Microalbuminuria: a neglected cardiovascular risk factor in non-diabetic individuals?

Microalbuminuria (MA), excessive albumin excretion in the urine, is defined in different ways. MA is more prevalent among patients with diabetes mellitus (DM) and/or hypertension and correlates with adverse renal and cardiovascular (CV) outcomes. Several cross-sectional and prospective studies have demonstrated a positive association between MA and CV outcomes in the general population but also specific populations such as patients with previous MI and hypertensives. The relationship between MA and hypertension is of particular importance. Increased urine albumin excretion (UAE) has been associated with left ventricular hypertrophy (LVH), subclinical markers of atherosclerosis and vascular dysfunction. Metabolic syndrome (MetS), insulin resistance (IR), inflammatory markers, lipid parameters and measures of obesity also correlate with increased UAE. Accumulating evidence suggests that a UAE value lower than the "traditionally" considered microalbuminuric threshold is associated with increased CV risk. The revision of MA definition according to the levels which confer increased CV risk in the general population should probably be considered. Further prospective studies with uniform methods of urine collection and UAE measurement as well as consistent threshold values and units may provide additional information regarding MA (or low-grade albuminuria) as a predictor of CV outcomes.