Gerald W. Smetana, MD


November 11, 2003


In assessing ambulatory blood pressure, do you treat patients who are nondippers even if the rest of their readings average out in the normal range?

Response from Gerald W. Smetana, MD

"White-coat hypertension" accounts for 20% to 30% of all patients with a diagnosis of hypertension based on office readings. Controversy remains regarding the optimal use of casual or 24-hour ambulatory blood pressure measurements for patients with suspected white-coat hypertension.

Blood pressure follows a predictable circadian cycle. It is lowest during sleep and rest and increases in the early morning and during physical activity. Recent studies have focused less on the notion of dippers (appropriate reduction of blood pressure during sleep) or nondippers (< 10% reduction in mean systolic blood pressure during sleep) and have instead used mean ambulatory blood pressure as a measure of the burden of risk due to hypertension.

Clement and colleagues[1] recently reported the prognostic value of ambulatory blood pressure monitoring among patients with treated hypertension. All patients in the study already had a diagnosis of hypertension based on at least 2 office blood pressure measurements and were taking antihypertensive medication. Even after office blood pressure measurement was adjusted for, ambulatory blood pressure readings predicted cardiovascular events. The relative risks for overall 24-hour mean, daytime, and nighttime systolic blood pressure were similar (1.34, 1.30, and 1.27, respectively). Other studies have shown that for patients with elevated office readings and normal ambulatory blood pressure measurements, short-term cardiovascular morbidity is no different from that of normotensive controls.

A patient who is a nondipper but has normal mean ambulatory blood pressure may be in a "prehypertensive" state. However, this patient would have no excess cardiovascular morbidity in the near term. I would recommend not treating this patient but would continue to follow office blood pressure measurements on a regular basis (eg, every 6 months). If repeated office readings exceed 140/90 mmHg (or 130/80 mmHg if target organ disease or diabetes is present), one can make the diagnosis of hypertension.

Whether all such patients should have a 24-hour ambulatory measurement before initiating therapy remains a source of controversy. The JNC-7 report bases recommendation for treatment on the office measurement of blood pressure. At least 1 recent editorial[2] suggested ambulatory measurements for all such patients before establishing a diagnosis of hypertension, but this is not the current standard of practice. In my practice, I do not routinely obtain ambulatory blood pressure measurements after a diagnosis of office hypertension unless clinical factors suggest a likelihood of white-coat hypertension.