Stanley S. Franklin

Masked hypertension, which is present when in-office normotension translates to out-of-office hypertension, is present in a surprisingly high percentage of untreated persons and an even higher percentage of patients after beginning antihypertensive medication. Not only are persons with prehypertension more likely to have masked hypertension than those with optimal blood pressure (BP), but also they frequently develop target organ damage prior to transitioning to sustained hypertension. Furthermore, the frequency of masked hypertension is high in individuals of African inheritance and in the presence of increased cardiovascular risk factors and disease states, such as diabetes and chronic renal failure. Nocturnal hypertension and non-dipping may be early markers of masked hypertension. Twenty-four hour ambulatory BP monitoring (ABPM), which can detect nighttime and 24 h elevated BP, remains the gold standard for diagnosing masked hypertension. Almost one-third of treated patients with masked hypertension remain as ‘masked uncontrolled hypertension’, and it becomes important, therefore, to use ABPM (and supplemental home BP monitoring) for the effective diagnosis and control of hypertension.

To the Editor: In reference to a recent paper “Is Pulse Pressure an Independent Risk Factor for Incident Stroke, Reasons for Geographic and Racial Differences in Stroke” by Glasser et al. in the American Journal of Hypertension,¹ we wish to call your attention to past publications from the Framingham Heart Study that would help to further clarify the value of pulse pressure (PP) in diagnosing cardiovascular disease (CVD) events in general, and incident stroke in particular. Importantly, unlike Framingham, which examined Caucasians almost exclusively, the REGARDS trial recruited both African Americans and Caucasians in the United States Stroke Belt; however, the REGARDS trial investigators concluded that their findings were independent of racial differences.

Whether low diastolic blood pressure (DBP) is a risk factor for recurrent cardiovascular disease (CVD) events in persons with isolated systolic hypertension is controversial. We studied 791 individuals (mean age 75 years, 47% female, mean follow-up time: 8±6 years) with DBP P P P P =0.71). Individually, coronary heart disease, heart failure, and stroke recurrent events were more likely with DBP P P <0.001). Persons with isolated systolic hypertension and prior CVD events have increased risk for recurrent CVD events in the presence of DBP <70 mm Hg versus DBP 70 to 89 mm Hg, whether treated or untreated, supporting wide pulse pressure as an important risk modifier for the adverse effect of low DBP.

Masked hypertension, defined as discordant in-office normotension versus out-of-office hypertension, is present in approximately 10 % to 40 % of patients not receiving antihypertensive treatment. Not only are persons with prehypertension more likely to have masked hypertension, but they also frequently develop target organ damage before transitioning to established sustained hypertension. Moreover, the percentage of persons with masked hypertension increases in the presence of cardiovascular disease, diabetes, or chronic renal failure. The gold standard for diagnosing masked hypertension is the 24-hour ambulatory BP monitor (ABPM), but home BP monitoring (HBPM) has also been a useful alternative procedure. Importantly, initiating antihypertensive treatment exclusively with the use of in-office BP monitoring may result in almost one-third of patients remaining with high-risk masked uncontrolled hypertension, which underscores the importance of HBPM and ABPM as supplements to in-office BP monitoring for the effective treatment of hypertension.