Calcium antagonists are a first-line treatment for hypertension. The effectiveness of diltiazem, a non-dihydropyridine calcium antagonist, in reducing cardiovascular morbidity or mortality is unclear. We compared the effects of diltiazem with that of diuretics, β-blockers, or both on cardiovascular morbidity and mortality in hypertensive patients.

In a prospective, randomised, open, blinded endpoint study, we enrolled 10 881 patients, aged 50–74 years, at health centres in Norway and Sweden, who had diastolic blood pressure of 100 mm Hg or more. We randomly assigned patients diltiazem, or diuretics, β-blockers, or both. The combined primary endpoint was fatal and non-fatal stroke, myocardial infarction, and other cardiovascular death. Analysis was done by intention to treat.

Systolic and diastolic blood pressure were lowered effectively in the diltiazem and diuretic and β-blocker groups (reduction 20·3/18·7 vs 23·3/18·7 mm Hg; difference in systolic reduction p<0·001). A primary endpoint occurred in 403 patients in the diltiazem group and in 400 in the diuretic and β-blocker group (16·6 vs 16·2 events per 1000 patient-years; relative risk 1·00 [95% CI 0·87–1·15], p=0·97). Fatal and non-fatal stroke occurred in 159 patients in the diltiazem group and in 196 in the diuretic and β-blocker group (6·4 vs 7·9 events per 1000 patient-years; 0·80 [0·65–0·99], p=0·04) and fatal and non-fatal myocardial infarction in 183 and 157 patients (7·4 vs 6·3 events per 1000 patient-years; 1·16 [0·94–1·44], p=0·17).

Diltiazem was as effective as treatment based on diuretics, β-blockers, or both in preventing the combined primary endpoint of all stroke, myocardial infarction, and other cardiovascular death.