Raised Blood Pressure is So Harmful that Reductions are Beneficial Even Without Addressing Underlying Causes
The raised blood pressure of hypertension causes harm throughout the body, raising mortality risk and accelerating the onset and progression of numerous forms of ultimately fatal age-related disease. It accelerates atherosclerosis, and raises the risk of a fatal rupture of blood vessels weakened by atherosclerotic lesions. It causes pressure damage to delicate tissues throughout the body. It leads to detrimental remodeling of heart tissue and the onset of heart failure. Thus forcing a reduction in blood pressure is quite beneficial in later life, even when it is achieved - as is presently the case - by overriding regulatory mechanisms, without addressing any of the underlying forms of cell and tissue damage that produce hypertension. Imagine how much better the outcomes could be if those forms of damage were addressed, reducing not only hypertension but many other forms of downstream harm.
Blood pressure medication can prevent heart attacks and strokes - even in people with normal blood pressure. "Greater drops in blood pressure with medication lead to greater reductions in the risk of heart attacks and strokes. This holds true regardless of the starting blood pressure level, in people who previously had a heart attack or stroke, and in people who have never had heart disease."
There has been controversy about whether pharmacological blood pressure lowering is equally beneficial in people with versus without a prior heart attack or stroke, and when blood pressure is below the threshold for hypertension (typically 140/90 mmHg). Evidence from previous studies has been inconclusive, leading to contradictory treatment recommendations around the world. This was the largest - and most detailed - study ever conducted to examine these questions. The researchers combined data on individuals who had participated in a randomised clinical trial and conducted a meta-analysis. The study included 348,854 participants from 48 trials.
Participants were divided into two groups: those with a prior diagnosis of cardiovascular disease and those without. Each group was divided into seven subgroups based on systolic blood pressure at study entry (less than 120, 120-129, 130-139, 140-149, 150-159, 160-169, 170 and above mmHg). Over an average four years of follow-up, each 5 mmHg reduction in systolic blood pressure lowered the relative risk of major cardiovascular events by about 10%. The risks for stroke, ischaemic heart disease, heart failure, and death from cardiovascular disease were reduced by 13%, 7% and 14% and 5%, respectively. Neither the presence of cardiovascular disease nor the level of blood pressure at study entry modified the effect of treatment.