Proteinuria as a predictor of risk of cardiovascular disease: a new insight

Mortality and morbidity due to cardiovascular disease is one of the fundamental health problems at present. Proteinuria is not only commonly recognized factor of progression of chronic renal diseases, but is also independent risk factor for cardiovascular complications. Lately, the value of albuminuria as a prognostic factor in the course of cardiovascular diseases has increased its significance. Not long ago, there was considered that only microalbuminuria (quantity of excreted albumins in urine above 30 to 300 mg daily) indicates on increased risk of complications of such diseases as arterial hypertension or diabetes. However, observational studies, as well as interventional studies lead us to verify that view. It turned out that in the general population the number of cardiovascular complications leading to death increases in proportion to the quantity of albumins excreted in urine. Moreover, it was found that the relationship is continuous in a wide range of albuminuria even at value below the lower limits accepted now as normal levels, i.e., 30 mg per day corresponding with urinory albumin concentration 20 mg/L. It means that not only the quantity of excreted albumins but also the presence of albumin in urine indicate a higher risk of cardiovascular death. It may be assumed therefore that the presence of albumin in urine gives the evidence of unfavorable functional state of the circulatory system followed by fatal consequences. Therefore, the presence of albuminuria ought to be considered in quality and quantity aspects.