Palatini P et al. (2006) Glomerular hyperfiltration predicts the development of microalbuminuria in stage 1 hypertension: the HARVEST. Kidney Int 70: 578–584

In people with overt hypertension, microalbuminuria is associated with an increased incidence of fatal events. Detection of microalbuminuria should, therefore, trigger early intervention. But can the onset of microalbuminuria precede that of hypertension and, if so, how can its onset be predicted? Palatini et al. sought answers to these questions by analyzing data from the Hypertension and Ambulatory Recording Venetia Study (HARVEST).

Treatment-naive subjects with borderline (stage 1) hypertension but no microalbuminuria (n = 502) were followed for an average of almost 8 years. During follow-up, albumin excretion rate increased to a significantly greater extent in subjects with excessive glomerular filtration at baseline (creatinine clearance exceeding 150 ml/min/1.73 m2) than in those without hyperfiltration (P <0.001). When adjusted for confounding factors such as age, sex, 24 h blood pressure and BMI, baseline creatinine clearance was found to be a strong independent predictor of the risk of subsequently developing microalbuminuria (P <0.001). Interestingly, blood pressure measured in the clinic was not predictive of microalbuminuria.

According to current guidelines, which recommend that antihypertensive treatment is not initiated until blood pressure exceeds 140/90 mmHg, almost 50% of subjects in this study with glomerular hyperfiltration—and therefore an increased risk of microalbuminuria—did not require treatment. On the basis of their new data, the authors assert that people screened for stage 1 hypertension with glomerular hyperfiltration should be started on angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers even if their clinic-measured blood pressure spontaneously declines to within the normal range.