dental complications: Recommend yearly examination.
- Foot complications: perform bi-annual foot examination, i.e., physical inspection. measurement of petal pulses dm sensation testing ( with 5.07 mm monofilament).
There are three other factors that may affect the accelerated atherogenic process in persons with type 2 diabetes. Although lab tests are not currently done on a routine basis, you will want to know your risk factors and talk to your physician about these. Awareness of these factors and appropriate intervention can help reduce cardiovascular risk in diabetic persons.
- C-reactive protein: Diabetes may lead to a chronic, low-grade inflammatory state possibly cased by glycosylation of proteins that activate macrophages, or by increased oxidative stress. A marker for systemic inflammation is C-reactive protein, an acute phase reactant. In the Physicians’ Health Study, C-reactive protein level was found to be the best predictor of first myocardial infarction in healthy middle-aged men. Levels of C-reactive protein are elevated in patients with type 1 diabetes without macrovascular disease, which suggests that inflammation may precede atherosclerosis in diabetic patients. The high cardiovascular risk associated with elevations in C-reactive protein can be negated by treatment with pravastatin (Pravachol) or buffered aspirin in nondiabetic populations. The US Food and Drug Administration recently approved a highly sensitive assay for C-reactive protein, however, routine screening is currently not supported.
- Plasminogen activator inhibitor-1: The balance of clot formation and dissolution is altered in diabetic persons who have increased clot formation and “sticky” platelets as well as decreased clot breakdown due to altered fibrinolysis. This state leads to increased clot stability and propagation and is associated with increased risk of cardiovascular events. Recent research shows that elevated levels of plasminogen activator inhibitor-1 (PAI-1) in persons with insulin resistance increases the risk of acute cardiac events by inhibiting fibrinolysis. Improved glycemic control alone or treatment with metformin (Glucophage) and pioglitazone hydrochloride (Actos) can decrease PAI-1 levels and may reduce cardiovascular risk. Routine PAI-1 screening cannot be fully supported because of lack of standardized assays.
- Hyperhomocystinemia: Homocysteine, a metabolite of methionine, is highly reactive in high concentrations and may directly damage the endothelium. Both type 1 and type2 diabetics have been shown to have elevated homocysteine levels, although no studies to date have shown reduced risk for CAD with reduction in homocysteine levels. Routine monitoring in diabetic persons is not yet recommended. Studies in nondiabetic at-risk patients with homocysteine levels higher than 15 umol/L have shown benefit from treatment with folic acid.
We know that endothelial dysfunction, which is an imbalance between vasoprotective and proatherosclerotic factors in the level of the vascular endothelium is a contributor to accelerated atherosclerosis in diabetes.
Defects in endothelial functions are believed to be one of the earliest function abnormalities in the vascular wall and may provide the link between the microvascular and macrovascular complications of diabetes. Along with C-reactive protein markers discussed above, microalbuminuria may be early signs.
Urine microalbumin has also been associated with an increased risk of cardiovascular disease, likely due to endothelial disease that is localized in the kidney or its system. The MICRO-HOPE study showed that in diabetic patients at high risk, treatment with an angiotensin-converting enzyme inhibitor markedly reduced risk of cardiovascular disease without having a major effect on blood pressure, possibly through a reduction in endothelial dysfunction.
It is important to note that 80% of diabetic patients die of macrovascular complications, including CAD, stroke, and peripheral vascular disease. Because of the growing numbers of diabetic patients and the increased mortality after their first cardiovascular event, it is critical to identify and treat risk factors early and aggressively.
Numerous studies of patients with type 2 diabetes have shown the benefits of aggressive treatment of blood pressure and lipids to levels that 10 years ago would have seemed abnormally low. Although these downward changes in “normal” limits can be frustrating, it is necessary to aim for these levels to avoid complications in us, a very high-risk population.
Please read all you can and ask questions when you visit your physician. Don’t be like the caricature of that ostrich. Remember, there are lots of these regal birds, so for sure they do not bury their heads in the ground.