Comparison of bisoprolol with atenolol for systemic hypertension in four population groups (young, old, black and nonblack) using ambulatory blood pressure monitoring

The antihypertensive effects of drugs are partly determined by characteristics of the patients treated. A randomized, double-blind study used 24-hour ambulatory blood pressure (BP) monitoring to compare the effects of 2 β blockers, bisoprolol (10 to 20 mg; n = 107) and atenolol (50 to 100 mg; n = 96), administered once daily in 4 population groups. After a 4-week placebo period, patients with an office diastolic BP between 95 and 114 mm Hg were stratified according to race and age, and were randomly assigned to treatment with bisoprolol or atenolol for 8 weeks. BP averages measured by automated monitoring for the 24-hour periods were compared between groups. In elderly patients, the reductions in both average 24-hour systolic and diastolic BP were greater with bisoprolol than with atenolol ( 13 ± 3 13 ± 1 mm Hg [n = 23] vs 4 ± 2/6 ± 1 mm Hg [n = 30]; p < 0.01). Similarly, bisoprolol produced greater reductions in average 24-hour diastolic BP than did atenolol in nonblack patients ( 16 ± 2 12 ± 1 mm Hg [n = 85] vs 12 ± 2 9 ± 1 mm Hg [n = 83]; p = 0.02). Bisoprolol and atenolol were similar in the black ( 10 ± 5 9 ± 3 mm Hg [n = 22] and 10 ± 6 6 ± 3 mm Hg [n = 13], respectively) and young ( 15 ± 1 11 ± 1 mm Hg [n = 84] and 16 ± 2 10 ± 1 mm Hg [n = 66], respectively) groups. Thus, whereas bisoprolol had equal efficacy in older and younger age groups, atenolol was less effective in the elderly than in the young. The difference between the drugs in antihypertensive effects occurred despite similar β blockade, as measured by decreases in heart rate. This suggests that drugs within a class of antihypertensive agents can have differing efficacies in separate population groups.