Proteinuria as a prognostic factor during long term hypertensive care.

Within hypertensive populations, the risk of future cardiovascular complications and of death varies substantially according to the risk factor profile of the hypertensive subject. In primary hypertension, significant renal insufficiency is rarely observed, whereas proteinuria can be observed at various frequencies according to the method of analysis and severity of hypertension. The incidence of clinically apparent proteinuria varies between 4 and 16% in different hypertensive patient series. One prospective observational, epidemiological study has clearly shown that proteinuria is an important, independent predictor of both mortality and cardiovascular morbidity in an untreated population. Two large studies of hypertensive populations treated for 4 and 10 years, respectively, have shown that clinically apparent proteinuria remains as an independent predictor of death and cardiovascular morbidity in treated patients. A third long term study suggests that 'microalbuminuria' (i.e. subclinical urinary albumin excretion), if present at start of therapy, also has an important prognostic meaning during long term follow-up. However, it is not yet known whether a reduction and normalisation of the urinary excretion of albumin during long term treatment will also be associated with an improved prognosis.