Masked Hypertension in Patients With Office BP <130/80 mm Hg
Recent guidelines propose new values for defining hypertension as office blood pressure (BP) ≥130 systolic or ≥80 mm Hg diastolic and the target for drug treatment <130/80 mm Hg. 24-hour ambulatory BP monitoring (ABPM) and home BPs are usually used to detect “white-coat” hypertension. In contrast, masked hypertension (MH) refers to normal office BP and hypertension in the home or on 24-hour ABPM. What is the prevalence of MH and of masked uncontrolled hypertension (MUCH) based on 24-hour ABPM in patients with office BP <130/<80 mm Hg (guideline suggestion), drawn from the Spanish ABPM Registry?
Values of 125/75, 130/80, and 110/65 mm Hg have been proposed for 24-hour, daytime, and nighttime periods corresponding to the office cut-off of 130/80 mm Hg. Primary care office BP was measured using standardized procedures. The registry had 115,708 patients (45,020 untreated and 70,688 treated or hypertension), of which 90% was from primary care centers and 10% from hypertension or cardiology clinics. According to the American College of Cardiology (ACC)/American Heart Association (AHA) hypertension guidelines, MH and MUCH were estimated by considering patients with mean 24-hour ABP ≥125 or ≥75 mm Hg, mean daytime BP≥130 or ≥80 mm Hg, mean nighttime BP ≥110 or ≥65 mm Hg, or any of the above. European Society of Hypertension (ESH) recommendations are 5 mm Hg higher for mean and daytime ABPM and 10 mm Hg higher for nighttime ABPM.
Mean age (standard deviation) was 59 (14) years, and 47% were women. Office BP was <130/<80 mm Hg in 7.7% and 8.4% of treated patients. Using mean daytime BP, prevalence of MH was 14% and MUCH in treated patients was 15% with the ESH criteria and 28%-30% with those proposed by the ACC/AHA guidelines. Corresponding figures by using mean 24-hour ABPM were 20% and 39%, respectively. When compared with patients with both normal office and ambulatory BP, MH or MUCH was associated with a worse cardiovascular risk profile, being older, more frequently males and smokers with higher office systolic BP, and more frequent cardiovascular disease.
The high prevalence of MH observed in untreated and treated individuals with normal BP in the office supports a wider use of ABPM in routine clinical practice.
In a recent article by the same group (Banegas et al., N Engl J Med 2018;378;1509-20), the authors reported that ABP measurements were a stronger predictor of all-cause and cardiovascular mortality than clinic BP measurements. White-coat hypertension was not benign, and most importantly, MH was associated with a greater risk of death and cardiovascular death than sustained hypertension when adjusted for the office BP. Additionally, MUCH had a >2-fold risk for all-cause and cardiovascular mortality than those with controlled treated hypertension. Of course the lower choice of target BP and lower definition of hypertension and pre-hypertension increase the potential value of 24-hour ABPM. An outcome study comparing moderate and more intense BP targets in which office BP and 24-hour ABPM are compared for predicting outcome would be complicated, but would answer many questions that are presently debated by the hypertension community.
Keywords: Blood Pressure, Blood Pressure Determination, Blood Pressure Monitoring, Ambulatory, Cardiovascular Diseases, Hypertension, Masked Hypertension, Metabolic Syndrome X, Outcome Assessment (Health Care), Prehypertension, Primary Prevention, Risk Factors, Smoking, Systole, White Coat Hypertension
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