Diabetes & the Heart

Prevention of coronary heart disease.

Definitions:

Levels of Evidence

1. Strong research-based evidence. Multiple relevant, high-quality scientific studies with homogenic results.

2. Moderate research-based evidence. At least one relevant, high-quality study or multiple adequate studies.

3. Limited research-based evidence. At least one adequate scientific study.

4. No scientific evidence. Expert panel evaluation of other information.

MAJOR RECOMMENDATIONS :

1. Medical Priorities

   In the context of a comprehensive population strategy -- to reduce tobacco use, encourage healthy food choices and increase physical activity for the whole population -- the medical priority is to focus on those who have developed symptoms of coronary heart disease or other major atherosclerotic disease, and those who are at high risk of developing such diseases in the future.
   
   A. The priorities for preventive cardiology are:
    

   1. Patients with established coronary heart disease or other atherosclerotic disease.

   2. Healthy individuals who are at high risk of developing coronary heart disease or other atherosclerotic disease, because of a combination of risk factors -- including smoking, raised blood pressure, lipids (raised total cholesterol and low density lipoprotein (LDL)-cholesterol, low high density lipoprotein (HDL)-cholesterol and raised triglycerides) raised blood glucose, family history of premature coronary disease -- or who have severe hypercholesterolemia or other forms of dyslipidemia, hypertension or diabetes.

   3. Close relatives of patients with early onset coronary heart disease or other atherosclerotic disease, and of healthy individuals at particularly high risk.

   4. Other individuals met in connection with ordinary clinical practice.

   
   
    

2. Objectives of Coronary Heart Disease Prevention

   The overall objective of coronary heart disease prevention, both in patients with clinically established coronary heart disease, or other atherosclerotic disease, and high risk individuals is the same: to reduce the risk of major coronary heart disease or other atherosclerotic disease events, and thereby reduce premature disability, mortality and prolong survival. In these recommendations goals have been set not only for lifestyle change but for the management of blood pressure, blood lipids and diabetes in secondary and primary prevention of coronary disease.
   
   
    

3. Absolute Multifactorial Coronary Heart Disease Risk As A Guide To Lifestyle Intervention And Drug Treatments

   Patients who present with symptoms of coronary heart disease, or other atherosclerotic disease, declare themselves to be at very high absolute risk of a further vascular event. Therefore they require the most intensive lifestyle intervention and, as necessary, drug therapies in order to achieve risk factor goals.
   
   As coronary heart disease is multifactorial in origin it is important in healthy individuals to estimate absolute risk (the risk of developing coronary heart disease either a non-fatal event or coronary death, over the next 10 years) by taking into account the major risk factors. Those at highest multifactorial risk can be identified and targeted for lifestyle interventions and, where appropriate, drug therapies. Physicians should always use absolute coronary heart disease risk when making clinical judgment about using drugs to treat blood pressure, and blood lipids, rather than just considering the level of any one risk factor alone. An absolute coronary heart disease risk which exceeds 20% over the next 10 years, or will exceed 20% if projected to age 60, and which is sustained despite professional lifestyle intervention, is sufficiently high to justify the selective use of proven drug therapies.

4. Secondary Prevention

   A. Patients with coronary heart disease or other atherosclerotic disease:

   1. Lifestyle.
      
      Lifestyle changes depend on the readiness of coronary and other high risk patients to modify their behavior. When patients develop symptoms of coronary heart disease, or are found to be at high risk, this is an ideal opportunity to review lifestyle. Many will consider making appropriate changes and, with professional and family support, can do so for life.
      
       

   2. Stop smoking tobacco.
      
      Patients should be professionally encouraged and supported to stop smoking all forms of tobacco for life. A physician can, with sustained advice, help patients to quit. Avoidance of passive smoking would also be prudent. Nicotine replacement therapies can be initially helpful for some patients, particularly those who are heavily addicted to nicotine. Other family members sharing the same household can support patients to stop smoking, and reduce the risks of taking up this habit again by not smoking themselves.
      
       

   3. Make healthy food choices.
      
      All patients should receive professional advise on food and food choices which make up a diet associated with the lowest risk of coronary heart disease or other atherosclerotic disease. Physicians should emphasize the importance of diet in relation to weight reduction, lowering blood pressure and blood cholesterol, in the control of blood glucose in diabetic patients and in reducing the propensity to thrombosis. Diet is an integral part of the patient's overall management. The role of the family is particularly important in this context as the person primarily responsible for buying and preparing food must be informed of the need for healthy food choices and how these can be practically achieved. The relevance of physical activity in helping weight control and favorably modifying other risk factors should be explained. Many dietary factors are related to the risk of coronary heart disease and other atherosclerotic disease. For a patient with atherosclerotic disease the dietetic goals are :
      
       

      • To reduce total fat intake to 30% or less of total energy intake, the intake of saturated fat to no more than one third of the total fat intake, and the intake of cholesterol to less than 300 mg/day.

      • To achieve the reduction in saturated fats by replacing them in part with monounsaturated and polyunsaturated fats from both vegetable and marine sources, as well as with complex carbohydrates.

      • To increase the intake of fresh fruits, cereals and vegetables.

      • To reduce total calorie intake when weight reduction is needed.

      • To reduce salt and alcohol use when blood pressure is elevated.

      
      
      Patients who have hypertension, hypercholesterolemia or other forms of dyslipidaemia or diabetes can benefit from specialist dietary advice. Appropriate dietary changes can favorably influence all these risk factors, and reduce the need for drug therapies.
      
       

   4. Increase physical activity.
      
      All patients should be professionally encouraged and supported to increase their physical activity safely to a level associated with the lowest risk of vascular disease. Aerobic exercise (e.g., walking, swimming, or bicycling) for 20-30 min 4-5 times a week is recommended. Physicians should emphasize the importance of physical activity in giving the patient a sense of well being. Being physically active helps to reduce weight (together with healthy food choices), increase HDL cholesterol, lower triglycerides and the propensity to thrombosis. Once again the family is important in supporting an active lifestyle.
      
       

   B. Other cardiovascular risk factors:

   3. Overweight and obesity.
   
   Patients who are overweight (body mass index (BMI) >25 kg/m) or obese (BMI >30 kg/m), and particularly those who have central obesity, are at increased risk and should be professionally supported to lose weight using an appropriate diet and increased physical activity. Weight reduction will also help to reduce blood pressure, blood cholesterol and blood glucose. Waist circumference is a useful clinical index of obesity and for monitoring weight reduction. A waist circumference >94 cm in men and >80 cm in women is an indication to lose weight and >102 cm in men and >88 cm in women requires professional advice on weight reduction.
   
   4. Blood pressure.
   
   In coronary patients the blood pressure goal is consistently below 140/90 mmHg. If this goal is not achieved with lifestyle changes, drug therapy should be used. For patients with angina preference should be given to beta-blockers, or if not tolerated or effective, to long-acting calcium channel blockers, as both drug classes will lower blood pressure and relieve symptoms. Following acute myocardial infarction preference should be given to beta-blockers as this drug class will also reduce risk of recurrent disease. Angiotensin converting enzyme (ACE) inhibitors can also be used particularly in patients with significant left ventricular systolic dysfunction.
   
   5. Blood lipids.
   
   The blood cholesterol goals are a total cholesterol consistently below 5.0 mmol/l (190 mg/dl), and an LDL cholesterol below 3.0 mmol/l (115 mg/dl). Concentrations of HDL cholesterol and triglycerides are not used as goals of therapy. However, an HDL cholesterol <1.0 mmol/l (40 mg/dl) and fasting triglycerides >2.0 mmol/l (180 mg/dl) are markers of increased coronary risk. If the total and LDL cholesterol goals are not achieved with lifestyle changes then drug therapy should be used. Preference should be given to HMG Co-A reductase inhibitors (statins) as this class of lipid lowering drugs has the strongest evidence in coronary heart disease patients for reducing coronary morbidity, mortality, and prolonging survival. There is also evidence that statins will reduce the risk of stroke in coronary patients.
   
   6. Blood glucose.
   
   Although it is not known whether good blood glucose control reduces the risk of recurrent disease in diabetic patients with coronary heart disease or other atherosclerotic disease, it does favorably influence microvascular disease and other diabetic complications. The goals for adequate glucose control in Type 1 (insulin-dependent) diabetes are: fasting blood glucose 5.1-6.5 mmol/l (91-120 mg/dl); post-prandial (peak) glucose; 7.6-9.0 mmol/l (136-160 mg/dl); HbA1C 6.2-7.5%; and avoidance of serious hypoglycemias. In the majority of patients with type 2 (non-insulin-dependent) diabetes even lower goals, extending to the non-diabetic range, can be safely achieved. For some patients, particularly the elderly, less stringent goals have to be accepted.
   
   7. Other prophylactic drug therapies.
   
   In addition to drugs needed to supplement lifestyle management of blood pressure, lipids and glucose the following drug classes, which can each reduce morbidity and mortality in coronary heart disease patients, should also be considered.
   
    

   • Aspirin (at least 75 mg), or other platelet modifying drugs, in virtually all patients.

   • Beta-blockers in patients following acute myocardial infarction.

   • ACE inhibitors in patients with symptoms or signs of heart failure at the time of myocardial infarction, or with persistent left ventricular systolic dysfunction (ejection fraction <40%).

   • Anticoagulants following myocardial infarction for selected patients at increased risk of thromboembolic events, including those with large anterior myocardial infarction, left ventricular aneurysm or thrombus, paroxysmal tachyarrhythmias, chronic heart failure and those with a history of thromboembolic events.

   
   
   8. Screen close relatives.
   
   Close relatives of patients with premature coronary heart disease (men <55 years and women <65 years) should be screened for coronary risk factors as they are at increased risk of developing coronary heart disease.
   
   
   
   

5. Primary Prevention
   
   Individuals at high risk of developing coronary heart disease or other major atherosclerotic disease:

   
   
   0. Estimation of coronary risk.
   
   The absolute risk of developing coronary heart disease (non-fatal coronary heart disease or coronary death) over the next 10 years can be estimated from the Coronary Risk Chart using gender, age, smoking status, systolic blood pressure and total cholesterol. For individuals whose absolute coronary heart disease risk is >20% over the next 10 years (or will exceed 20% if projected to age 60) intensive risk factor modification is recommended including, where appropriate, a selective use of proven drug therapies. Lifestyle intervention in this high-risk group is particularly important.
   
    

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   1. Lifestyle. .
      
      High risk individuals are especially encouraged to stop smoking, make healthier food choices and become physically active. Avoiding overweight, or reducing existing overweight, is important in primary prevention. With such lifestyle changes the need for lifelong drug therapy maybe obviated. Lifestyle recommendations given for coronary heart disease patients apply to these high risk individuals.
      
       

   2. Blood pressure. .
      
      Clinical trials of blood pressure lowering using different drugs have convincingly shown that the risks associated with rising blood pressure can be substantially reduced particularly for stroke, but also coronary heart disease and heart failure. This risk reduction is likely to be due to the common factor of lowering blood pressure rather than any intrinsic property of the classes of antihypertensive agents used. As coronary heart disease accounts for the largest proportion of deaths due to cardiovascular disease the primary consideration in blood pressure treatment is reducing coronary heart disease risk.
      
      A decision to treat blood pressure with drugs depends on the absolute coronary heart disease risk as well as systolic and diastolic pressure level, and target organ damage. For individuals with a sustained systolic blood pressure >180 mmHg and/or a diastolic >100 mmHg, despite lifestyle interventions, the risk of coronary heart disease, stroke and heart failure is so high that drug treatment is essential. Individuals with a systolic blood pressure (SBP) 160-179 mmHg and/or a diastolic blood pressure (DBP) between 95 and 99 mmHg often require drug treatment if these high blood pressure values are sustained. Those with more mild sustained blood pressure increases (SBP 140-159 and/or DBP 90-94 mmHg) may also require drug treatment but this will depend on the presence of other risk factors (an absolute coronary heart disease risk >20% over 10 years, or >20% if projected to age 60) and whether or not there is target organ damage. In contrast, at the same pressure levels drug will not usually be needed in someone who is at a lower absolute coronary heart disease risk.
      
      When starting blood pressure lowering therapy a treatment goal is set and the dose titrated up until it is achieved. Treatment is preferably started with one drug, and if necessary, a second or even third line anti-hypertensive agent is added to achieve the goal. A goal blood pressure clearly and consistently less than 140/90 mmHg is appropriate for primary prevention. For young individuals, patients with diabetes and for patients with renal parenchymal disease the blood pressure goal can be even lower.
      
      Reductions in cardiovascular morbidity and mortality by antihypertensive treatment with diuretic-based (particularly thiazides) and beta-blocker-based regimens is well established. Similar evidence has recently been obtained for some calcium channel blocker-based regimens. In some of these trials, however, ACE-inhibitors and other drugs have also been used in the treatment regiments. Therefore several classes of drugs can be considered for antihypertensive treatment with the goal of adequate blood pressure reduction.
      
       

   3. Blood lipids.
      
      Clinical trials of lipid modification by diet and different drugs have convincingly shown that coronary heart disease risk associated with rising cholesterol can be substantially reduced. This risk reduction is likely to be due to the common factor of modifying lipoproteins, principally lowering LDL cholesterol, rather than any intrinsic property of the lipid lowering agents used.
      
      A decision to treat blood lipids with drugs depends on the absolute coronary heart disease risk as well as lipid levels, lipoprotein profile and family history of premature coronary heart disease or other atherosclerotic disease. Patients with familial hypercholesterolemia are at such high coronary heart disease risk of premature coronary artery disease that drug treatment is always necessary. Individuals who are at high coronary heart disease risk because of a combination of risk factors (absolute coronary heart disease risk > 20% over 10 years, or > 20% if projected to age 60), and whose cholesterol levels are not lowered by diet, require drug treatment of blood lipids. For such high risk individuals the goals are a total cholesterol consistently below 5.0 mmol/l (190 mg/dl) and an LDL cholesterol below 3.0 mmol/l (115 mg/dl). This view is supported by primary prevention trials of cholesterol lowering therapies which have shown benefit by reducing coronary morbidity and mortality, when treating individuals with absolute coronary heart disease even lower that 20%. Concentrations of HDL cholesterol <1.0 mmol/l (40 mg/dl) and fasting triglycerides >2.0 mmol/l (180 mg/dl) are markers of increased coronary heart disease risk.
      
      When starting lipid-lowering therapy the drug dose should be titrated up until the cholesterol goal is achieved. It may not be possible for all high risk individuals to achieve this goal by diet, or with a lipid lowering drug at the maximum dose, and therefore some will need combination drug therapy. Those with very high cholesterol or LDL cholesterol levels may still not achieve this goal, even on maximum therapy, but will still benefit to the extent to which cholesterol has been lowered.
      
      There are four classes of drugs in current use (statins, fibrates, resins and niacin), and one or more drugs of each class has been shown to reduce coronary heart disease morbidity and mortality, but the evidence for efficacy and safety in primary prevention is strongest for the statins.
      
       

   4. Blood glucose..
      
      At present there is no trial evidence on blood glucose control and the risk of coronary heart disease or other atherosclerotic disease in diabetic patients. In both Type 1 and 2 diabetes the degree of hyperglycemia is associated with increased risk of atherosclerotic diseases. Good glucose control (as defined for patients with coronary heart disease) has beneficial effects on diabetic microvascular disease, and other diabetic complications, and thus this should be achieved, wherever possible, in all diabetics. At every level of a given risk factor -- smoking, blood pressure, and plasma lipids -- and with every combination of such risk factors, the total coronary heart disease risk of a diabetic patient is much higher than the risk of a comparable non-diabetic. Therefore, it is particularly important to achieve the risk factor goals in diabetic patients.
      
       

   5. Prophylactic drug therapies..
      
      Aspirin or other platelet modifying drugs are not usually indicated in the management of high risk individuals. There is evidence that low dose aspirin (75 mg) can reduce the risk of coronary heart disease in treated hypertensive patients whose blood pressure is well controlled, and in men at particularly high coronary heart disease risk. Prescribing aspirin to all high risk individuals is not recommended.
      
       

   6. Screen close relatives..
      
      Close relatives of patients who are suspected to have familial hypercholesterolemia, or other inherited dyslipidemia, should have their lipids measured