Performance of two metabolic syndrome definitions in the estimation of cardiovascular disease among hypertensive patients.

The authors evaluated the significance of metabolic syndrome (MetS) diagnosis, as defined by the National Cholesterol Education Program (NCEP) and by the International Diabetes Federation (IDF), in the evaluation of cardiovascular risk in hypertensive patients. Among 638 patients, the prevalence of MetS was 54.7% when the IDF criteria were used, compared with 45.5% when the NCEP criteria were used. MetS correlated significantly with the presence of cardiovascular disease (CVD). In patients without type 2 diabetes mellitus (T2DM), only MetS diagnosed using the IDF criteria was associated with the presence of CVD. In those with T2DM, MetS was not associated with CVD, regardless of the criteria used. The diagnosis of MetS, using either set of criteria, was associated with the development of T2DM. We conclude that, in hypertensive patients without diabetes, a diagnosis of MetS according to IDF criteria, but not the NCEP criteria, is useful in identifying individuals with a higher probability of incident CVD. In patients with diabetes, a population already considered at high risk for CVD, a diagnosis of MetS, regardless of the criteria used, has no further impact on prognosis.

Is cystatin C a useful marker in the detection of diabetic kidney disease?

BACKGROUND/AIMS: To evaluate cystatin C as a marker of diabetic kidney disease in normoalbuminuric diabetic patients without chronic kidney disease (CKD). METHODS: A cross- sectional study was carried out comprising 243 hypertensive patients, 61 of them with type 2 diabetes, presenting normoalbuminuria and an estimated glomerular filtration rate (eGFR) >or=60 ml/min/1.73 m(2). Renal function assessment included determinations of serum creatinine and cystatin C levels, microalbuminuria, as well as eGFR through Cockcroft-Gault and Modification of Diet in Renal Disease equations. RESULTS: Diabetic patients presented higher cystatin C levels than nondiabetic patients (0.95 +/- 0.19 vs. 0.89 +/- 0.17 mg/l; p < 0.05). In the binary logistic regression, the presence of diabetes and metabolic syndrome was significantly associated with elevated cystatin C levels. Diabetic patients also presented a slightly greater albuminuria (6.72 +/- 4.43 vs. 5.07 +/- 3.59 microg/min; p < 0.05). CONCLUSIONS: Our results suggest that elevated cystatin C levels in diabetic patients may identify a certain degree of renal dysfunction even when albuminuria and eGFR do not mirror CKD. Longitudinal studies with direct GFR measures need to be done in order to confirm the value of cystatin C as an indicative of worse renal outcomes in the diabetic population.

Uric acid as a marker for renal dysfunction in hypertensive women on diuretic and nondiuretic therapy.

Hyperuricemia is a common finding in hypertensive patients, especially among those who are on diuretic therapy. However, its clinical relevance regarding cardiovascular and chronic kidney disease (CKD) has not clearly been established. The authors assessed whether, in a population of 385 hypertensive women categorized according to diuretic therapy, the stratification in quartiles by uric acid levels would identify a gradient of changes in renal function and in risk factors for cardiovascular disease. The following were evaluated: serum uric acid, glycemia, total and fractional cholesterol, triglycerides, apolipoprotein (Apo) B, Apo A-I, and C-reactive protein. Renal function was assessed by serum creatinine, albuminuria, and estimated glomerular filtration rate (eGFR) by the Modification of Diet in Renal Disease equation, whereas cardiovascular risk was estimated through the Framingham score. A total of 246 women were on diuretic therapy; 139 were taking other antihypertensive medications. There was a reduction in eGFR parallel to the increase in uric acid levels, regardless of diuretic use and without a concomitant increase in albuminuria. In both groups, higher uric acid levels translated into an increase in metabolic syndrome components, in markers of insulin resistance, triglyceride / high-density lipoprotein levels, and Apo B/Apo A-I ratios, as well as in Framingham scores. Hyperuricemia was associated with an increase in inflammatory markers only in patients on diuretic therapy. In a binary logistic regression, hyperuricemia (uric acid >6.0 mg/ dL) was independently associated with CKD (eGFR <60 mL/ min / 1.73 m(2)) (odds ratio, 2.63; 95% confidence interval, 1.61-4.3; P<.001). In hypertensive women, the presence of hyperuricemia indicated a substantial degree of kidney dysfunction as well as a greater cardiovascular risk profile.