Effects of different regimens to lower blood pressure on major cardiovascular events in older and younger people: meta-analysis of randomised trials

Objective To quantify the relative risk reductions achieved with different regimens to lower blood pressure in younger and older adults. Design Meta-analyses and meta-regression analyses used to compare the effects on the primary outcome between two age groups (< 65 v >= 65 years). Evidence for an interaction between age and the effects of treatment sought by fitting age as a continuous variable and estimating overall effects across trials. Main outcome measures Primary outcome: total major cardiovascular events. Results 31 trials, with 190 606 participants, were included. The meta-analyses showed no clear difference between age groups in the effects of lowering blood pressure or any difference between the effects of the drug classes on major cardiovascular events (all P >= 0.24). Neither was there any significant interaction between age and treatment when age was fitted as a continuous variable (all P > 0.09). The meta-regressions also showed no difference in effects between the two age groups for the outcome of major cardiovascular events (< 65 v >= 65; P=0.38). Conclusions Reduction of blood pressure produces benefits in younger (< 65 years) and older (>= 65 years) adults, with no strong evidence that protection against major vascular events afforded by different drug classes varies substantially with age.