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
In the intervention group, when the systolic blood pressure is reduced ins the range of 0-5mmHg, the risk ratios of more than 50% of diseases such as DIABHYCAR, STOP2, COLM, etc. are concentrated between 1.0-1.2, when the systolic blood pressure is reduced in the range of 5-10mmHg, the risk ratio of 10% cardiovascular diseases such as SYSTEUR, PROGRESS, and CAMELOT is concentrated between 0.8-0.7. Therefore, the risk ratio of major cardiovascular events is directly proportional to the systolic blood pressure drop achieved at the test level.
In summary, regardless of whether the participant has a previous history of heart disease or not, a 5mmHG reduction in systolic blood pressure can reduce the risk of major cardiovascular events by about 10%; the corresponding proportions of stroke, heart failure, ischemic heart disease and cardiovascular death The risk reduction is 13%, 13%, 8% and 5% respectively from the research.
● Experimental Significance
This study fills the gap in the log-linear relationship between blood pressure and cardiovascular disease risk. Randomized trials also provide convincing evidence that antihypertensive therapy is within the systolic blood pressure range for people with known or unknown cardiovascular disease diagnoses. The beneficial effect of BP, and strongly refutes the recommendation that antihypertensive therapy is effective only when the blood pressure is higher than a certain threshold.
Besides padding the evidence vacancy, the finding of the search also has strong clinical and practical significance. At present, New Zealand has largely abandoned the use of hypertension as a pre-diagnostic standard during cardiovascular disease treatment, and in the second stage, people with high cardiovascular disease risk are eligible for antihypertensive treatment. In the UK, when the systolic blood pressure is lower than 140mmHg, antihypertensive therapy will not be listed in the treatment plan for cardiovascular disease.
Therefore, the author calls on most guidelines to revise the treatment of cardiovascular disease. Whether or not to treat patients with cardiovascular disease for blood pressure should not only depend on the previous diagnosis records or the patient's blood pressure level, on the contrary, as an effective means to prevent cardiovascular disease, antihypertensive therapy should be applied to people at high risk of heart disease and stroke, regardless of cardiovascular disease status or blood pressure.
● Experimental Limitations
However, the studys also has certain limitations. For example, the research only explored the effect of the use of drugs for antihypertensive therapy and cardiovascular disease history on the treatment effect, and did not make a thorough inquiry on the population still suffering from other complications. In addition, drug treatment may have an impact on other diseases besides cardiovascular disease, which was not elaborated in the study.
Therefore, one of the authors of the study, Zeinab Bidel of the University of Oxford, said: "Whether to use antihypertensive drugs should be considered from the risk of cardiovascular disease in patients, rather than just using blood pressure itself as a measure or treatment target. This is very important. We should provide a full range of clinical treatment guidelines, including exercise, nutrition, smoking cessation, appropriate medication, etc., so as to reduce the risk of cardiovascular disease."
● Real Case Feedback
Steven from the United States is a teacher. He is 45 years old. He has measured blood pressure at 180/120mmHg during the physical examination five years ago and was diagnosed with hypertension.
The doctor advised him to take medication, but Steven believed that although his blood pressure was relatively high, he had no uncomfortable symptoms except for occasional dizziness, so he refused the doctor's advice.
Two years ago, Steven suddenly fainted during class in the school, foaming at the mouth, and was diagnosed with a stroke after being taken to the hospital.
He could barely walk, but could only walk about tens of meters after a periodical treatment.
The doctor said that the patient's stroke is mainly caused by long-term hypertension leading to arteriosclerosis. Therefore, in the follow-up treatment, the patient is required to regularly take Central agonists, Calcium channel blockers and other types of antihypertensive drugs.
In addition to regular medication, Steven also purchased Viatom Armfit+ Wireless Upper Arm Blood Pressure Monitor + ECG to record his treatment progress. Every morning and evening he used Armfit+ to measure his blood pressure and reported the output of the blood pressure data recorded in Vihealth to his doctor every month.
After taking the medicine for one year, stroke numbness had improved. Steven could go out and walked for 2 hours a day, sleep quality was also improved, and blood pressure was lowered by 20mmHg.
Last month, Steven spoke with Viatom's sales manager about his treatment experience and said that his blood pressure has now been lowered by 30mmHg, and he has rarely experienced dizziness, chest tightness, palpitation and other symptoms. The sequelae of the stroke had also been eliminated, and he had returned to school to continue teaching.
According to the comparison between the blood pressure treatment and the incidence of cardiovascular disease released by The Lancet, it is necessary for patients with no history of cardiovascular disease to take drugs for blood pressure treatment, and it is also necessary to use a sphygmomanometer to monitor the changes in blood pressure of patients.
Especially during the early morning hours of 6-9 am when hypertension tends to strike, patients are advised to use a blood pressure monitor to take measurements before waking up to avoid the sudden onset of cardiovascular disease caused by hypertension and miss the best time for treatment.