Effect of long-term antihypertensive treatment on white-coat hypertension.

Limited evidence is available on the extent and frequency by which antihypertensive treatment lowers office blood pressure (BP) in white-coat hypertension (WCH). Data are even more scanty and discrepant on the corresponding effect on ambulatory BP (ABP). In the hypertensive patients of the European Lacidipine Study on Atherosclerosis (ELSA), office and ABP were measured before treatment and at 6-month (office BP) or 12-month (ABP) intervals during the 4-year administration of calcium channel blocker-based or β-blocker-based treatment. The two groups were pooled and data were analyzed separately in patients with both office and ABP elevation (n=1670; sustained hypertension) or WCH (n=251; office BP elevation only). In sustained hypertension, office and 24-hour mean systolic BP were both markedly reduced through the treatment period, the mean change being -20.0±12.5 and -10.1±11.0 mm Hg, respectively (P<0.0001 for both). In striking contrast, in WCH the office BP reduction was almost as marked as in sustained hypertension (-19.1±11.2 mm Hg; P<0.0001), whereas 24-hour systolic BP values showed no fall or a slight progressive significant increase, its mean change during treatment being 1.6±8.6 mm Hg (P=0.007). Lowering of office BP occurred at a lower treatment intensity in WCH than in sustained hypertension. Similar findings were obtained for diastolic BP. In WCH, antihypertensive treatment should not be expected to have a lowering effect on ABP, even when office BP undergoes a concomitant marked and persistent reduction. The consequence of this contrasting effect on the incidence of hypertension-related outcomes remains to be established.