Objectives: To determine the prevalence of microalbuminuria in a sample of non-diabetic hypertensive patients and to correlate the presence of microalbuminuria with the patients' different clinical profiles.
Design: A descriptive, observational, cross-sectional and non-interventional enquiry based on strict respect for the standard general practitioner's medical practice and the physician-patient relationship.
Setting: Portuguese general practitioners (GPs) who had participated in a preliminary opinion survey on evaluation of renal function in hypertensive patients.
Population: Non-diabetic uncontrolled and controlled hypertensive patients.
Method: Data were collected via written questionnaires completed by physicians at inclusion. Standard biochemical and microalbuminuria tests were performed by the laboratory chosen by each physician following the laboratory's usual practice. A Micral-Test"* to detect microalbuminuria was also performed on a spot morning urine collection.
Results: Between May and October 2003, 531 general practitioners recruited 1582 non-diabetic hypertensive patients (58% female) with a mean age of 60.4 +/- 11.3 years; 11% of them were physically active and 10% were smokers. Almost all the patients (>95%) were under antihypertensive medication; 44% were also taking statins and 19% aspirin. Of the 1582 subjects, 57% (n=906) and 41% (n=652) had uncontrolled and controlled hypertension respectively, and 34% (n=539) had markers of renal function damage such as proteinuria, hematuria, microalbuminuria or albuminuria. Data for the Micral-Test were obtained in 98% of the patients and 29% (n=458) had a positive test. The mean albuminuria level was 12.34 +/- 37.88 mg/l. Seventy-six per cent of the patients (n=1196) had a normal urine test. Microalbuminuria was significantly more frequent in patients with uncontrolled (29%) than in controlled (20%) hypertension (p < 0.01), with left ventricular hypertrophy (LVH) (33%) than without (24%) (p < 0.01), with ventricular arrhythmias (35%) than without (25%) (p < 0.05) and with cerebral hemorrhage or transient ischemic attack (41%) than without (25%) (p < 0.001).
Conclusion: This study confirmed that microalbuminuria is a powerful discriminator of high cardiovascular risk, and is associated with higher BP values and higher prevalence of LVH, ventricular arrhythmias and cerebrovascular disease in non-diabetic hypertensive patients.