Metabolic Syndrome and Early Death

Abstract

This editorial appraises an article in the current issue of Hypertension that examines the prospective relationships between features of the metabolic syndrome (MetS) and early death in a population-based cohort form Northern Italy.1 We also discuss, in light of that study’s findings, how relevant conventional definitions of the MetS are for identifying individuals at high risk of early death. The MetS describes a constellation of metabolic and cardiovascular disease risk factors. Although varying definitions of the MetS exist, all of the commonly used definitions include a measure of obesity, hyperglycemia, hypertension, and dyslipidemia.2–4 These definitions are based on “expert” opinion and not on evidence derived from prospective studies, which would be preferable. Thus, it remains uncertain whether the component features of the MetS or the thresholds at which each component is defined as present or absent are informative and optimal for predicting risk of disease or early death. It is also undetermined whether MetS represents a distinct pathophysiological entity. Notwithstanding these issues, the syndrome is extensively used in research studies, and many advocate its use in clinical practice5 to identify people at high risk of cardiovascular disease and early death. The idea that cardiovascular risk factors with a common etiology cluster in certain individuals at high risk of cardiovascular disease was first popularized by Reaven6 in the 1980s, although the origins of the MetS date back much earlier.7 Reaven’s6 emphasis was on elucidating the underlying pathophysiology of cardiovascular disease, for which he postulated that insulin resistance plays a pivotal role, and not on developing a diagnosis of MetS, which could be used in clinical practice. Superficially, at least, MetS relates strongly with cardiovascular morbidity and early death8; this is perhaps unsurprising, because so too do each of the component features of the …