Additive Interaction of Metabolic Syndrome and Chronic Kidney Disease on Cardiac Hypertrophy, and Risk of Cardiovascular Disease in Hypertension

BACKGROUND: Recent epidemiologic analyses have demonstrated a link between the metabolic syndrome (MetS) and chronic kidney disease (CKD). We examined the association between MetS, CKD, and left ventricular hypertrophy (LVH), and prospectively investigated the predictive value of the combination of MetS and CKD for cardiovascular disease (CVD) in essential hypertension. METHODS: A total of 1,160 essential hypertensive patients (mean age 63 years, 53% male) underwent clinical evaluation, laboratory testing, and Doppler echocardiography, and were monitored for a mean follow-up of 4.8 years. RESULTS: At baseline, total subjects were divided into four groups according to the presence/absence of MetS and/or CKD, and, compared to the group without MetS and CKD (MetS-/CKD-); those with MetS and CKD (MetS+/CKD+) had a multivariate-adjusted odds ratio of 2.40 (95% confidence interval (CI) 1.66-3.48) for LVH. During the follow-up period, 172 subjects developed CVD. Multiple Cox regression analysis including LV mass index (LVMI) showed that the presence of MetS as well as that of CKD were each independent predictors of CVD (hazard ratio 1.90 for MetS, 1.82 for CKD). We then divided the total subjects into four groups, and found that, compared to the MetS-/CKD- group, multivariate-adjusted HR for the MetS+/CKD+ group was 3.58 (95% CI 2.14-5.95). CONCLUSIONS: Our findings suggest that, in essential hypertension, the combination of MetS and CKD is a strong risk for LVH as well as a strong and independent predictor of subsequent CVD. These findings highlight the clinical importance of the concomitance of MetS and CKD in essential hypertension.