Ambulatory blood pressure monitoring: is it mandatory for blood pressure control in treated hypertensive patients?: prospective observational study

Objective: Twenty-four hour ambulatory blood pressure (ABP) is superior to office blood pressure (BP) in predicting cardiovascular events. However, its use to optimise BP control in treated hypertensive patients is less well examined.

Design and method: In this observational study conducted in 899 general practitioners' offices, 4078 hypertensive patients with uncontrolled office BP were included. Antihypertensive therapy was intensified and after 1 year office BP and 24-hour ABP were measured to categorise patients according to the ESC/ESH 2007 guidelines.

Results: In this cohort (mean office BP 156/90 mmHg, mean ABP 146/85 mmHg), 2059 out of 4078 patients (50.5%) had controlled office BP (<140/90 mmHg) at 1 year examination. Of these apparently controlled patients (N=2059), 1339 (65.8%) had 24-hour ABP ≥ 130/80 mmHg, indicating masked hypertension (32.9% of all treated patients). In the prespecified subgroups the prevalence of masked hypertension was the following: diabetes 28.2%, CVD 29.1%, and CKD 32.1%. White coat hypertension (24h-ABP<130/80 mmHg and office BP ≥ 140/90 mmHg) was found in 12.4% (N=233) of patients with elevated office BP (6.1% of all treated patients), and in 5.7% of the diabetic subgroup, 5.6% CVD and 7.1% CKD. Discrepancies in BP categorisation between office BP and 24-hour ABP were high; all subjects 52.8%, diabetes 50.0%, CVD 49.0% and CKD 50.4%.

Conclusion: In hypertensive patients on therapy, 2 out of 3 with apparently controlled office BP had masked hypertension, suggesting a more aggressive therapy, and 1 out of 8 with elevated office BP had white coat hypertension potentially falsely forcing physicians to intensify therapy. The 3A Registry is listed under clinicaltrials.gov, NCT01454583.