Lipid therapy for cardiovascular disease with insulin resistance, diabetes, or the metabolic syndrome

Associations between metabolic dysfunction-associated fatty liver disease and atherosclerotic cardiovascular disease

Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic syndrome and remains a major global health burden. The increased prevalence of obesity and type 2 diabetes mellitus (T2DM) worldwide has contributed to the rising incidence of NAFLD. It is widely believed that atherosclerotic cardiovascular disease (ASCVD) is associated with NAFLD. In the past decade, the clinical implications of NAFLD have gone beyond liver-related morbidity and mortality, with a majority of patient deaths attributed to malignancy, coronary heart disease (CHD), and other cardiovascular (CVD) complications. To better define fatty liver disease associated with metabolic disorders, experts proposed a new term in 2020 - metabolic dysfunction associated with fatty liver disease (MAFLD). Along with this new designation, updated diagnostic criteria were introduced, resulting in some differentiation between NAFLD and MAFLD patient populations, although there is overlap. The aim of this review is to explore the relationship between MAFLD and ASCVD based on the new definitions and diagnostic criteria, while briefly discussing potential mechanisms underlying cardiovascular disease in patients with MAFLD.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Body weight, plasma insulin, and coronary events with gemfibrozil in the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT)

BACKGROUND

The Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT) showed that gemfibrozil significantly reduced major coronary events in men with known coronary heart disease (CHD). To better understand why therapy was especially effective with obesity, diabetes, and hyperinsulinemia, changes in body weight and plasma insulin were determined after 1 year of gemfibrozil or placebo therapy and related to changes in lipids and CHD events.

RESULTS

With gemfibrozil significantly more subjects lost weight (51.7% versus 38.6%, P<0.0001) and significantly fewer subjects gained weight (42.5% versus 54.0%, P<0.0001) than with placebo. Both a greater loss and smaller gain in weight with gemfibrozil were age-related and significant in subjects > or =66 years (median age), but not in younger subjects. Weight change was paralleled by changes in insulin. With gemfibrozil, CHD events were significantly reduced with weight loss (hazard ratio [HR], 0.61; 95% CI, 0.44-0.84; P=0.002) and, particularly, with diabetes or hyperinsulinemia (HR, 0.53; 95% CI, 0.34-0.83; P=0.006). In contrast, CHD events were not significantly reduced without weight loss (HR, 0.83; 95% CI, 0.62-1.12; P=0.22).

CONCLUSIONS

In VA-HIT, gemfibrozil resulted in weight loss associated with reductions in insulin. With weight loss gemfibrozil produced a significant reduction in CHD events that did not occur in the absence of weight loss.

Fibric acid derivatives in cardiovascular disease prevention: results from the large clinical trials

PURPOSE OF REVIEW

Results from five large placebo-controlled trials with second-generation fibrates have shown varying success in reducing cardiovascular events. This review focuses on a number of extended analyses from these trials that may relate to the success or failure of fibrate therapy and indicate who might likely benefit from this therapy.

RECENT FINDINGS

Results have been far from uniform and several trials have been adversely impacted by high off-trial statin use. Collective evidence suggests, however, that fibrates have optimum cardiovascular benefit in diabetes or other manifestations of insulin resistance. Much of this evidence comes from posttrial analysis in subgroups with more sharply defined clinical characteristics than in the overall trial population. Analyses also suggest that different fibrates have a different range of favorable clinical properties, that the cardiovascular benefit of fibrates may not be readily measured or mostly predicted by changes in traditional lipid measurements, and that other nonlipid properties of fibrates as peroxisome proliferator-activated receptor agents might explain some of the benefit of these drugs.

SUMMARY

Results of major clinical endpoint trials with fibrates, although not uniformly positive, provide substantial evidence for a selective therapeutic role of these drugs in cardiovascular event reduction in diabetes or insulin resistance.