Thirty one relevant RCTs were identified (n=13,110 patients). Six RCTs had trial arms that assessed candesartan, six assessed irbesartan, 13 assessed losartan (13), two assessed olmesartan, five assessed telmisartan, and 12 assessed valsartan.
Drug/dose-response relationships: There was a positive dose-response relationship for all the angiotensin II receptor blockers; all of them had a significant benefit for reducing diastolic and systolic blood pressure at low, moderate or high doses. There was a particularly large reduction in systolic blood pressure for valsartan when the dose was increased from 80 mg/day to 160 mg/day or above.
The mean reduction in systolic blood pressure for treatment with valsartan were -11.52mmHg (95% CI -14.39 to -8.70) for 80mg/day, -15.32mmHg (95% CI -17.09 to -13.63) for 160mg/day, and -15.85 (95% CI -17.60 to -14.20) for 320mg/day.
The relative reduction in diastolic blood pressure for treatment with valsartan were -8.71mmHg (95% CI -9.94 to -7.50) for 80mg/day, -11.33mmHg (95% CI -12.15 to -10.52) for 160mg/day and -11.97mmHg (95% CI -12.81 to -11.16) for 320mg/day.
Indirect drug/dose comparisons for mean change in blood pressure from baseline: A positive result indicated that valsartan was superior to the other angiotensin II receptor blocker in reducing blood pressure.
For 80mg/day valsartan, there was no significant difference in mean change for diastolic or systolic blood pressure when compared to other angiotensin II receptor blockers.
For 160mg/day valsartan there was a significant benefit for lowering diastolic blood pressure compared with 16mg/day candesartan (mean change 1.85mmHg, 95% CI 0.34 to 3.40). There was also a significant benefit with 160mg/day valsartan for lowering both diastolic blood pressure (mean change 2.06mmHg, 95% CI 0.71 to 3.45) and systolic blood pressure (mean change 3.56mmHg, 95% CI 0.77 to 6.38) compared with 150mg/day irbesartan. Similarly, a significant benefit was found when 160mg/day valsartan was compared with 100mg/day losartan for both diastolic blood pressure (mean change 1.95mmHg, 95% CI 0.81 to 3.11) and systolic blood pressure (mean change 3.31mmHg, 95% CI 0.86 to 5.79).
For 320 mg/day valsartan compared with other angiotensin II receptor blockers, the only significant differences were reductions in diastolic blood pressure (mean change from baseline 2.60mmHg, 95% CI 1.45 to 3.76) and systolic blood pressure (mean change 3.84mmHg, 95% CI 1.34 to 6.31) when compared with 100mg/day losartan.