Management of High Blood Pressure in Those without Overt Cardiovascular Disease Utilising Absolute Risk Scores

Increasing blood pressure has a continuum of adverse risk for cardiovascular events. Traditionally this single measure was used to determine who to treat and how vigorously. However, estimating absolute risk rather than measurement of a single risk factor such as blood pressure is a superior method to identify who is most at risk of having an adverse cardiovascular event such as stroke or myocardial infarction, and therefore who would most likely benefit from therapeutic intervention. Cardiovascular disease (CVD) risk calculators must be used to estimate absolute risk in those without overt CVD as physician estimation is unreliable. Incorporation into usual practice and limitations of the strategy are discussed. 1. Introduction Physicians treat diseases. For this reason when increasing blood pressure was recognized as a risk factor for coronary artery disease and stroke, it was dichotomized into a disease state “hypertension” and a nondisease state “normotension” by creating an arbitrary cut point. This cut point has generally become lower over time as evidence of benefit in treating blood pressure levels lower than the contemporary accepted cut points accumulated. Recognition of other risk factors such as dyslipidemia, higher risk groups such as the aged [1, 2], and those with comorbid conditions such as diabetes [3] has led to differential treatment thresholds and target blood pressures resulting in confusing or conflicting guideline recommendations, depending on which peak body produced them. Is there a simpler way to identify those most likely to have a major adverse cardiovascular event who do not have overt disease, and therefore who needs rigorous therapeutic intervention for their blood pressure and other CVD risk factors? 2. Absolute Cardiovascular Risk Increasing blood pressure has a log-linear relationship with adverse risk for cardiovascular events [4]. Using this figure alone in clinical decision making risks overtreatment (“medicalization” where medication adverse events likely to exceed benefit, and adverse cost-effectiveness) and undertreatment (failure to act where medication benefit is likely to exceed adverse events and be cost effective). Estimating absolute risk, the risk of having an adverse cardiovascular event over a specified period of time (usually 5 or 10 years), is a superior method to measurement of blood pressure alone to identify who is most at risk of having a cardiovascular event and therefore who would most likely benefit from intervention [5, 6]. It does this because the figure derived is more holistic, incorporating