Background and aims: Metabolic syndrome (MetS) is associated with increased prevalence of echocardiographic LV hypertrophy (LVH), a potent predictor of cardiovascular (CV) outcome. Whether MetS increases risk of CV events independently of presence of LVH has never been investigated. It is also unclear whether LVH predicts CV risk both in the presence and absence of MetS.
Methods and results: Participants in the 2nd Strong Heart Study examination without prevalent coronary heart disease, congestive heart failure or renal insufficiency (plasma creatinine >2.5mg/dL) were studied (n=2758; 1746 women). MetS was defined by WHO criteria. Echocardiographic LV hypertrophy was defined using population-specific cut-point value for LV mass index (>47.3g/m(2.7)). After controlling for age, sex, LDL-cholesterol, smoking, plasma creatinine, diabetes, hypertension and obesity, participants with MetS had greater probability of LVH than those without MetS (OR=1.55 [1.18-2.04], p<0.002). Adjusted hazard of composite fatal and non-fatal CV events was greater when LVH was present, in participants without (HR=2.03 [1.33-3.08]) or with MetS (HR=1.64 [1.31-2.04], both p<0.0001), with similar adjusted population attributable risk (12% and 14%). After adjustment for LVH, risk of incident CV events remained 1.47-fold greater in MetS (p<0.003), an effect, however, that was not confirmed when diabetic participants were excluded.
Conclusion: LVH is a strong predictor of composite 8-year fatal and non-fatal CV events either in the presence or in the absence of MetS and accounts for a substantial portion of the high CV risk associated with MetS.