Heart disease is a health concern for everyone, but it should especially concern people with diabetes. Alan Marcus, MD, a diabetes expert on DIABETES HEALTH’s medical advisory board, says people with diabetes are at special risk for heart disease and should be careful to control high cholestrol and blood pressure levels with the right drugs.
Don’t Blame the Patient
Dr. Marcus stresses that the basic rule for any patient to remember when seeing a physician is that the patient is not to be blamed for having the symptoms of a chronic disease. Whether it’s high blood glucose, high blood pressure, high cholesterol, or any other problem associated with a chronic disease, the physician’s job is to help the patient control the symptom and achieve better health.
Controlling blood glucose levels alone is not enough to avoid cardiovascular disease. High cholesterol and high blood pressure are the major causes of hardening of the arteries and heart disease. Treatment of hyperlipidemia (elevated cholesterol) and hypertension (elevated blood pressure) are important for people with diabetes to reduce the risk of mortality.
Here are some sobering statistics:
- High blood pressure is twice as common in people with diabetes.
- Fifty percent of people with diabetes already have hardening of the arteries at the time of their diabetes diagnosis. Eighty percent of people with diabetes die of hardening of the arteries.
- If you have type I diabetes, high blood pressure usually occurs at the onset of diabetes, is normalized, and returns five to ten years later. If you have type 2 diabetes, high blood pressure can occur at any time. And by the time you’ve been diagnosed with type 2 you may have had the disease for five to ten years and already developed nerve damage, hardening of the arteries, high blood pressure, and high cholesterol.”
- Diabetic nephropathy (kidney disease) is the leading cause of renal failure and kidney damage. It is a direct result of high blood pressure and develops in forty percent of people with diabetes.
High Blood Pressure
High blood pressure is a consequence of having diabetes, but you can treat and prevent it, much as you can lower you blood sugar.
The goal is to lower systolic and diastolic blood pressure. To do this you need medication, probably more than one. But it is important to take the right medication, one that will reduce high blood pressure without causing other diabetes complications.
Your systolic blood pressure should be 135 or less, your diastolic blood pressure should be 85 or less, and if you have kidney disease, your diastolic blood pressure should be as low as possible in order to reduce kidney damage.
Hardening of the Arteries
The other major factor in developing coronary heart disease is hardening of the arteries. It can cause strokes, intermittent claudication (pain and limping caused by the narrowing of the arteries in the muscles), and heart attacks. Hardening of the arteries is caused by high cholesterol levels.
There are two types of cholesterol-“good” cholesterol and “bad” cholesterol.
HDL, good cholesterol, removes cholesterol buildup from arterial walls.
LDL, bad cholesterol, deposits cholesterol on arterial walls causing narrowing of the arteries. Also, excess LDL can indirectly lead to artery spasm. Normally, there is a factor in the blood vessels that opens the blood vessel walls when stress or other conditions trigger a release of adrenaline. Without this factor, the vessel wall constricts. LDL decreases this factor (called endothelial derived relaxing factor) by causing damage to the blood vessel lining (endothelium).
This is crucial because people don’t die of progressive narrowing of the blood vessel; they die of coronary artery spasm. Most people die with no greater than 40% blockage of an artery. It’s the spasm that closes the artery, and the LDL that indirectly causes the spasm.
Worse, if you have high blood glucose or high triglycerides, LDL1 is changed into LDL2, a much more toxic LDL than the regular bad cholesterol.
You should know your HDL, LDL, triglyceride, and total cholesterol numbers. Don’t let your doctor give you an “average” cholesterol number or a “risk-ratio.” These are of no importance.
What are your risk factors for hardening of the arteries?
Your unmodifiable risk factors are:
- Age (male over 45 years; female over 55, or with premature menopause without estrogen replacement therapy)
- Family history of premature coronary heart disease
- HDL-C levels less than 35 mg/dl
Your modifiable risk factors are:
- High cholesterol
- High blood pressure
Your HDL cholesterol should be greater than 35, your LDL cholesterol should be less than 130. And your LDL should be less than 100 if you already have hardening of the arteries, angina, claudication, or strong family history of heart attacks or strokes. Unfortunately, it is difficult to increase HDL more than ten percent.
If you already have high cholesterol, what do you do?
Marcus disagrees with the National Cholesterol Education Panel’s recommendation for people with high cholesterol-go on a diet and don’t eat fats.
While he doesn’t have a problem with the diet itself, Marcus has performed studies that show less than five percent of people on diets are successful in lowering cholesterol. Furthermore, the studies show that even when patients lower cholesterol through diet, their risk of mortality is not reduced.
“Diets alone won’t work. In many situations, drugs are the answer,” says Marcus.
There are many drugs that work to reduce both high blood pressure and high cholesterol. Some are better than others for people with diabetes.
Antihypertensive drugs reduce high blood pressure. The ones that have neutral or favorable effects on cholesterol levels and which are considered safe for people with diabetes are calcium channel blockers (CCBs), i.e. diltiazem verapamil, and diltiazem, angiotensin converting enzyme inhibitors (ACEIs), i.e. enalapril, captopril, lisinopril, and quinapril, and alpha-blockers, i.e. doxazosin mesylate.
Marcus believes the ACEIs, such as captopril, are the best anti-hypertensive for people with diabetes. They prevent diabetic kidney disease and may even reverse it. And if you have a heart attack, they prevent you from dying or from having a second heart attack.
Marcus says ACEIs are currently underused. The Wall Street Journal recently reported that only five percent of the people who could benefit from them are taking them.
CCBs are also excellent. They help with heart disease, they help prevent kidney disease, and they don’t make diabetes worse.
Alpha blockers are also good. They act favorably to decrease triglycerides and cause a small increase in HDL.
Antihypertensives that are not as good for patients who already have elevated cholesterol levels and arteriosclerosis are Beta-blockers (non-ISA) and diuretic antihypertensives. They increase LDL and triglycerides and reduce HDL. Also, for diabetic patients, thiazides and beta-clockers are less desirable because they impair insulin sensitivity.
A study reported in the New England Journal of Medicine found that hydrochlorothiazide, a thiazide antihypertensive which is a diuretic, taken at more than 25 mgs per day normalized blood pressure but also increased the risk of dying four times compared to patients not on medication. Because it increases glucose and cholesterol levels and worsens insulin resistance when taken at the level necessary to reduce blood pressure, it is not ideal for people with diabetes. It also has a negative effect on electrolytes such as potassium and magnesium.
The Lipid Modifying Drugs
These are the drugs which work to reduce bad cholesterol and triglycerides and increase good cholesterol. Not all, according to Marcus, are wholly beneficial for people with diabetes.
Resins (Bile Acid Sequestrants), such as cholestyramine and colestipol, lower LDL cholesterol and reduce the risk of coronary heart disease. However, they should not be taken by anyone with a triglycerides level of over 200 mg/dl.
The HMG-CoA reductase inhibitors (Statins), such as lovastatin, simvastatin, pravastatin, and fluvastatin, lower LDL by 20-40%, and reduce the chance of heart attack from 40-60%. They reduce the risk of coronary heart disease and lower the death rate from myocardial infarctions. Also, they increase the factor that causes blood vessels to open rather than constrict.
Marcus considers Statins an excellent drug, but they are expensive, and HMOs are not always willing to pay for them.
A potentially damaging drug for people with diabetes, according to Marcus, is Niacin (nicotinic acid). It reduces the risk of coronary heart disease, but it increases glucose levels. And although it lowers lipids, if you have diabetes it gives you increased risk for liver disease.
To know if you should be considering heart disease medications, you need to know what your blood pressure and cholesterol levels are. The ADA says you should have the following tests at least once a year: fasting lipid profile, total cholesterol, HDL, LDL, triglyceride, and a 24 hour urine test for protein and creatinine clearance.
Get tested, and then get the medicines you need.
This information is taken from a talk presented at “Taking Control of Your Diabetes,” a one-day “motivational conference and health fair” which took place in San Diego on September 23, 1995. Directed by Steven V. Edelman, MD, and facilitated by an impressive faculty of diabetes physicians, educators, researchers, and advocates, the conference addressed many important issues for people with diabetes. The conference was sponsored by the UCSD School of Medicine, The Whittier Institute for Diabetes, and the Veterans Affairs Center. Audio tapes of portions of the conference may be ordered by calling the Sound of Knowledge, Inc. at (619) 483- 4300.