In a recent study, researchers debated the optimal cut-off for measuring blood pressure to prevent death or heart disease.
A recent study published in JAMA Internal Medicine debated the optimal cut-off for measuring blood pressure for different categories of hypertension to prevent death or heart disease. In order to understand this, Mattias Brunström and Bo Carlberg recently conducted a study using previous systematic reviews that they identified from sources such as PubMed, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effect. They searched for randomized controlled trials after November 2015.
The main criteria for including a study into their review were a large number of participants and at least 1000 patient-years of follow up. They drew up a meta-analysis from all the information covered by the wide span of data. Approximately 74 trials that represented 306,273 participants adding up to 1.2 million-person years were taken into account.
Starting systolic blood pressure was an important indicator of major cardiovascular events
The researchers found that the starting systolic blood pressure was an important indicator for evaluating the presence of major cardiovascular events if blood pressure lowering drugs were given. Systolic blood pressure is the highest pressure an individual’s heart can generate in order for blood to flow appropriately through the body. This pressure should generally be between 80 to 120 mmHg for most people. Individuals who generate a pressure lower or higher than this range are at risk for cardiovascular disease and require blood pressure medications.
Risk of death and heart disease decreased only if the systolic blood pressure was 140mmHg or higher before treatment
If the systolic blood pressure at the start of the studies was 160 mmHg or higher, then the reduction of blood pressure with the correct treatment regimen proved to greatly decrease the chances of having a cardiovascular risk. If the blood pressure baseline ranged between 140 to 159 mmHg, the association of mortality after taking the medication was similar even though the risk for cardiovascular events decreased. In individuals who had their blood pressure at less than 140 mmHg at the start of the study, blood pressure reduction through medication proved to not be as helpful in decreasing the rate of mortality and reducing major cardiovascular risk.
Overall, the researchers were successfully able to demonstrate a pattern in which the reduction of blood pressure was positively associated with the reduction of mortality and the risk of cardiovascular disease. They concluded that the risk of death and cardiovascular disease decreased only if the systolic blood pressure before treatment was 140mmHg or higher. If the systolic blood pressure was lower than 140mmHg, it had no effect on the mortality rate or risk of cardiovascular disease.
Written by Dr. Apollina Sharma, MBBS, GradDip EXMD
Reference: Brunström, Mattias, and Bo Carlberg. “Association of blood pressure lowering with mortality and cardiovascular disease across blood pressure levels: a systematic review and meta-analysis.” JAMA internal medicine 178.1 (2018): 28-36.