[Long-term follow-up of cardiovascular risk markers in patients with hypertension. Rationale, design, and baseline characteristics of the i-Search Plus Registry]. / Langzeitverlauf kardiovaskulärer Risikomarker bei Patienten mit Hypertonie. Rationale, Design und Ausgangscharakteristika des i-SEARCH Plus Registers.

ABSTRACT

BACKGROUND: Cardiovascular risk markers like microalbuminuria (MAU), highly sensitive C-reactive protein (hsCRP) and brain natriuretic peptide (BNP) currently gain importance to estimate risk in trials and clinical practice. Blockade of the renin-angiotensin system (RAS) has been shown to reduce some of these risk markers in clinical trials, but validation of their time course and role in clinical practice is still pending. DESIGN: To fill this gap, the design of a nationwide registry study was chosen in which patients attending their cardiologist were observed for 12 months and the effect of blocking the RAS with the angiotensin II receptor blocker irbesartan was documented. Primary question risk for mortality and the incidence of cardiovascular events in relation to baseline values of MAU, hsCRP, and BNP. Secondary questions correlations between cardiovascular risk markers (1) amongst each other with respect to cardiovascular events, (2) with clinical findings (echocardiography, electrocardiogram), (3) with the heart rate, (4) with further metabolic parameters (blood sugar, HbA(1c), etc.), and (5) with blood pressure control. RESULTS: Until April 1, 2006, 2,149 patients were recruited in 305 centers in Germany. Patients had a mean age of 61.4 (+/- 11.3) years. Waist circumference was 103.6 (+/- 13.5) cm. 95.1% of all patients had arterial hypertension at inclusion (> or = 140/90 mmHg). The mean value for albumin/creatinine was 68.9 (+/- 307.5) mg/g (n = 2,100), for hsCRP 4.6 (+/- 8.3) mg/l (n = 2,136), and for proBNP 236.5 (+/- 557.3) pg/ml (n = 2,138). CONCLUSION: The present register will elucidate the time course and the interdependence of the cardiovascular risk markers MAU, hsCRP and proBNP as well as their prediction of cardiovascular endpoints in hypertensive individuals. In addition, the role of RAS-blocking agents will be evaluated. A valuable contribution to estimate risk and to optimize care for cardiovascular high-risk patients in clinical practice can be expected.