Microalbuminuria screening in patients with hypertension: recommendations for clinical practice

INTRODUCTION: Correlations between renal and cardiovascular (CV) pathologies in advanced kidney or heart disease are well characterised, but less clearly defined in the early stages. Microalbuminuria, in addition to being an early sign of kidney damage, is often found in patients with essential hypertension, suggesting that it may reflect early vascular abnormalities. EVIDENCE FROM LITERATURE: Studies have shown that even very low levels of microalbuminuria strongly correlate with CV risk: albumin excretion rates as low as 4.8 microg/min, well below the microalbuminuria thresholds stated in current clinical guidelines, are associated with increased risk of CV and cerebrovascular disease, independent of the presence of other risk factors. Increased microalbuminuria indicates endothelial dysfunction or developing atherosclerosis and predicts end-organ damage, major cardio or cerebrovascular events and death. CLINICAL ASPECTS: Available tests for screening microalbuminuria are sensitive, reliable and accessible; current European and US guidelines advocate annual screening in patients with diabetes and wherever possible in non-diabetic patients with hypertension. Early identification of high-risk patients through detection of microalbuminuria allows selection of aggressive treatment to slow disease progression. THERAPEUTIC IMPLICATIONS: Antihypertensive agents providing angiotensin II blockade are recommended for the treatment of hypertensive patients with microalbuminuria, regardless of diabetes and/or early or overt nephropathy. Treatment with angiotensin II receptor blockers provides effective reduction of microalbuminuria and blood pressure, and long-term prevention of CV events beyond blood pressure reduction. In addition, pharmacoeconomic studies have shown that these long-term benefits translate into a substantially reduced burden on healthcare resources.