Prevalence and clinical correlates of microalbuminuria in stage I hypertension.

The aim of this study was to examine the association between albumin excretion rate (AER) and office and ambulatory blood pressure (BP) and other recognized cardiovascular risk factors in 779 (569 men) 18 to 45 year-old subjects with stage I essential hypertension (mean age = 33±9 years) enrolled in the HARVEST trial. Subjects underwent office and 24-h BP measurement, AER determination by RIA, blood chemistry and echocardiography (n=510). For statistics AER was log transformed. Average AER was 11.3 ± 25 mg/24h. AER was similar in men and women (10.8±24 vs 12.7±29 mg/24h) and was unrelated to age and body mass index. 85.2% of the patients showed AER < 15 mg/24h, 8.5% between 16 and 30 mg/24h and 6.3% > 30 mg/24h. Office BP was not significantly different in the 3 groups, while systolic 24h BP was 129.7±10, 135.6±9 and 135.5±13 mmHg respectively (p < 0.001 for the <15mg/24h group vs. the two others). Office and 24-h diastolic BP was similar in the 3 groups. Left ventricular mass (LVM) was related to 24h BP for both systolic (r=0.23; p < 0.001) and diastolic BP (r=0.12; p<0.01). However, LVM was not correlated with AER. AER was unrelated to smoking, alcohol and coffee intake and to physical activity habits. These results show that: 1) The prevalence of microalbuminuria (AER>30 mg/24h) is low in stage I hypertension. 2) Subjects with borderline AER values (16–30 mg/24h) have 24-h systolic BP levels as high as those of the microalbuminuric patients, suggesting that in hypertension AER is clinically relevant even when > 15mg/24h. 3) Both AER and LVM correlated with 24hr BP but were unrelated to each other, indicating that renal and cardiac damage are not developed in a parallel fashion in the initial phase of hypertension. 4) Life-style factors do not influence AER.