Low-grade albuminuria and cardiovascular risk : what is the evidence?

Area of Science:

• Nephrology
• Cardiology
• Endocrinology

Background:

• Microalbuminuria (MA), defined as urinary albumin excretion (UAE) of 30-300 mg/day, is a known marker of endothelial dysfunction.
• MA is an established risk factor for cardiovascular morbidity, mortality, and end-stage renal disease, particularly in patients with diabetes mellitus or hypertension.
• Emerging evidence suggests that UAE levels below the current MA threshold ('low-grade MA') also correlate with increased risks.

Purpose of the Study:

• To highlight the clinical significance of microalbuminuria, including low-grade levels, as a predictor of cardiovascular disease and mortality.
• To explore the potential role of MA screening in the general population, analogous to blood pressure and lipid screening.
• To emphasize the modifiable nature of MA and the benefits of renin-angiotensin system inhibition.

Main Methods:

• Review of prospective observational trials examining the association between UAE levels and cardiovascular/all-cause mortality.
• Analysis of evidence supporting the role of MA in apparently healthy individuals.
• Consideration of the availability and reliability of albuminuria screening assays.

Main Results:

• UAE levels below the conventional MA threshold ('low-grade MA') are associated with increased risk of cardiovascular disease and all-cause mortality.
• This association is evident even in individuals without diabetes or hypertension.
• MA is a modifiable risk factor.

Conclusions:

• Microalbuminuria, even at low levels, serves as a critical indicator of endothelial dysfunction and increased disease risk.
• MA screening may hold significant clinical value for disease prediction in broader populations.
• Inhibition of the renin-angiotensin system effectively reduces cardiovascular events in individuals with MA.