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

Abstract

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 > or =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.

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> or =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 > or =65; P=0.38).

Conclusions: Reduction of blood pressure produces benefits in younger (<65 years) and older (> or =65 years) adults, with no strong evidence that protection against major vascular events afforded by different drug classes varies substantially with age.

Fig 1 Comparison of blood pressure lowering regimens against placebo or less intensive control. SBP/DBP difference=overall difference in mean blood pressure during follow-up between treatment groups (actively treated group versus control group), calculated by weighting difference observed in each contributing trial by number of individuals in trial. Negative blood pressure values indicate lower mean follow-up blood pressure in first listed than in second listed groups

Fig 2 Comparison of angiotensin receptor blocker based regimens with control regimens. SBP/DBP difference=overall difference in mean blood pressure during follow-up between treatment groups (angiotensin receptor blocker treated group versus control group), calculated by weighting difference observed in each contributing trial by number of individuals in trial. Negative blood pressure values indicate lower mean follow-up blood pressure in first listed than in second listed groups

Fig 3 Blood pressure lowering regimens based on different drug classes for the outcome total major cardiovascular events and age groups <65 versus ≥65. SBP/DBP difference=overall difference in mean blood pressure during follow-up between treatment groups (group assigned first listed treatment versus group assigned second listed treatment), calculated by weighting difference observed in each contributing trial by number of individuals in trial. Negative blood pressure values indicate lower mean follow-up blood pressure in first listed than in second listed groups

Fig 4 Regimens based on diuretics and β blockers versus other active agents for total major cardiovascular events according to age. SBP/DBP difference=overall difference in mean blood pressure during follow-up between group assigned first listed treatment versus group assigned diuretic or β blocker, calculated by weighting difference observed in each contributing trial by number of individuals in trial. Negative blood pressure values indicate lower mean follow-up blood pressure in first listed than in second listed groups

Fig 5 Proportionate increase in relative risk of major cardiovascular events, first listed v second listed, for every extra 10 years of age

Fig 6 Associations of reduction in blood pressure with risk reduction for total major cardiovascular events for adults aged <65 and ≥65. Area of each circle is proportional to inverse variance of log odds ratio. Fitted lines represent summary meta-regressions for total major cardiovascular events