Overview of the i-SEARCH global study: Cardiovascular risk factors and microalbuminuria in hypertensive individuals

Microalbuminuria (MAU) is a highly predictive, sensitive, inexpensive and easily repeatable marker of cardiovascular risk and all-cause mortality in hypertensive patients. The international, observational, practice-based study i-SEARCH (Survey for Evaluating Microalbuminuria Routinely by Cardiologists in patients with Hypertension) was designed to assess the frequency with which MAU occurred in a large outpatient population who were currently treated or newly diagnosed with hypertension and were under professional care. The primary aim of the study was to define the prevalence of MAU in hypertensive outpatients attending a cardiologist or internist (i-SEARCH A) and to compare hypertensive outpatients with or without coronary artery disease (i-SEARCH B). A secondary objective was to establish a correlation between MAU and known cardiovascular risk factors. A total of 21 050 patients from 26 countries were included in the primary analysis. Overall, this study demonstrated a very high worldwide prevalence (58.4%) of MAU in high-risk cardiovascular patients, but with a considerable variation across countries. MAU was more prevalent in patients with coronary artery disease than in those without. It was also significantly related to the presence of specific predictors, including male gender, abnormally high waist circumference, increased blood pressure levels (systolic ≥120 mmHg, diastolic ≥100 mmHg), creatinine clearance ≥50 mL/min, or clinical conditions such as diabetes mellitus, congestive heart failure, history of cerebral pathology, and peripheral arterial disease. Since the presence of MAU reflects long-term detrimental effects on the cardiovascular system, these results indicate the high, and in many cases hidden, burden of cardiovascular diseases among the hypertensive patients seen by cardiologists. This article discusses the main results of the study and the potential implications of ongoing analyses included in the core clinical study programme.