Disproportional decrease in office blood pressure compared with 24-hour ambulatory blood pressure with antihypertensive treatment: dependency on pretreatment blood pressure levels.

The long-term relationship between 24-hour ambulatory blood pressure (ABP) and office BP in patients on therapy is not well documented. From a registry we included all patients in whom antihypertensive therapy needed to be uptitrated. Drug treatment included the direct renin inhibitor aliskiren or an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or drugs not blocking the renin-angiotensin system, alone or on top of an existing drug regimen. In all patients, office BP and 24-hour ABP were obtained at baseline and after 1 year with validated devices. In the study population of 2722 patients, there was a good correlation between the change in office BP and 24-hour ABP (systolic: r=0.39; P<0.001; diastolic: r=0.34; P<0.001). However, the numeric decrease in office BP did not correspond to the decrease in ABP in a 1:1 fashion, for example, a decrease of 10, 20, and 30 mm Hg corresponded to a decrease of ≈7.2, 10.5, and 13.9 mm Hg in systolic ABP, respectively. The disproportionally greater decrease in systolic office BP compared with ABP was dependent on the level of the pretreatment BP, which was consistently higher for office BP than ABP. The white coat effect (difference between office BP and ABP) was on average 10/5 mm Hg lower 1 year after intensifying treatment and the magnitude of that was also dependent on pretreatment BP. There was a disproportionally greater decrease in systolic office BP than in ABP, which for both office BP and ABP seemed to depend on the pretreatment BP level.