Microalbuminuria: do we need a new threshold?

• Published in: Journal of human hypertension Vol. 23; no. 2; pp. 146 - 149
• Main Authors: Zamora, C R, Cubeddu, L X
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.02.2009; Nature Publishing Group
• Subjects: Albuminuria; Albuminuria - complications; Albuminuria - diagnosis; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - diagnosis; Cardiovascular Diseases - etiology; Cardiovascular Diseases - prevention & control; Cardiovascular system; Care and treatment; Complications and side effects; Coronary artery disease; Diabetes mellitus; Diagnosis; Epidemiology; Health Administration; Heart diseases; Humans; Hypertension; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Kidney Diseases - diagnosis; Kidney Diseases - etiology; Kidney Diseases - prevention & control; Lipids; Medical sciences; Medicine; Medicine & Public Health; Population studies; Public Health; Renal function; Reproducibility of Results; Risk Factors; Type 2 diabetes; viewpoint; United States; albuminuria; microalbuminuria; cardiovascular risk; Hypertension; Urinary system disease; Risk factor; Albumin; Cardiovascular disease; Microalbuminuria; Proteinuria
• DOI: 10.1038/jhh.2008.105
• ISSN: 0950-9240

Microalbuminuria (30–300 mg of albumin/24 h) is a well-known independent risk factor for kidney and cardiovascular disease and of mortality in diabetic, hypertensive and in the general population. However, recent studies indicate that increased risk is observed at levels of albuminuria much lower than those currently employed to define microalbuminuria. Such low levels were shown to predict heart disease and death, independent of age, sex, renal function, diabetes, hypertension and lipids, in subjects with cardiovascular disease, hypertension and in the general population; as well as to predict progression to hypertension. Correction of obesity and metabolic derangements lowered levels of albuminuria below 30 mg/24 h to levels not associated with increased risk (5–7 mg/24 h). Despite the lack of outcome studies, there is substantial evidence to indicate that the threshold for defining microalbuminuria (that is, albuminuria associated with increased risk) should be lowered by nearly three to four-fold from the currently defined threshold. It would be advisable that clinical scores and future guidelines would consider including microalbuminuria at the lower rates as an independent risk factor, and as an indication for implementing early intervention. Unfortunately, and despite the abundance of evidence, albuminuria measurements are still underutilized in clinical practice.