Blood Pressure Lowering Medication Reduces Risk of Cardiovascular Events in Adults

Kazem Rahimi

A recent study found a fixed degree of pharmacological blood pressure lowering was effective in both primary and secondary prevention of major cardiovascular disease (CVD), as well as in patients with blood pressure levels not considered for treatment.

Investigators, led by Kazem Rahimi, Nuffield Department of Women’s and Reproductive Health at the University of Oxford, indicated that the risk of cardiovascular (CV) events was reduced by 10% with a 5mm Hg reduction of systolic blood pressure, regardless of previous CV events.

The team analyzed 48 randomized trials of pharmacological blood pressure lowering medication versus placebo, or other classes of blood pressure lowering medication. Data in 51 studies from 1972 – 2013 was obtained through the Blood Pressure Lowering Treatment Trialists’ Collaboration (BPLTTC).

Trials from the BPLTTC were included that collected information about baseline blood pressure measurements, primary and secondary outcomes, and the presence or absence of previous CVD at baseline.

Data was collected to investigate the stratified effect of blood-pressure lowering treatment in patients with and without reporting CVD overall (myocardial infarction, stroke) and in 7 systolic blood pressure categories (<120 – ≥170 mm Hg).

Rahimi and team’s primary outcome was a major CV event, defined in study as compositive, including a composite of fatal and non-fatal stroke, fatal or non-fatal myocardial infarction or ischemic heart disease, or heart failure causing death or requiring admission to hospital.

Individual trials were separated into 2 groups: intervention and comparator. Placebo-controlled trials considered the placebo as comparator and active drug as the intervention. Trials with 2 or more active groups considered the group with the greater blood pressure reduction level as intervention and the treatment group as the comparator.

Results

Investigators used data from 344,716 randomly assigned participants from 48 trials in the meta-analysis. The 48 trials included 37 trials of participants with and without CVD at baseline, 10 trials with participants with previous CVD at baseline, and 1 trial exclusively with patients without previous CVD at baseline.

The pre-randomization mean systolic/diastolic blood pressure was 146/84 mm Hg in patients with previous CVD (n = 157,728) and 157/89 mm Hg in patients without previous CVD (n = 186,988).

At baseline, 31,239 (19.8%) of participants with previous CVD and 14,928 (8.0%) of participants without previous CVD had a systolic blood pressure of less than 130 mm Hg.

According to investigators, effects of the blood-pressure lowering treatment was proportional to the intensity of systolic blood pressure reduction.

A median 4.15 years of follow-up found 42,324 (12.3%) patients had at least 1 major CV event.

Participants without previous CVD experienced an incidence rate for developing a major CV event of 31.9 per 1000 person-years (95% CI, 31.3 – 32.5) in the comparator group. An incidence rate of 25.9 per 1000 person-years (95% CI, 25.4 – 26.4) was found in the intervention group.

Participants with previous CVD at baseline had a rate of 39.7 per 1000 person-years (95% CI, 39.0 – 40.5) and 36.0 (95% CI, 35.3 – 36.7) in the comparator and intervention groups.

Investigators found hazard ratios (HR) associated with the reduction of systolic blood pressure by 5 mm Hg were 0.91 (95% CI, 0.89 – 0.94) for those without previous CVD, and 0.89 (95% CI, 0.86 – 0.92) for those with previous CVD.

Conclusion

Investigators concluded that physicians indicating blood pressure lowering treatment should emphasize the importance of reducing CV risk, rather than blood pressure reduction alone.

“For people at risk of cardiovascular disease, pharmacological blood pressure-lowering treatment should become a cornerstone of risk prevention irrespective of cardiovascular disease status or blood pressure,” investigators wrote.

In a comment accompanying the study, Thomas Kahan of the Karolinska Institute agreed with the investigators regarding the future of cardiovascular treatment.

“These findings have important implications for clinical practice and suggest that antihypertensive treatment might be considered for any person for whom the absolute risk for a future cardiovascular event is sufficiently high,” Kahan wrote.

The study, “Pharmacological blood pressure lowering for primary and secondary prevention of cardiovascular disease across different levels of blood pressure: an individual participant-level data meta-analysis,” was published online in The Lancet.