Background: Some patients with essential hypertension manifest greater than normal urinary excretion of albumin (UAE). Authors of a few retrospective studies have suggested that there is an association between microalbuminuria and cardiovascular risk.
Objective: To evaluate whether microalbuminuria is associated with a greater than normal risk of cardiovascular and renal events.
Methods: We performed a retrospective cohort analysis of 141 hypertensive individuals followed up for approximately 7 years. Hypertensive patients were defined as having microalbuminuria if the baseline average UAE of three urine collections was in the range 30-300 mg/24 h.
Results: Fifty-four patients had microalbuminuria and 87 had normal UAE. At baseline, the two groups were similar for age, weight, blood pressure, and rate of clearance of creatinine. Serum levels of cholesterol, triglycerides, and uric acid in patients with microalbuminuria were higher than levels in those with normal UAE, whereas levels of high-density lipoprotein cholesterol in patients with microalbuminuria were lower than levels in patient with normal UAE. During follow-up, 12 cardiovascular events occurred among the 54 (21.3%) patients with microalbuminuria and only two such events among the 87 patients with normal UAE (P < 0.0002). Stepwise logistic regression analysis showed that UAE (P = 0.003), cholesterol level (P = 0.047) and diastolic blood pressure (P = 0.03) were independent predictors of the cardiovascular outcome. Rate of clearance of creatinine from patients with microalbuminuria decreased more than did that from those with normal UAE (decrease of 12.1 +/- 2.77 versus 7.1 +/- 0.88 ml/min, P < 0.03).
Conclusions: This study suggests that hypertensive individuals with microalbuminuria manifest a greater incidence of cardiovascular events and a greater decline in renal function than do patients with normal UAE.