A multicenter study using causal readings, self-recordings, and ambulatory blood pressure monitoring to assess isradipine effects. AMICUS Study Group.

The antihypertensive efficacy of isradipine has been widely studied. In most studies, however, blood pressure values were assessed by causal readings (CR) only. Furthermore, whether or not such blood pressure readings are sufficient proof of efficacy is still under discussion. Thus, a multicenter study was devised wherein blood pressure were recorded by CR, self-recordings, and noninvasive ambulatory monitoring (ABM). A total of 595 patients with mild-to-moderate hypertension were treated for 6 months starting with 1.25 mg of isradipine twice daily. If, after 4 weeks of treatment, CR-determined diastolic blood pressure (DBP) was still > 90 mm Hg, this dosage was doubled (n = 327) and, at week 8, pindolol at 5 mg or spirapril at 3 mg daily was added if necessary for blood pressure control. On the basis of CR, the results confirmed that low dosages of isradipine twice daily are safe and effective in the treatment of mild-to-moderate hypertension. The mean decrease in CR-determined blood pressure was 28.5/19.0 mm Hg at week 24, and the normalization rate (DBP < or = 90 mm Hg) for all patients treated was 78.2%. However, SR-determined blood pressure reduction was 20.0/13.0 mm Hg, with a normalization rate of 42%, whereas ABM-determined blood pressure reduction was 7.0/4.2 mm Hg. On the basis of ABM recordings, 66% of the patients had a DBP < 90 mm Hg on entry into the study and their blood pressures did not decrease with treatment. Thus, it appears that CR-determined blood pressures bias study results by including normotensives and thereby overestimating efficacy.(ABSTRACT TRUNCATED AT 250 WORDS)