Microalbuminuria in normotensive patients with autosomal-dominant polycystic kidney disease.

Microalbuminuria (MA) is present in hypertensive autosomal-dominant polycystic kidney disease (ADPKD) patients, but has not been reported in normotensive ADPKD patients. We examined the prevalence of MA and the effect of different determinants on urinary albumin excretion in a group of 42 normotensive ADPKD patients. Metabolic parameters, plasma renin activity and aldosterone and serum angiotensin-converting enzyme (ACE) activity were determined. A 24-h urine sample two or three times over a 6-month period was collected to evaluate MA. Each patient underwent an echocardiography to measure left ventricular mass. Eight patients (19%) showed MA (61.6 mg/day, range 37-164), whereas 34 patients (81%) were normoalbuminuric (8.8 mg/day, range 2-29). The groups were matched for all possible confounding variables, but microalbuminuric patients showed a tendency towards greater systolic blood pressure, plasma renin activity and left ventricular mass. There was no correlation between MA and age, sex, body mass index, systolic or diastolic blood pressure, plasma renin activity, serum ACE levels or left ventricular index. The present study demonstrates a high prevalence of MA in normotensive ADPKD patients. MA may be a predictor of early renal and vascular damage in these patients.