Association of cardiovascular risk factors with microalbuminuria in hypertensive individuals: the i-SEARCH global study

OBJECTIVES: To define the prevalence of microalbuminuria (MAU) in hypertensive outpatients attending a cardiologist or internist (i-SEARCH A) and to compare hypertensive outpatients with or without coronary artery disease (CAD; i-SEARCH B). A secondary objective was to establish a correlation between MAU and known cardiovascular risk factors. METHODS: i-SEARCH was an international, observational study. which enrolled consecutive outpatients with hypertension. Patients with reasons for a false-positive MAU test were excluded. Main outcome measures were the prevalence of MAU as assessed using a dipstick test, hypertension co-morbidities, co-medication and presence of known cardiovascular risk factors. RESULTS: A total of 21,050 patients, from 26 countries, were included in the primary analysis. Overall prevalence of MAU was 58.4% (men > women), although there was considerable variation in prevalence across countries and continents (maximum 71% in Vietnam/Indonesia; minimum 53% in Germany/Switzerland). In multivariate analyses, predictors of MAU were identified to be male gender, high waist circumference, systolic blood pressure >or= 120 mmHg, diastolic blood pressure >or= 100 mmHg, creatinine clearance >or= 50 ml/min, and the presence of diabetes, congestive heart failure, CAD, history of cerebral pathology, peripheral arterial disease, dyspnoea or palpitations. MAU was present more often in patients with CAD than in patients without. CONCLUSIONS: MAU is extremely common in hypertensive outpatients worldwide, especially in patients with known cardiovascular risk factors. Given its importance as a strong, early and independent marker of increased cardiovascular risk in hypertension, the results of i-SEARCH mandate more rigorous MAU screening of hypertensive patients in clinical practice.