24-Hour Blood Pressure Control – A Predictor for Clinical Outcomes

Abstract

Although many studies have addressed the relevance of assessing blood pressure (BP) control over a 24-hour period, it is still an area of dispute among clinicians. There is no clear agreement as to which 24-hour parameters are most important and no standardized definitions. Different types of 24-hour measurement have different implications for outcomes and, differ in their impact on the health economics of hypertension. For example, several groups have reported a connection between the systolic BP surge on rising and the incidence of cardiovascular complications in hypertensives. As BP surge on rising occurs toward the end of the dosing period, the use of an antihypertensive with extended duration of action and proven forgiveness to missed dose is more likely to attenuate the adverse outcomes associated with an early morning BP surge. Studies in this area provide quantitative estimates of the relationship between suboptimal 24-hour BP control and morbidity and mortality outcomes. Growing evidence demonstrates that there are improved outcomes in those patients whose BP values are lowered throughout a 24-hour period. However, 24-hour control is even more difficult to achieve than clinic BP control, and not all antihypertensive drugs are equally capable of reducing BP over the full 24-hour period. Some drugs claim beneficial effects on certain aspects of 24-hour control but may not control other aspects adequately; plus not all drugs have the same effects on target organ damage (over and above effects due to BP control). Whilst 24-hour measurements are not needed for routine clinical practice, choosing an antihypertensive that is proven to provide complete 24-hour coverage is likely to translate into improved outcomes. Mathematical modeling can be a useful tool in linking various measures of 24-hour BP control to longer-term outcomes and when evaluating antihypertensive strategies for reimbursement purposes. However, it is important to develop standardized and agreed modeling approaches that look at effects over the whole 24-hour period, including when doses are missed.