While blood pressure has been measured in clinics for over 100 years, we are now living in a time where home blood pressure monitoring is increasingly common. Blood pressure measurements done by the patient at home or automatically with ambulatory measurement machines are being evaluated as ways to better assess and treat hypertension. A recent review published in the American Journal of Kidney Diseases reviewed the literature on these newer techniques. Corresponding author Dr. Mahboob Rahman (MR), from Case Western Reserve University, discussed this topic with Dr. Joel Topf (eAJKD), eAJKD advisory board member.
eAJKD: Home blood sugar monitoring has been available for 20 years. Why do you think that only in the last few years have home blood pressure monitors really gained traction?
MR: There are probably several reasons for that. We have more data than we had 7 years ago with regard to the value of home blood pressure as a prognostic tool. Second, there’s been more data showing home blood pressure monitoring can improve blood pressure control. Finally, the technology that allows patients to communicate with doctors has blossomed. Patients can transmit their home blood pressure via e-mail or other online mediums rather than awaiting the next clinic visit. Sixty percent of people with hypertension are using home blood pressure monitors.
eAJKD: The fundamental question about target blood pressure seems to be in flux. I was surprised that the target blood pressure for home monitoring was not established; some prefer 135/85 mm Hg versus 130/80 mm Hg. What do you think should be the target blood pressure?
MR: I think that that’s a hard question to answer. Most of the data we have seen on home blood pressure readings is epidemiologic. Hence, we are looking at patients who have a blood pressure below a certain threshold or above a certain threshold, and calculating risks. These are not necessarily clinical trials. With that in mind, I think a blood pressure goal of <135/85 mm Hg is reasonable.
eAJKD: Any comments on the terminology of dippers versus non-dippers?
MR: I think that the field is moving away from a categorical definition. Instead of the dipper or the non-dipper, the data is pushing us to look at nighttime blood pressure as a continuous variable. The ratio from day to night, along with the nighttime blood pressure, is important to study.
eAJKD: Do we need to treat “white coat” hypertension?
MR: Unfortunately, the data is not conclusive. The best data suggests that if your patients have “white coat” hypertension, they are not completely normal. If you follow them long enough, they probably will develop hypertension. The blood pressure likely rises in the office due to a stress component driven by sympathetic response.
eAJKD: Masked hypertension was seen in 43% of patients; that seems like a very high percentage. Any comments?
MR: The 43% that you’re quoting is from a population of patients with chronic kidney disease in one particular study. Other studies with chronic kidney disease have shown a much lower number. If one looks at essential hypertension in patients without kidney disease, that number is about 8%
eAJKD: Any comments on the standard office blood pressure measurements in 2012?
MR: It is important not to forget about the office blood pressures. When we measure blood pressure in the office, standard protocols should be followed. All offices should routinely incorporate this protocol in their office blood pressure measurement strategy.
In summary, I think the algorithm in Figure 3 of the article will be very helpful for many practitioners when using home monitoring in their routine care of hypertensive individuals.