Medical Research Council trial of treatment of hypertension in older adults: principal results. MRC Working Party.
OBJECTIVE
To establish whether treatment with diuretic or beta blocker in hypertensive older adults reduces risk of stroke, coronary heart disease, and death.


METHODS
Randomised, placebo controlled, single blind trial.


METHODS
226 general practices in the MRC general practice research framework.


METHODS
4396 patients aged 65-74 randomised to receive diuretic, beta blocker, or placebo. Patients had mean systolic pressures of 160-209 mm Hg and mean diastolic pressures less than 115 mm Hg during an eight week run in and were not taking antihypertensive treatment.


METHODS
Patients were randomised to atenolol 50 mg daily; hydrochlorothiazide 25 mg or 50 mg plus amiloride 2.5 mg or 5 mg daily; or placebo. The regimens were adjusted to achieve specified target pressures. Mean follow up was 5.8 years.


METHODS
Strokes, coronary events, and deaths from all causes.


RESULTS
Both treatments reduced blood pressure below the level in the placebo group. Compared with the placebo group, actively treated subjects (diuretic and beta blocker groups combined) had a 25% (95% confidence interval 3% to 42%) reduction in stroke (p = 0.04), 19% (-2% to 36%) reduction in coronary events (p = 0.08), and 17% (2% to 29%) reduction in all cardiovascular events (p = 0.03). After adjusting for baseline characteristics the diuretic group had significantly reduced risks of stroke (31% (3% to 51%) p = 0.04), coronary events (44% (21% to 60%), p = 0.0009), and all cardiovascular events (35% (17% to 49%), p = 0.0005) compared with the placebo group. The beta blocker group showed no significant reductions in these end points. The reduction in strokes was mainly in non-smokers taking the diuretic.


CONCLUSIONS
Hydrochlorothiazide and amiloride reduce the risk of stroke, coronary events, and all cardiovascular events in older hypertensive adults.
D000368:Aged; D000584:Amiloride / Q000627:therapeutic use; D001262:Atenolol / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002561:Cerebrovascular Disorders / Q000517:prevention & control*; D003327:Coronary Disease / Q000517:prevention & control*; D004232:Diuretics / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D012737:Sex Factors; D016037:Single-Blind Method
D004232:Diuretics; D006852:Hydrochlorothiazide; D001262:Atenolol; D000584:Amiloride