Hypertension intervention trial in high risk patients. A comparison of the effects of nifedipine gits and hydrochlorothiazide/amiloride on cardiovascular and cerebrovascular morbidity and mortality (insight)

Objective The aim of the INSIGHT trial is to compare fatal and non-fatal cardiovascular endpoints in hypertensive patients randomised to a calcium-channel blocker (nifedipine GITS) or a thiazide diuretic (co-amilozide). Methods Six thousand six hundred patients from nine European countries (UK, France, Israel, Spain, Italy, the Netherlands, Denmark, Norway and Sweden) will be recruited, aged 55-80 and with a blood pressure ≥ or ≥160 mmHg (systolic). All patients will have at least one other major coronary risk factor. Patients will be stratified by country and risk factors and randomised to double-blind treatment with either nifedipine or diuretic. After a single dose titration, additional treatment will be atenolol or enalapril (where β-blockade is contra-indicated). Follow-up and Endpoints After achieving a target blood pressure of patients will be followed for a total of at least 3 years. Primary endpoints are myocardial infarction, stroke, heart failure, subarachnoid haemorrhage and sudden cardiac death. The study has a power of 80% at 5% significance to detect a difference between 8% event rate over three years in diuretic-treated patients and 6% in those receiving nifedipine. Conclusion INSIGHT is a large multinational outcome study of an anti-hypertensive agent newer than β-blockade or diuretic.