BPLTTC – Pharmacological Blood Pressure -Lowering for Primary and Secondary Prevention of Cardiovascular Disease across Different Levels of Blood Pressure

Presented at the ESC 2020 congress by: Kazem Rahimi (Oxford, UK)

Introduction and methods

Pharmacological blood pressure (BP) lowering treatment is known to be an effective strategy to prevent CVD in individuals with a high or very high BP, typically ≥140/90 mm Hg. However, there is a long-standing controversy around the effects of pharmacological BP reduction in individuals with BP-levels below the threshold of hypertension as well as possible differences in effectiveness of therapy in persons with or without a history of CVD. This has led to conflicting guideline recommendations across countries.

The objective of the study was to evaluate the effects of BP-lowering therapy on CV outcome, stratified for CVD condition and baseline SBP-levels.

This study combined data from 48 randomized clinical trials (RCTs) in the Blood Pressure Lowering Treatment Trialist’ Collaboration (BPLTTC). Each RCT had to consist of ≥1000 persons-years of follow-up and had to compare either one drug class versus placebo, or different drug classes with one another, or a strategy of more versus less intensive treatment. In total 348,854 participants were included, and stratified according to absence (n=188,583) or presence (n=160,271) of CVD, and subsequently subdivided into seven systolic blood pressure groups, from >170 mm Hg to <120 mm Hg. The primary outcome was major CV events defined as fatal or non-fatal stroke, fatal or non-fatal MI or ischemic heart disease, or HF death or hospitalization, or CVD death. Median follow-up in the primary prevention group was 4.13 (SD: 2.1) years, in the secondary prevention group 3.7 (SD: 1.9) year. Baseline SBP was 157 (SD: 21) mmHg in the primary prevention cohort and 146 (SD: 20) mmHg in the secondary prevention cohort.

Main results

• The effects of each 5 mm Hg systolic BP reduction on major CV events were comparable in the primary and secondary prevention group (HR 0.91, 95% CI: 0.89-0.94 and HR 0.89 95% CI: 0.86-0.92, respectively, Pinteraction=1.00). In the total population, risk of major CV events was reduced by 10% with each 5 mmHg reduction. Similar results were obtained for stroke, MI or ischemic heart disease, HF, and CVD death.

• Each 5 mm Hg reduction in SBP lowered the risk of major CVD events evenly among all seven SBP groups (<120, 120-129, 130-139, 140-149. 150-159, 160-169, >170 mm Hg), regardless of the presence or absence of CVD (Pinteraction=0.12 and Pinteraction=1.00, respectively). Thus, there was no evidence to suggest that the relative risk reduction varied according to an individual’s baseline SBP.

Conclusion

In this large study from the BPLTTC, lowering of SBP by 5 mmHg resulted in a 10% reduction of major CVD. Furthermore, BP-lowering treatment resulted in a similar reduced risk among those with or without CVD and irrespective of baseline systolic BP.

The authors suggest to not simply base decisions of use of BP-lowering medication on prior diagnosis of CVD or individual’s BP level, but to consider antihypertensive medication as risk modifying treatments for prevention of CVD.

- Our reporting is based on the information provided at the ESC congress -

Watch a video by Kazem Rahimi on this study