The association between metabolic syndrome, microalbuminuria and impaired renal function in the general population: impact on cardiovascular disease and mortality

OBJECTIVE: Microalbuminuria and metabolic syndrome are both associated with cardiovascular disease (CVD). The aim of this study was to determine the potential association between numbers of components in the metabolic syndrome, different levels of microalbuminuria and renal function. We also aimed to determine the risk of death and CVD at different levels of microalbuminuria and renal function and numbers of components in the metabolic syndrome. DESIGN: Population-based observational follow-up study. SETTING: Epidemiological research unit (Copenhagen City Heart Study). SUBJECTS: A total of 2,696 men and women, 30-70 years of age. BASELINE MEASURES: Urinary albumin excretion (UAE), creatinine clearance and metabolic risk factors were measured in 1992-1994. MAIN OUTCOME MEASUREMENTS: The participants were followed prospectively by registers until 1999-2000 with respect to CVD, and until 2004 with respect to death. RESULTS: We found a strong association between microalbuminuria and the metabolic syndrome: 2% with none and 18% with five metabolic risk factors had microalbuminuria (P < 0.001). No association between impaired renal function defined as creatinine clearance <60 mL min(-1) and the metabolic syndrome was found. Microalbuminuria was associated with increased risk of death and CVD to a similar extend as the metabolic syndrome, irrespective of concomitant presence of metabolic syndrome (RR approximately 2; P < 0.001). Impaired renal function was not associated with increased risk of death and CVD in subjects with the metabolic syndrome. CONCLUSIONS: Microalbuminuria (UAE >5 microg min(-1)) confers increased risk of death and CVD to a similar extent as the metabolic syndrome.