Is metabolic syndrome a useless category in subjects with high cardiovascular risk? Results from a cohort study in men with erectile dysfunction

Abstract

Introduction: Although several studies have demonstrated that MetS is associated with a two-fold increase in the risk of cardiovascular (CV) diseases, this risk does not appear to be greater than the sum of risks associated with each of its individual components.

Aim: To determine the association of men with ED and individual components of MetS and their subsequent relationship to CV risk, and, more specifically whether the sum of the MetS components is greater than the individual components in predicting CV risk.

Methods: We longitudinally studied a consecutive series of 1,687 (mean age 52.9±12.8; range 17-88 years) patients attending our clinic for ED and evaluated different clinical and biochemical parameters.

Main outcome measures: Information on major adverse CV event (MACE) was obtained through the City of Florence Registry Office.

Results: One hundred thirty-nine MACE, 15 of which were fatal, occurred during a mean follow-up of 4.3±2.6 years. Subjects with MetS at baseline showed a higher incidence of MACE (hazard ratio [HR]=1.77), after adjusting for age, however, the association disappeared in an alternative Cox model, adjusting both for age and for individual MetS components (HR=1,525 [0,564-4,123]; P=0.408). The two most predictive MetS components of CV risk were low high-density lipoprotein (HDL) cholesterol and high triglycerides. Exploring possible interactions between individual components of MetS and their effect on CV risk using two alternative approaches indicates that the effect of MetS components on CV risk is additive, but not synergistic. Among subjects with hypertension, after adjusting for age, elevated glycemia, and low HDL cholesterol confer relevant additional risk, while in subjects with high triglycerides, hyperglycemia increased the risk of incident MACE.

Conclusions: With regards to CV risk, the MetS construct seems to add little or nothing to the careful assessment of its components. Thus, there is no reason to recommend the use of MetS as a diagnostic category in patients with ED.