The Syst-Eur study investigated whether active antihypertensive treatment could reduce cardiovascular complications in elderly patients with isolated systolic hypertension. Patients (> or = 60 years) were randomly assigned to active treatment (n = 2398), i.e. nitrendipine, with the possible addition of enalapril and hydrochlorothiazide, or matching placebos (n= 2297). In the intention-to-treat analysis, the between-group difference in blood pressure amounted to 10.1/4.5 mm Hg (P < 0.001). Active treatment reduced the total incidence of stroke (primary endpoint) by 42% (P = 0.003), of all cardiac endpoints by 26% (P = 0.03), and of all cardiovascular endpoints combined by 31% (P < 0.001). Cardiovascular mortality was slightly lower on active treatment (-27%; P = 0.07), but all-cause mortality was not influenced (-14%; P = 0.22). For total (P = 0.009) and cardiovascular mortality (P = 0.09), the benefit of antihypertensive treatment weakened with advancing age and for total mortality it decreased with higher systolic blood pressure at entry (P = 0.05). The benefits of active treatment were not independently related to gender or to the presence of cardiovascular complications at entry. Further analyses also suggested benefit in patients who were taking nitrendipine as the sole therapy. The per-protocol analysis largely confirmed the intention-to-treat results. It can be concluded that stepwise antihypertensive drug treatment, starting with the dihydropyridine calcium channel blocker nitrendipine, improves prognosis in elderly patients with isolated systolic hypertension.