The international, prospective, randomized HOT study was aimed at determining the influence of a targeted BP reduction on cardiovascular morbidity and mortality. Patients were randomly allocated to 3 DBP targets (< 80, < 85, < 90 mmHg). In addition, the impact of a coprescription of aspirin was studied. The BP target had to be reached within 3 months, according to a well-defined strategy : felodipine 5 mg o.d. as a 1st intention drug, 1, 2 or 3 additional drugs, if necessary, on the following steps. BP measurements were made, using an oscillometric automatic device (Hestia). From April 1992 to October 1994, 18,790 patients with an age range 50-80 years, coming from 26 countries, entered the study. The data collected on the 36th month were in agreement with those obtained on the 12th and the 24th months. Baseline DBP was reduced by 21, 23 and 25 mmHg in the 90, 85 and 80 mmHg target groups, respectively. The rate of patients whose DBP reached the target, obviously increased from the 3rd to the 12th month: from 43 to 56%, 60 to 70%, 74 to 83% in the 90, 85 and 80 mmHg, target groups, respectively. From the 2nd to the 3rd year, BP control was further improved, with a slightly higher rate of controlled patients in the elderly (age > 60 y), especially in the 80 mmHg target group. From inclusion to the 3rd month, one-drug treated patients decreased, whereas 2- or 3-drug treated patients increased. Felodipine-treated patients decreased on the 36th month, but remained over 80%. From the 6th to the 36th month, additional prescription of a betablocker or an ACE-inhibitor increased from 36 to 39%, and from 23 to 28%, respectively; moreover, the side-effects rate decreased from 10.5 to 3.6%, with a special decline in ankle edema from 4 to 1%. In conclusion, the BP reduction observed on the 36th month was of the same extent as that observed in the first months. It seems obviously possible to reach a targeted DBP and to maintain it over time, along with a good acceptability of the treatment. Targeted DBP could be more easily achieved in elderly patients, possibly due to a better drug compliance.