Pedro González Santos

Management of Dyslipidemia in the Metabolic Syndrome Recommendations of the Spanish HDL-Forum

In order to characterize the metabolic syndrome it becomes necessary to establish a number of diagnostic criteria. Because of its impact on cardiovascular morbidity/mortality, considerable attention has been focussed on the dyslipidemia accompanying the metabolic syndrome.The aim of this review is to highlight the fundamental aspects of the pathophysiology, diagnosis, and the treatment of the metabolic syndrome dyslipidemia with recommendations to clinicians.The clinical expression of the metabolic syndrome dyslipidemia is characterized by hypertriglyceridemia and low levels of high-density lipoprotein-cholesterol (HDL-C). In addition, metabolic syndrome dyslipidemia is associated with high levels of apolipoprotein (apo) B-100-rich particles of a particularly atherogenic phenotype (small dense low-density lipoprotein-cholesterol [LDL-C]. High levels of triglyceride-rich particles (very low-density lipoprotein) are also evident both at baseline and in overload situations (postprandial hyperlipidemia). Overall, the ‘quantitative’ dyslipidemia characterized by hypertriglyceridemia and low levels of HDL-C and the ‘qualitative’ dyslipidemia characterized by high levels of apo B-100- and triglyceride-rich particles, together with insulin resistance, constitute an atherogenic triad in patients with the metabolic syndrome.The therapeutic management of the metabolic syndrome, regardless of the control of the bodyweight, BP, hyperglycemia or overt diabetes mellitus, aims at maintaining optimum plasma lipid levels. Therapeutic goals are similar to those for high-risk situations because of the coexistence of multiple risk factors. The primary goal in treatment should be achieving an LDL-C level of <100 mg/dL (or <70 mg/dL in cases with established ischemic heart disease or risk equivalents). A further goal is increasing the HDL-C level to ≥40 mg/dL in men or 50 mg/dL in women. A non-HDL-C goal of 130 mg/dL should also be aimed at in cases of hypertriglyceridemia.Lifestyle interventions, such as maintaining an adequate diet, and a physical activity program, constitute an essential part of management. Nevertheless, when pharmacologic therapy becomes necessary, fibrates and HMG-CoA reductase inhibitors (statins) are the most effective drugs in controlling the metabolic syndrome hyperlipidemia, and are thus the drugs of first choice. Fibrates are effective in lowering triglycerides and increasing HDL-C levels, the two most frequent abnormalities associated with the metabolic syndrome, and statins are effective in lowering LDL-C levels, even though hypercholesterolemia occurs less frequently. In addition, the combination of fibrates and statins is highly effective in controlling abnormalities of the lipid profile in patients with the metabolic syndrome.

Significance of High Density Lipoprotein-Cholesterol in Cardiovascular Risk Prevention

In the approach to lipid-related risk factors for cardiovascular diseases, serum high density lipoprotein-cholesterol (HDL-C) levels bear a particular significance as this lipoprotein is considered to be an antiatherogenic factor mainly, but not only, because of its influence and impact on reverse cholesterol transport. Hence the need and requirement to consider serum HDL-C levels for both primary and secondary prevention of cardiovascular disease. A particularly important aspect is the association of the ‘low HDL syndrome’ with the metabolic syndrome.These factors force us to consider serum HDL-C level as a therapeutic target by itself, or even in association with low density lipoprotein-cholesterol (LDL-C) levels when the latter are increased. This review stresses the aspects connecting serum HDL-C levels and cardiovascular risk, and looks at the populations that should be considered amenable to therapeutic management because of low serum HDL-C levels.We review therapeutic strategies, both pharmacological and nonpharmacological. The aim of this review is to present therapeutic management recommendations for correcting the proportion of cardiovascular risk that is attributable to changes in HDL-C. Serum HDL-C levels of >40 mg/dL must be a therapeutic target in primary and secondary prevention. This goal is particularly important in patients with low serum HDL-C levels and ischemic heart disease (IHD) or its equivalents, even if the therapeutic target for serum LDL-C levels (<100 mg/ dL) has been achieved. The first choice for this clinical condition is fibric acid derivates. The same therapeutic option should be considered in patients without IHD with low serum HDL-C levels and high cardiovascular risk (>20%), hypertriglyceridemia, type 2 diabetes mellitus, or metabolic syndrome.

Combinaciones de estatinas y fibratos: implicaciones farmacocinéticas y clínicas

Resumen En la dislipemia mixta del tipo de la dislipemia aterogenica, tras alcanzar los objetivos de colesterol unido a lipoproteinas de baja densidad (cLDL) mediante tratamiento con estatinas, persiste muchas veces un riesgo residual que aconseja la adicion de un fibrato. La asociacion de estatinas y fibratos ha sido limitada por la posibilidad de interacciones farmacologicas que determinan sobre todo miopatias. Las interacciones de las estatinas con otros farmacos se producen por mecanismos farmacocineticos, fundamentalmente por alteracion de su metabolismo a nivel del sistema enzimatico CYP450, de la via de la glucuronidacion hepatica o de los transportadores responsables de su distribucion tisular. El efecto adverso mas importante de las estatinas es la miopatia, que tambien puede ser inducida por los fibratos, y que resulta mas frecuente cuando se asocian ambas medicaciones (estatinas y fibratos). Se manifiesta clinicamente por mialgias, debilidad muscular y/o elevaciones de creatinfosfocinasa, y en su forma mas grave por rabdomiolisis. Esta interaccion afecta fundamentalmente al gemfibrozilo, en base a su accion especifica sobre el sistema enzimatico citocromo P450 (CYP450), y a la interferencia con la glucuronidacion hepatica de las estatinas al utilizar las mismas isoenzimas, o con los transportadores de aniones organicos a nivel del higado. Para asociar a estatinas, debemos utilizar otros derivados del acido fibrico, preferentemente fenofibrato.With mixed dyslipidemia of the atherogenic dyslipidemia type, once the LDL-c objectives have been achieved through statin treatment, there is often a residual risk, for which the addition of a fibrate is recommended. The combination of statins and fibrates has been limited by the possibility of drug interactions, which mostly result in myopathy. Interactions between statins and other drugs are caused by pharmacokinetic mechanisms, mainly by changing the metabolism of statins in the CYP450 enzyme system, in the hepatic glucuronidation pathway or in the transporters responsible for statin distribution in tissues. The most significant adverse eff ect of statins is myopathy, which can also be induced by fibrates and is more frequent when the 2 drugs (statins and fibrates) are combined. This adverse eff ect manifests clinically as myalgia, muscle weakness, increased CK levels and, in its most severe form, rhabdomyolysis. This interaction mainly aff ects gemfibrozil due to its specific action on the CYP450 enzyme system and that interferes with the hepatic glucuronidation of statins by using the same isoenzymes and with organic anion transporters in the liver. When combining statins, we should use other fibric acid derivatives, preferably fenofibrate.