Baseline risk and outcome benefit from intensive blood pressure targeting. A systematic review

Background Randomized clinical trials (RCTs) comparing different blood pressure (BP) targets support more stringent systolic BP targets than previously recommended. We investigated the impact of baseline risk on the outcome benefit from intensive BP targeting. Methods We examined RCTs testing a tight systolic BP target (<120 mmHg) separately from trials testing a less tight (<125–140 mmHg) intensive target. Cardiovascular death and all-cause death were the primary outcomes of interest. We also examined stroke, heart failure and myocardial infarction. Results We included 11 trials, with a total of 63,090 patients. The more intensive systolic BP target was <120 mmHg in five trials and less intensive in six trials. Cardiovascular death was reduced in the <120 mmHg arm compared to the control arm (risk difference (RD) -4.61, 95 % CI -6.84 to -2.39; p < 0.0001), but not in the <125–140 mmHg arm compared to the control arm (RD -0.92, 95 % CI -2.62 to 0.78; p = 0.29). All-cause death was reduced in the <120 mmHg arm compared to the control arm (RD -5.23, 95 % CI -8.82 to -1.64; p = 0.0043), but not in the <125–140 mmHg arm compared to the control arm (RD 0.24, 95 % CI -3.16 to 3.56; p = 0.89). Examining the 11 trials as a whole, a relationship emerged between the level of risk for all-cause mortality and cardiovascular mortality in the control group and the magnitude of benefit in the group randomized to more intensive BP control. Conclusion A systolic BP target <120 mmHg consistently reduces all-cause and cardiovascular mortality. The higher the baseline risk, the greater the benefit of a more intensive BP target.