A MULTICENTER STUDY USING CASUAL READINGS, SELF-RECORDINGS, AND AMBULATORY BLOOD-PRESSURE MONITORING TO ASSESS ISRADIPINE EFFECTS

The antihypertensive efficacy of isradipine has been widely studied. I n most studies, however, blood pressure values were assessed by casual readings (CR) only. Furthermore, whether or not such blood pressure r eadings are sufficient proof of efficacy is still under discussion. Th us, a multicenter study was devised wherein blood pressures were recor ded by CR, self-recordings, and noninvasive ambulatory monitoring (ABM ). A total of 595 patients with mild-to-moderate hypertension were tre ated for 6 months starting with 1.25 mg of isradipine twice daily. If, after 4 weeks of treatment, CR-determined diastolic blood pressure (D BP) was still >90 mm Hg, this dosage was doubled (n = 327) and, at wee k 8, pindolol at 5 mg or spirapril at 3 mg daily was added if necessar y for blood pressure control. On the basis of CR, the results confirme d 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 n ormalization rate (DBP less than or equal to 90 mm Hg) for all patient s treated was 78.2%. However, SR-determined blood pressure reduction w as 20.0/13.0 mm Hg, with a normalization rate of 42%, whereas ABM-dete rmined 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. Studies t o assess the efficacy of drugs that are based solely on CR and without a placebo control group, therefore, should be avoided.