Metabolic syndrome and chronic kidney disease in high-risk Italian hypertensive patients: the I-DEMAND study

Background. Metabolic syndrome (MS) and chronic kidney disease (CKD) are well-known, independent predictors of increased cardiovascular risk. Both conditions are fairly prevalent in the general population. The aim of this study was to assess the relationship between MS or its individual components and CKD in an Italian population of hypertensive patients with normal or mildly to moderately impaired renal function under specialist care. Methods. A total of 2,916 patients (mean age 62 +/- 11 years) among those enrolled in the I-DEMAND study were taken into consideration for this analysis. MS was defined according to the NCEP-ATP III criteria. CKD was defined as an estimated GFR (abbreviated MDRD equation) <60 ml/min/1.73m(2) or as the presence of microalbuminuria (mean albumin-to-creatinine ratio >= 2.5 mg/mmol in men and >= 3.5 mg/mmol in women). Results. MS was present in 59% of our study patients. The prevalence of microalbuminuria, reduced GFR and CKD was 26%, 25%, and 41%, respectively. Patients with MS had higher urinary albumin excretion (p<0.0001), lower GFR (p=0.0077), and a greater prevalence of CKD (p<0.0001), even after adjusting for age and gender. Multivariate logistic regression analysis revealed that MS was significantly associated with CKD, even after adjusting for several potential confounders including its individual components (OR 1.33, 95% CI 1.03-1.71, p=0.0268). The association between MS and CKD was stronger in nondiabetic patients. Conclusions. Renal abnormalities and MS are frequently associated in hypertensive patients under specialist care. This relationship is independent of several potential confounding factors including the components of MS.