Lowering Blood Pressure to Prevent the Occurrence of Serious Cardiovascular Diseases
Cardiovascular disease is regarded as the world’s leading cause of death, causing over 17.9 million deaths each year. From WHO source that about 1/3 of the total deaths in the world.
Blood pressure can be asymptomatic for a long period until damage to vital organs occurs, so it is called the "invisible killer".
If blood pressure is not effectively controlled, the risk of cardiovascular diseases such as stroke, aneurysm, heart failure, heart attack and kidney damage will increase.
There is a close causal relationship between blood pressure and the risk of cardiovascular disease and death. Previous studies have found that blood pressure has a continuous, independent, and direct correlation with the risk of stroke, coronary heart disease, and cardiovascular death.
The risk of heart and cerebral vasculature will increase exponentially for every 20mmHg increase in systolic blood pressure or 10mmHg increase in diastolic blood pressure.
The Lancet recently published a 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".
The report shows that antihypertensive treatment can prevent the occurrence of serious cardiovascular diseases. Regardless of whether the participant has a history of cardiovascular disease or the initial blood pressure level, antihypertensive therapy can effectively reduce the risk of adverse cardiovascular events in adults.
Viatom, as a storied brand, is committed to providing healthcare solutions with experience of more than 10 years, blood pressure monitoring is one of the leading divisions. We will interpret the Lancet paper in detail.
Although previous trials have confirmed that people with a history of heart disease or stroke, antihypertensive therapy can reduce the risk of cardiovascular disease, but whether people with normal or mildly high blood pressure need antihypertensive therapy remains controversial.
Early studies did not have definitive trial conclusions on whether people with blood pressure levels below 140/90 mmHg should use antihypertensive drugs to reduce the risk of cardiovascular disease. Because there were not sufficient individual samples, and national medical teams have their own opinions on treatment.
● Experimental Data Source
The project’s research team collected data from 344,706 patients (average age 65) from 48 eligible large-scale antihypertensive treatment trials to conduct 48 randomized trials to evaluate the effect.
First, the participants were divided into two groups according to whether they had a history of cardiovascular disease: 91071 women and 95907 men were without a history of cardiovascular disease; there were 51,905 women with a history of cardiovascular disease and 105,823 men. Then according to the initial systolic blood pressure of the participants, it is subdivided into seven groups（<120、120-129、130-139、140-149、150-159、160-169 and ≥170 mmHg).
Among the 157,728 participants with a history of cardiovascular disease and 186s,988 participants without cardiovascular disease, 31,239 and 14,928 participants had systolic pressure below 130 mmHg at the beginning of the project, respectively. Among the participants with cardiovascular disease, 13,772 had a stroke, 19,452 had ischemic heart disease, and 7,833 had heart failure.
A large number of individual cases provide powerful data support for in-depth and careful study of different baseline blood pressure thresholds and the antihypertensive effect of previous cardiovascular disease states.
● Incidence of major cardiovascular events in each group after a 5 mmHg reduction in systolic blood pressure
In some trials of the study, participants were divided into two groups: the intervention and the control. The group given a placebo was regarded as the control, and the group given the active drug for hypertension was regarded as the intervention.
During the subsequent annual follow-up, it was found that in the group with a history of cardiovascular disease, with every 5mmHg decrease in systolic blood pressure, the number at risk in the intervention group decreased with every 5 mmHg reduction in systolic blood pressure from 82,657 in the first year to 47,188 in the third year and to 10,003 in the fifth years. The proportion of major cardiovascular events was less than 20% in the fifth year. The control group dropped from 82,657 to 70,312 in the third year, and to 11,408 in the fifth year. The incidence of major cardiovascular events was less than 20%.
In the non-cardiovascular disease group, the risk population in the control group decreased by 73.31% in the fifth year compared with the first year, and the risk population in the intervention group decreased by 72.77% compared with the first year. The incidence oSf major cardiovascular events in the control group was greater than that in the intervention group.
● Whether there is a history of cardiovascular disease does not affect the conclusion of the experiment
In the trial, it was also found that among the participants without cardiovascular disease in the initial examination, the incidence of major cardiovascular events in the control group was 31.9 per 1,000 people per year, while the intervention group is 25.9 when the diastolic blood pressure difference between the control group and the intervention group was 5mmHg. Among the participants with cardiovascular disease during the initial examination, the incidence of the control group and the intervention group were 39.7 and 36.0 respectively.
Therefore, regardless of whether the patient has a history of cardiovascular disease, it made no significant difference on antihypertensive treatment which would reduce the incidence of cardiovascular disease in the participants.
● Cardiovascular disease category does not affect experimental conclusions
In order to exclude the influence of different cardiovascular diseases on the experiment, the project developed an analysis and controlled trial of the effect of antihypertensive treatment on the primary and secondary results. According to the participants’ initial cardiovascular disease status, when the systolic blood pressure decreased by 5mmHg, the risk ratio of the stroke group was 87%, the risk ratio of the ischemic heart disease group was 92%, and the risk ratio of the heart failure group was 87%. The risk ratio of the cardiovascular death group was 95%, and the risk ratio of the all-cause death group was 98%.
Therefore, no matter what kind of cardiovascular disease the participant has, when the systolic blood pressure is reduced by 5mmHg, the risk of major cardiovascular events can be reduced.
● Reducing systolic blood pressure by 5mmHg may reduce the risk of major cardiovascular events