Australian comparative outcome trial of angiotensin-converting enzyme inhibitor - and diuretic-based treatment of hypertension in the elderly (ANBP2): objectives and protocol

Abstract

1. ANBP2 is a comparative outcome trial of angiotensin-converting enzyme inhibitor- and diuretic-based treatment of hypertension in the elderly using a prospective randomized open-label design with blinding of endpoint assessments. 2. The primary objective is to determine, in hypertensive subjects 65–84 years of age, whether there is any difference in total cardiovascular events (fatal and non-fatal) over a 5 year treatment period between the two treatment regimens. 3. The study is being conducted in general practices throughout Australia and will recruit 6000 subjects over 2–3 years (3000 in each arm of the study) to provide 30000 years of patient observation. This will allow detection of a 25% difference in the primary outcome variable at the 5% level with a power of 90%. 4. Following randomization to one of the treatment arms, each subject's blood pressure (BP) is managed by the general practitioner according to his/her usual practice to achieve goal BP with guidelines for drug therapy relevant to each treatment arm. 5. Study endpoint information is gained from a review of practice records every 3 months and these data are then assessed by an Endpoint Committee blinded for treatment randomization. 6. Interim analyses of endpoint data will be conducted at the end of randomization and then annually until the final analysis after 5 years of observation in each subject.