Association of Normal Systolic Blood Pressure Level with Cardiovascular Disease in the Absence of Risk Factors
In 2017 guidelines from the American College of Cardiology/American Heart Association Blood Pressure Treatment, hypertension is defined with a systolic blood pressure of 130 mm Hg. The association of SBP levels and increased atherosclerotic cardiovascular disease (ASCVD) risk in healthy individuals is not known. Whelton and colleagues published a study titled “Association of Normal Systolic Blood Pressure Level with Cardiovascular Disease in the Absence of Risk Factors” in JAMA cardiology. A summary of the findings is given below:
Objective:
To study the relationship of SBP levels with ASCVD and coronary artery calcium in persons without hypertension or other traditional ASCVD risk factors in compliance with current definitions.
Method:
1457 participants from the Multi-Ethnic Study of Atherosclerosis were included in the study. These participants were free from atherosclerotic cardiovascular disease (ASCVD), were without dyslipidemia, diabetes, treatment for hyperlipidemia or diabetes, hypertension meditations, or current tobacco use, and had an SBP level between 90-129mm Hg. By adjusted hazard ratios (aHRs) and presence or absence of coronary artery calcium, the incident of ASCVD was calculated.
Findings:
Investigation suggests that with an increase in SBP levels there is an increase in coronary artery calcium and incident ASCVD. Additionally, it was reported that there is the initiation of coronary artery calcium and the risk of ASCVD with SBP levels of as low as 90 mm Hg. Along with the support of other trials, investigators suggest that rather than focusing on treatment to lower SBP levels, a life-course approach to prevent an increase in SBP levels would be effective. The study implies many reasons to maintain optimal SBP levels such as:
1) Healthy individuals with SBP level between 90-99 mm Hg have low cardiovascular disease event
2) No J point is observed with SBP level as low as 90 mm Hg
3) With higher SBP levels, there is higher traditional risk factors for ASCVD
Limitations:
Only baseline SBP levels were used in the study. Investigators added that they had focused on traditional risk factors for ASCVD and excluded behavioral factors such as diet and physical activity which are difficult to measure accurately. Authors acknowledge that for specific categorical variables such as hyperlipidemia, there are different cut points which also contributes to increasing traditional risk factors of ASCVD. But to focus on SBP levels these factors were excluded from the investigation.
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