Prevalence and clinical correlates of microalbuminuria in essential hypertension: the MAGIC Study. Microalbuminuria: A Genoa Investigation on Complications.

The prevalence of microalbuminuria and its relationship with several cardiovascular risk factors and target organ damage were evaluated in a cohort of 787 untreated patients with essential hypertension. Albuminuria was measured as the albumin-to-creatinine ratio in three nonconsecutive, first morning urine samples. The prevalence of microalbuminuria was 6.7%. Albuminuric patients were more likely to be men and to be characterized by higher blood pressure, body mass index, and uric acid levels and lower HDL cholesterol and HDL cholesterol-to-LDL cholesterol ratio. Piecewise linear regression analysis demonstrated that uric acid and diastolic blood pressure significantly influence albuminuria and together account for a large part of its variations. K-means cluster analysis performed on the entire cohort of patients confirmed that microalbuminuria is associated with a worse cardiovascular risk profile. Furthermore, microalbuminuria was associated with the presence of target organ damage (eg, electrocardiographic [ECG] abnormalities and retinal vascular changes). Age and the presence of microalbuminuria act as independent risk factors for the development of ECG abnormalities and retinal vascular changes. Cluster analysis allowed us to identify three subgroups of patients who differed in the presence or absence of microalbuminuria, retinopathy, and ECG abnormalities. We conclude that the prevalence of microalbuminuria in essential hypertension is lower than previously reported. Increased urinary albumin excretion is associated with a worse cardiovascular risk profile and is a concomitant indicator of early target organ damage.

Microalbuminuria: a marker of cardiovascular risk and organ damage in essential hypertension.

Microalbuminuria (Mi) is thought to reflect diffuse vascular damage and to predict cardiovascular morbidity and mortality in essential hypertension, although its pathogenesis remains to be fully elucidated. The relationship between microalbuminuria and several cardiovascular risk factors and target organ damage was evaluated in a large cohort of untreated essential hypertensive patients. Albuminuria was measured as the albumin to creatinine ratio in three non consecutive first morning urine samples. Cardiac damage was evaluated by ECG and retinal vascular changes by direct ophtalmoscopy. In a subgroup of 23 patients with Mi and in a control group of 22 normoalbuminurics, selected from the entire cohort of patients and carefully matched for age, gender, body mass index (BMI) and duration of disease, we also measured left ventricular mass index by M-B mode echocardiography, common carotid wall thickness by high resolution US-scan, and renal vascular resistances by US-doppler of interlobar arteries. K-means cluster analysis performed on the entire cohort of patients showed that microalbuminuria is associated with the presence of an unfavorable risk profile and target organ damage. Furthermore, microalbuminuric hypertensive patients have a larger left ventricular mass index, increased intima media thickness of carotid arteries and higher intrarenal vascular resistances as compared to a well matched group of normoalbuminuric patients. We conclude that in essential hypertension increased urinary albumin excretion can be useful to identify patients for whom more aggressive preventive strategies and/or additional treatment measures are advisable.

Prevalence of micro- and macroalbuminuria and their relationship with other cardiovascular risk factors in essential hypertension.

A cohort of 227 untreated essential hypertensive patients from north-western Italy was studied in order to evaluate the prevalence of micro- and macroalbuminuria and their relationship with other cardiovascular risk factors. Albuminuria was evaluated as the albumin to creatinine ratio (Alb/Cr) in three non-consecutive first morning samples. The prevalence of microalbuminuria and macroalbuminuria was 10% and 2.2%, respectively. Albuminuric patients showed higher blood pressure, serum creatinine, triglycerides and uric acid as well as a greater prevalence of retinopathy. Stepwise multiple regression analysis demonstrated that only a small part of variations in albuminuria was explained by changes in blood pressure. Duration of disease did not seem to influence microalbuminuria. The presence of hypertensive retinopathy was associated with greater albuminuria, longer duration of hypertension, and higher prevalence of major ECG changes, but not with higher blood pressure levels. Microalbuminuria, rather than a consequence of elevated blood pressure levels, seems to be a marker of a syndrome featuring, among other characteristics, essential hypertension. Furthermore, microalbuminuria must be considered as an independent cardiovascular risk factor.

Increased renal resistive index in patients with essential hypertension: a marker of target organ damage.

BACKGROUND: Increased renal resistance detected by ultrasound (US) Doppler has been reported in severe essential hypertension (EH) and recently was shown to correlate with the degree of renal impairment in hypertensive patients with chronic renal failure. However, the pathophysiological significance of this finding is still controversial. METHODS: In a group of 211 untreated patients with EH, we evaluated renal resistive index (RI) by US Doppler of interlobar arteries and early signs of target organ damage (TOD). Albuminuria was measured as the albumin to creatinine ratio (ACR) in three non-consecutive first morning urine samples. Left ventricular mass was evaluated by M-B mode echocardiography, and carotid wall thickness (IMT) by high resolution US scan. RESULTS: RI was positively correlated with age (r=0.25, P=0.003) and systolic blood pressure (SBP) (r=0.2, P=0.02) and with signs of early TOD, namely ACR (r=0.22, P=0.01) and IMT (r=0.17, P<0.05), and inversely correlated with renal volume (r=-0.22, P=0.01) and diastolic blood pressure (r=-0.23, P=0.006). Multiple linear regression analysis demonstrated that age, gender, ACR and SBP independently influence RI and together account for approximately 20% of its variations (F=8.153, P<0.0001). When clinical data were analysed according to the degree of RI, the patients in the top quartile were found to be older (P<0.05) and with higher SBP (P<0.05) as well as early signs of TOD, namely increased ACR (P<0.002) and IMT (P<0.005 by ANOVA), despite similar body mass index, uric acid, fasting blood glucose, lipid profile and duration of hypertension. Furthermore, patients with higher RI showed a significantly higher prevalence of microalbuminuria (13 vs 12 vs 3 vs 33% chi2=11.72, P=0.008) and left ventricular hypertrophy (40 vs 43 vs 32 vs 60%, chi2=9.25, P<0.05). CONCLUSIONS: Increased RI is associated with early signs of TOD in EH and could be a marker of intrarenal atherosclerosis.