The drug treatment of mild hypertension in the Multiple Risk Factor Intervention Trial. A review.

The Multiple Risk Factor Intervention Trial was a long term study on the benefit of lowering risk factors for coronary heart disease mortality in middle-aged men. Study participants were randomised to either 'special intervention' or 'usual care'. Intensive intervention for special intervention men involved cholesterol lowering dietary advice, behaviour modification for cigarette smoking and a stepped care pharmacological approach to lower blood pressure. Overall, at 6 years, there was a 7.1% lower coronary heart disease mortality in special intervention compared with usual care men, a statistically non-significant difference (Confidence Interval +25 to -15%). Subgroup analysis revealed that special intervention men who were hypertensive at baseline and who had resting ECG abnormalities experienced a higher coronary heart disease mortality than the comparable usual care group. Within group Cox regression analysis, with coronary heart disease mortality as the dependent variable, revealed an interaction between diuretic use and resting ECG abnormalities in special intervention men. Additional analyses of clinics revealed a higher special intervention/usual care mortality in those clinics that used mainly hydrochlorothiazide in special intervention hypertensives. Results of the Multiple Risk Factor Intervention Trial raise important questions concerning the treatment of mild hypertension, and the clinical significance of metabolic alterations of antihypertensive drugs.