Risk assessment of coronary heart disease (CHD) in the office

Risk assessment of coronary heart disease (CHD) in the office









Risk factors

Risk factors







General and individual risk scales

General and individual risk scales






Patients with diabetes

Patients with diabetes







Risk assessment at individual level

Risk assessment at individual level

In contrast to community-based public health interventions, clinicians are responsible for preventive advice for a particular patient. An important step in determining an individual preventive strategy is to assess the risk of developing a clinically significant outcome, because indicators of the cost-effectiveness ratio of any intervention vary depending on the overall risk of the individual or population.

Since the absolute risk in people with an established disease is high, in order to save one life or prevent one cardiovascular event (SSSob) among them, fewer people with high risk should be treated compared with the number of people with lower risk, even if the decrease in relative risk is the same in both groups.

To illustrate this point, suppose that intervention reduces mortality by 25% in primary and secondary prevention, then a high-risk patient with coronary heart disease (CHD) has a chance to die from cardiovascular disease (CVD) over the next 10 years equal to 20%, while in a patient with a low risk, the chance of dying for the same period is 1%.

To save one life among high-risk individuals, only 20 patients need to be treated for 10 years, and 4 of them will die. Thus, reducing the relative risk by 25% will save one life (3 death instead of 4). In the case of a low risk, so that a 25% reduction in relative risk would lead to 3 deaths instead of 4, 400 people will have to be treated, of whom 4 will also die.

Thus, the total cost of one life saved is significantly lower (1/20 of the cost) among those with a high absolute risk. Costly interventions are usually cost-effective only for high-risk individuals, but with a low intervention cost, the cost-effectiveness relationship can be cost-effective even in low-risk populations.

When forecasting a risk, the “ideal” risk factor (DF) is one whose prevalence prevails in a population that can be easily and safely measured and which has a great predictive value.

The measurement should be inexpensive because cost is a major constraint on the use of imaging techniques such as electron beam tomography (CRT) or MRI. In addition, the frequency of false positives should be low to avoid unnecessary and potentially dangerous consequences. Age and gender are examples of non-modifiable risk factors (RF) that meet these criteria.

Blood pressure and smoking are examples of modifiable risk factors (RF) that are easy to identify. The results of diagnostic tests can also serve as predictors of future cardiovascular events (SSSob).

Risk factor assessment at the population level

Risk factor assessment at the population level

To conduct sound public policy, it is necessary to assess the contribution of various risk factors (RF) at the population level. The population risk depends not only on the strength of the factor-disease association and the benefits of the intervention, but also on how widespread this risk factor (RF) is in the population.

For evaluation, indicators such as the frequency of new cases, prevalence, and population attributive risk are used. The frequency of new cases is the emergence of new cases of disease or risk factors (RF) for a certain period of time; prevalence is the proportion of people with a specific disease or risk factor (RF) at a given time.

The population attributive risk shows what amount of risk is caused by a given risk factor (RF), and depends on the proportion of people with this risk factor and on the magnitude of the associated risk.

Population attributive risk also reflects the relationship between exposure to a risk factor (RF) and a disease. Many factors linearly increase risk, so a population attributable risk can be calculated relative to the ideal standard or to an individual with a low risk.

For example, the relationship between hypertension and heart disease or cerebral stroke (MI) is linear, so a decrease in blood pressure at any elevated level reduces the risk. In contrast, the shape of the risk curve for obesity is not linear, the risk increases logarithmically, i.e. Each kilogram gained is associated with a higher risk for those who are already overweight.

Population attributive risk is an important criterion in determining the resources needed for carrying out various preventive interventions and determining priorities in measures to improve public health, such as anti-smoking campaigns. However, this chapter focuses on individual risk assessment for predicting future cardiovascular events (SSSob).

The use of risk factors in clinical practice

The use of risk factors in clinical practice

Regardless of how risk factors (RF) affect the progression of atherosclerosis, they can be divided into 2 broad categories depending on their use in clinical practice:

(1) factors that are useful for risk prediction (risk predictors);
(2) factors that are targets for risk reduction interventions.

Such risk factors (RF), such as smoking and blood pressure, fall into both categories. Even if a particular factor has predictive value, it cannot be argued that modifying it will reduce the risk. If the benefit of an intervention is substantially greater than any of its risks and costs, then the intervention should be used in the appropriate population. So, how do you decide which risk factor (DF) to use as a predictor of risk and what will be the target for risk reduction?

The approaches to using a risk factor (RF) for predicting or reducing risk will be defined below. This article discusses only those risk factors (RF) that affect intermediate or long-term risk. Interventions used to quickly reduce short-term risk, such as aspirin or thrombolysis in acute myocardial infarction (AMI).

Forecasting and risk assessment. Risk prediction can be applied both to the population as a whole and to the individual. Information about the population can be obtained by studying a representative population sample in order to establish the frequency of various risk factors (RF) and plan public health objectives and resources for screening programs.

Individual risk assessment is carried out in order to identify in the population of a separate part of individuals who need a more intensive risk reduction program.

The articles on the site will briefly describe the assessment of the risk factor (RF) and the frequency of events in the general population, and further – a detailed assessment of the individual risk.

Types of evidence on risk factors

Types of evidence on risk factors

Evidence on risk factors (RF) is obtained from various sources. Studies on autopsy have shown that atherosclerosis can begin to develop even at an early age, if there are the same RF CVDs as in adults. Establishing a link between cause and effect is a major step in determining predictors, and the results of several studies are needed to select a preventive intervention. Fundamental studies of human physiology made it possible to penetrate into the mechanisms of atherogenesis and helped to establish the biological probability of a potential intervention in order to change these effects.

Observational studies involving people (cohort, prospective, case-control) are extremely useful in determining the attributive risk of a particular factor. Randomized trials can help confirm a causal relationship and are necessary for choosing interventions to reduce risk.

Each of these strategies has strengths and weaknesses. Descriptive studies (for example, the description of a single observation, a series of observations, cross-sectional, cross-cultural studies, the study of population temporal trends) have considerable value because of the ability to generate hypotheses. However, their design does not adequately control potential factors that may obscure obvious associations. Observational studies (eg, cohort, prospective, case-control) can better control potential inaccuracies.

Observational studies are particularly important in determining the attributable risk of a particular factor, when this factor has a great effect, as in the case of smoking and lung cancer. However, when small or moderate effects are studied in observational studies, the number of uncontrollable distorting factors can be as great as the probable risk itself.

In such cases, randomized studies are needed to confirm causality. When the causal relationship between RF and the disease is confirmed, appropriate intervention should be selected and applied. Even if the causal relationship is beyond doubt, research will help quantify the effect of the intervention. When the question arises about the choice between risk and benefit of intervention, randomized studies are needed to determine its net clinical effect.

This provision is important because the degree of associated risk is not necessarily related to the magnitude of the benefits obtained as a result of the intervention. This lack of correlation may be due to the inability of a specific intervention to achieve the desired effect, or the magnitude of the change may not lead to a corresponding change in risk. An example is the difference between the risk of an increase in blood pressure pa 1 mm Hg. st. and less than expected benefit for CHD while reducing blood pressure by the same amount. Similarly, elevated Gmc is considered to be FR KBS, and folic acid reduces Gmc levels, but randomized studies have shown that lowering Gmc levels with folic acid does not reduce the risk of KBS.

Meta-analysis allows a better assessment of the risk associated with a specific risk factor (RF), or the benefit of an intervention. For example, an assessment of the benefits of aspirin in secondary prophylaxis was obtained as a result of a large meta-analysis of data from 300 clinical studies, which demonstrated that in patients with CVD, aspirin reduces the risk of major SSSob by 25%.

After obtaining acceptable assessments of the benefits and risks for a specific risk factor (RF), a cost-effectiveness analysis can help develop guidance for an intervention. To compare interventions, a single currency is used, calculating QALY or a year of life adjusted for disability (disability-adjusted life-year, DALY). The estimates obtained from this analysis depend on the assumptions made in this analysis. Due to the fact that preventive measures are long-lasting (lasting for decades), the consequences of the initial assumptions regarding these measures may be more important than with short-term interventions. However, the cost-effectiveness indicators of interventions for CVD prevention are important because the prevalence of CHD and the cost of treating it are high.

The cost-effectiveness indicator is calculated as the ratio of the net cost to the increase in life expectancy. Interventions with a cost-effectiveness ratio <$ 40,000 for QALY are comparable to other permanent interventions, such as control of hypertension and hemodialysis. Interventions with a cost-effectiveness indicator of <$ 20 thousand for QALY are welcome, while with an indicator of> $ 40 thousand for QALY are usually perceived by insurers as intervention above an acceptable level. The economic costs of ineffective primary prevention measures for persons with modifiable DFs> 2 in the United States annually amount to $ 13.2 billion.

Cholesterol recommendations and control

Cholesterol recommendations and control

All patients with cardiovascular diseases (CVD) should be screened to determine the level of cholesterol in serum. Some controversy remains regarding screening for primary prevention. The NCEP recommends routine screening for all individuals> 20 years old, ACP (American College of Physicians) – only men 35–65 years old and women 45–65 years old, and USPSTF – screening all men aged> 35 years old and women aged 45 years old. Screening for CVD patients should include a complete fasting lipid profile, including total cholesterol, cholesterol, and HD. For patients without CVDs, the need for screening for HDL cholesterol is questionable: the NCEP recommends such screening, but the ACP does not.

Due to the fact that cholesterol cholesterol levels and the ratio of cholesterol to cholesterol cholesterol are very strong predictors of risk and help in identifying individuals with elevated levels of LDL cholesterol, despite moderate levels of cholesterol, it seems appropriate to determine cholesterol cholesterol simultaneously with cholesterol. .

To reduce the prevalence of HLP in the United States, the NCEP in 1988 released the first report on the treatment of HCS in adults. The latter was published in 2002, in 2004 some components were updated. According to the latest NCEP guidelines, the number of adults in the United States who need to modify lipid levels through lifestyle changes has grown from 52 million to 65 million, and those who need medication from 13 million to 36 million. The goals of the intervention are determined based on the individual risk of coronary heart disease. (KBS).

The updated ATP III guideline recommends different therapeutic goals depending on the patient’s overall risk calculated on the Framingham scale, taking into account other risk markers (elevated levels of TG, CRP and family history). Patients with an existing ASC (or its equivalent – DM or PAD) are at the highest risk of a cardiovascular event (SSSob), therefore their target level of ANS cholesterol is the lowest – <100 mg / dL or even lower – <70 mg / dl for those who have recently had ACS or have KBS and diabetes or high or poorly controlled RF.

In 2006, the ACC / ANA updated their secondary prevention guidelines on lipid control, repeating the recommendations made by the NCEP and strengthening some of them. As with the NCEP guideline, a target LDL-C level of <70 mg / dL was added as optional. However, ACC / ANA expanded the choice of target LDL cholesterol levels <70 mg / dl for all patients with CHD, and not just those who have a very high risk; However, this position is not supported by all researchers. In addition, patients with a TG level of 200-499 mg / dL should have a non-HDL cholesterol content <130 mg / dL, and further decrease to <100 mg / dL is considered appropriate.

According to the NCEP primary prevention guidelines, patients with a moderately high risk of CHD (RF> 2, total 10-year risk 10-20%) should receive appropriate therapy to achieve LDL <130 mg / dL (optimally <100 mg / dL) . These indicators are also a goal for patients with moderate risk (RF> 2, 10-year risk <10%). For patients with a lower risk, the target LDL level should be <160 mg / dL. In addition to this, according to the recommendations of the NCEP on lifestyle changes, the diet should include 25-35% of calories due to fat, while the proportion of saturated fatty acids should be <7% and cholesterol <200 mg / day.

It is difficult for patients to understand the calculation of calories in percentages, so it is recommended to convert them to grams of fat, protein and other components of the diet. Professional nutrition counseling can also be helpful. If using dietary therapy fails to reach the target level of LDL cholesterol, it is necessary to begin drug therapy. In all cases, it should be an addition to diet therapy and increase of FA.

The guidelines of the European Society Cardiology also include gradations of target levels. Although they are identical for all patients (cholesterol <190 mg / dl, or 5 mmol / l; LDL cholesterol <115 mg / dl, or 3 mmol / l), the duration and intensity of drug therapy are different. In primary prevention, if the 10-year absolute risk of CHD or a risk calculated for the age of 60 years> 5%, modification of the lifestyle and analysis of lipid levels after 3 months are recommended. If after this time, cholesterol or LDL cholesterol is still above the target level, then you can begin drug therapy.

For asymptomatic high-risk patients who have cholesterol and LDL cholesterol are close to target levels (5 and 3 mmol / l, respectively), target levels should be <4.5 mmol / l (175 mg / dl) for cholesterol and <2, 5 mmol / l (100 mg / dl) for LDL cholesterol. The same target levels are set for persons with KBS and / or SD.

In secondary prophylaxis in patients with high LDL cholesterol and low HDL cholesterol or high TG, aggressive treatment is necessary, perhaps even combined. For individuals with established disease, low levels of HDL cholesterol and normal LDL cholesterol, pharmacological intervention may be considered based on the results of the VA-HIT study.

Criteria for a risk factor for coronary heart disease (CHD)

Criteria for a risk factor for coronary heart disease (CHD)

Primary and secondary prevention of coronary heart disease (CHD) is indisputable for public health. Given the prevalence of this disease, preventing even a small number of cardiovascular events (SSSob) will save thousands of lives, avoid countless suffering, and save billions of dollars from the money spent on health care.

In addition, measures that can prevent coronary heart disease (CHD) can reduce the risk of other manifestations of atherosclerosis – stroke, peripheral arterial disease (PAD), and also affect hypertension, diabetes, cognitive function, cancer, depression and other chronic conditions . Due to the fact that cardiovascular diseases (CVD) have become “the number one killer” in the world, the use of large-scale preventive strategies should become the main objective of health care in developed and developing countries.

The constant accumulation of knowledge about the pathogenesis of atherosclerosis and the understanding of the relationship between lifestyle, biochemical and genetic factors and heart disease have contributed to a significant decrease in age-corrected cardiovascular mortality. The first step to prevention is the recognition of these factors as predictors of a likely atherosclerotic event. Based on risk factors (RF), scales were developed for assessing the individual risk of cardiovascular events (SSSob).

However, the disease prevention process should continue after assessing the likelihood of future events and consists in identifying an intervention that will reduce the risk. Once the studies have correlated the benefits of interventions with their risk and cost, appropriate guidelines can be developed for health care organizers.

Guidelines have been developed for the prevention of individual risk factors (RF), which ensured successful screening and modification of several major risk factors (RF): smoking, dyslipidemia (DLP), and arterial hypertension (AH). However, the implementation and integration of these guidelines remains a difficult task. The large volume and complexity of the presentation of materials in these manuals make it difficult to use them. The lack of time for doctors to act according to the recommendations is an additional barrier: only cardiovascular preventive measures recommended by the USPSTF (U.S. Preventive Services Task Force) will take the clinician at least 1.5 hours a day. The lack of appropriate remuneration also limits the use of certain preventive interventions.

The articles on the site used a new approach to the determination of risk factors (RF) in order to simplify the prevention of cardiovascular diseases (CVD). First, various types of DF and methods of using information about them in clinical practice will be discussed. It then proposes a simple approach to using RF as predictors of risk. Then follows a description of a specific sequence of preventive interventions, which are divided into three categories.

After that, this article will describe potentially modifiable risk factors (RF) and interventions, provide information on their prevalence, associated risk, benefits and costs of treatment, as well as recommendations for each RF and multifactor intervention strategies.

When cardiovascular diseases (CVD) became the dominant chronic diseases in economically developed countries, this phenomenon was regarded as a natural consequence of the aging population. In most cases, CVDs are mainly diseases of anthropogenic origin, i.e. largely dependent on a person’s lifestyle. Over the past 50 years, great progress has been made in identifying many CVDs due to lifestyle and biochemical and genetic factors, as well as in disseminating this information among the population.