Not much need for ambulatory blood pressure monitoring

To the Editor: Neal and Irwig1 argue that more precise measurement of blood pressure using ambulatory blood pressure monitoring is unlikely to deliver the clinical and economic benefits that could be achieved by switching to a risk-based strategy, such as that advocated by the National Vascular Disease Prevention Alliance.2 Moreover, they question: do you need to “know your numbers”? However, all risk-based strategies are based on numbers for blood pressure and various lipid parameters. Furthermore, despite a wealth of evidence that numbers-based approaches reduce cardiovascular events, I am not aware of any randomised controlled trial demonstrating the superiority, or even the equivalence, of a strategy based on 5-year absolute risk for cardiovascular prevention.

Is a strategy based on 5-year absolute risk best for the individual patient? Clinicians treat lifetime risk,3 taking into account family history and, for women, the prospect of pregnancy. A low 5-year risk is not sufficient justification for withholding treatment of elevated lipids or blood pressure. Although the 44-year-old, male non-smoker without diabetes and with a systolic blood pressure of 170 mmHg may have a 5-year cardiovascular risk of 5%, clinicians will investigate and provide aggressive blood pressure treatment to reduce his lifetime risk. Treating according to the numbers will ensure that the choice of therapy offers the greatest risk reduction.

Clinicians treat individuals, not populations. Management of the individual patient with cardiovascular risk is neither exclusively numbers-based nor exclusively risk-based, but a combination of the two approaches. We should use the approach that works best for the individual patient.