[Cardiovascular risk and cardiometabolic risk: an epidemiological evaluation]

Abstract

On the basis of a critical literature review, this article deals with the concepts of global cardiovascular risk and cardiometabolic risk, pointing out their links but also their unresolved issues and discussing their usefulness in clinical practice. The global cardiovascular risk is the probability of suffering from a coronary event or stroke in a given period of time and in this sense it is an absolute risk, generally reported as percentage at 10 years. Usually risk functions are used, derived from longitudinal studies of healthy people at baseline. They consider some factors that are coherently linked with events in population analyses: among these there are some metabolic factors (total cholesterol, HDL cholesterol, fasting blood glucose), some biological factors (blood pressure) and some lifestyle factors (tobacco smoking), all modifiable beyond those non-modifiable like age and gender. The chosen factors must be independent at multivariate analysis, simple and standardized to measure, and contribute to significantly increase the risk-function predictivity. To be reliable, these risk functions must be derived from the same population where they will be later administered. For this reason the Italian Progetto CUORE, in the longitudinal study section, built a database of risk factors from longitudinal comparable studies started between the mid '80s and '90s and followed up the participants for cardiovascular mortality and morbidity to estimate the Italian global cardiovascular risk (first coronary or cerebrovascular event) for men and women. Two tools have been produced, the risk charts and a score software (see www.cuore.iss.it). The ongoing epidemics of obesity and diabetes and the fact that diabetes is associated with classical risk factors like hypertension and dyslipidemia induced the American Diabetes Association and the American Heart Association to launch a "call to action" to prevent both cardiovascular disease and diabetes. In this paper, as cardiometabolic risk factors were considered those "closely related to diabetes and cardiovascular disease: fasting/postprandial hyperglycemia, overweight/obesity, elevated systolic and diastolic blood pressure, and dyslipidemia". The association among the cardiometabolic risk factors has been known for a long time, and much of their etiology has been ascribed to insulin resistance. Also, the fact that these "metabolic" abnormalities can cluster in many individuals gave rise to the term "metabolic syndrome", a construct embraced by many organizations but questioned by other authors. From an epidemiological point of view the metabolic syndrome seems to increase modestly the cardiovascular risk, whereas in non-diabetic individuals it predicts diabetes much more efficiently. Many studies have compared the performance of the classical cardiovascular evaluation tools (the Framingham risk score, the SCORE charts, the Progetto CUORE score) and metabolic syndrome in cardiovascular disease prediction. Usually in people at high risk the presence of the metabolic syndrome does not improve the risk, whereas in people at lower risk its presence increases significantly the chances of cardiovascular disease. Many studies have shown that positive lifestyle interventions markedly reduce the rate of progression of type 2 diabetes. Also some drugs were tested for diabetes prevention, usually in people with impaired glucose tolerance. Oral diabetes drugs considered together (acarbose, metformin, flumamine, glipizide, phenformin) were less effective than lifestyle interventions, with different results among the drugs; the antiobesity drug orlistat gave similar results to lifestyle interventions. In Italy an appropriate approach to cardiovascular disease and diabetes prevention may be that of first evaluating the global cardiovascular risk using the charts or the score software of the Progetto CUORE, because high-risk subjects (> or =20%) must be treated aggressively independently of the presence of the metabolic syndrome; as a second step the metabolic syndrome may be sought, because it increases the risk; finally some attention should be paid to non-diabetic hyperglycemic individuals.