Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: data from the European Lacidipine Study on Atherosclerosis

OBJECTIVES: Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue. METHODS: Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 +/- 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA). RESULTS: CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14-0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63-0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units. CONCLUSIONS: The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.