Fifty RCTs (N=1,715) with 102 study arms were used to evaluate the outcomes: 165 patients in 13 placebo arms and 1,550 patients in 89 active treatment arms.
The number of treatment arms for each drug class were: for diuretics, 15 (N=304); for blockers, 23 (N=367); for calcium-channel blockers, 26 (N=441); and for ACE-inhibitors, 25 (N=438).
A direct comparison between two hypertensive drugs was not possible due to the small numbers of studies comparing similar drugs.
The absolute decreases in the outcome parameters were as follows.
Systolic BP: placebo, 2.9 (SD=2.8) mmHg; active 11.9 (SD=4.3) mmHg; P<0.001.
Diastolic BP: placebo, 2.6 (SD=2.7) mmHg; active, 13.6 (SD=3.8) mmHg; P<0.001. Posterior wall thickness: placebo, 0.8 (SD=4.2) mm; active, 6.4 (SD=6.0) mm; P<0.01.
Septal wall thickness: placebo, 0.3 (SD=1.0) mm; active, 7.1 (SD=6.4) mm; P<0.01.
Left ventricular mass: placebo, 5.2 (SD=5.9) g/m2; active, 9.2 (SD=7.9) g/m2; P<0.001.
Differences held true after taking account of therapy, age, pre-treatment BP and decrease in BP during treatment.
The overall decrease of left ventricular mass after 26 weeks of treatment was 9.2% (95% confidence interval, CI: 7.6, 10.8) from an average pre-treatment value of 136 g/m2. The decrease of left ventricular mass was more marked, the greater the pre-treatment value of left ventricular mass (correlation, r=0.53, P<0.001).
Similar relationships were found for changes in posterior and septal wall thickness (r=0.27, P<0.05 and r=0.24, P<0.06, respectively). The decrease in left ventricular mass index was greater with a greater reduction in systolic BP (partial r=0.26, P<0.05) adjusted for pre-treatment values, and with a greater reduction in diastolic BP (r=0.36, P<0.001). Left ventricular mass also decreased more with a greater fall in diastolic BP (partial r=0.28, P<0.05) adjusted for pre-treatment values. The determinants of reduction in left ventricular hypertrophy were the pre-treatment left ventricular mass index, the decrease in BP and the duration of treatment.
A significant difference was detected in the change in left ventricular mass index among the four antihypertensive drug classes (P<0.01) after accounting for systolic BP and age. After weighting for the number of patients, the decreases in left ventricular mass index were as follows: ACE-inhibitors, 11.8% (95% CI: 9.0, 14.5); calcium-channel blockers, 11.1% (95% CI: 7.8, 13.7); blockers, 4.5% (95% CI: 1.2, 7.3); diuretics, 8.6% (95% CI: 3.9, 11.1). ACE inhibitors and calcium-channel blockers led to a greater decrease in both left ventricular mass index (P<0.01 and P<0.05, respectively, after Bonferroni correction) and posterior wall thickness (P<0.05) than blockers. No difference was noted for changes in septal wall thickness.