A new study has confirmed what we already know – lowering blood pressure reduces the risk of death, with the greatest benefit seen in those at higher risk to begin with. Does this mean that everyone should be taking antihypertensives?
It is no secret that reducing risk factors for life-threatening diseases can reduce mortality. This is at the heart of modern medical thinking and public health initiatives, and is behind the substantial fall in cardiovascular mortality in recent years.
Cardiovascular disease is still one of the major causes of death in Western countries, and its main risk factors are smoking, diabetes (often associated with obesity), high cholesterol and high blood pressure. A generation ago, each risk factor was managed in isolation, with people who were above a threshold value for cholesterol or blood pressure receiving treatment for that specific risk factor. Today, the focus is on assessing an individual’s overall risk, and applying management strategies that are most likely to reduce disease and mortality. It was seeing the failings of the previous approach and wanting to evaluate the overall risk that motivated us at Crystallise to start mortality modelling in the 1990s, and you can explore the impact of different risk factors and their modification in our free Sonata Vivo mortality model.
It is therefore no surprise that Dena Ettehad and colleagues have found that reducing blood pressure can reduce overall mortality and deaths from various cardiovascular diseases, and that the benefit is greater the more the blood pressure was reduced.
The researchers combined data from 613,815 participants in 123 clinical studies of blood pressure lowering in a high quality systematic review and meta-analysis. They found that every 10 mm Hg reduction in systolic blood pressure significantly reduced the risk of all-cause mortality by 13%, with a relative risk of 0·87 (95% confidence interval 0·84 to 0·91). This was driven by a significant reduction in major cardiovascular disease events (relative risk 0·80, 95% CI 0·77 to 0·83), coronary heart disease (0·83, 0·78 to 0·88), stroke (0·73, 0·68 to 0·77), and heart failure (0·72, 0·67 to 0·78).
Our Sonata Vivo mortality model shows this benefit graphically. The chart below shows that a 50 year old man with average values of cholesterol and body mass index, who is not diabetic and a non-smoker, would gain an extra 0.5 years in life expectancy if his systolic blood pressure falls from 130 mmHg to 120 mmHg.