White-coat hypertension is a familiar term to most clinicians. Patients with white-coat typically have elevated blood pressure measurements in the clinician’s office, but display normal BP measurements in their everyday environment. The prevalence of white-coat hypertension varies from 15% to 20% of patients. Conversely, there is another group of individuals whose hypertension often goes unnoticed by traditional methods of BP measurement. These patients have normal in-office BP but elevated out-of-office BP. This phenomenon is referred to as “masked hypertension” and is defined as having in-office BP < 140/90 mm Hg but daytime ambulatory or home BP ≥ 135/85 mmHg.
An article exploring the increasing prevalence of masked hypertension was recently published in The Journal of Clinical Hypertension1. In the article, the authors point to research indicating the prevalence of masked hypertension to range from 10% - 47% in people who otherwise present with a normal in-office BP. Based on the 10-year follow-up from the Ohasama study2, masked hypertension has been closely associated with an increased risk of sustained hypertension and cardiovascular events. However, masked hypertension offers very few clinical hints or indications for ease of diagnosis.
It’s clear that masked hypertension is easily overlooked, however the research shows that it must be taken seriously. For many clinicians, masked hypertension is an unfortunate blind spot in the landscape of antihypertensive therapy3. The exact number of masked hypertensive patients remains a mystery, however, tools like ambulatory blood pressure monitoring are an excellent means for providing the necessary visibility to overcome this blind spot. Do you have any ideas? We would love to hear them!
- Cohen, D. L. , & Townsend, R. R. (2010). Masked hypertension: an increasingly common but often unrecognized issue in hypertension management. The Journal of Clinical Hypertension, 12(7), 522-523.
- Ohkubo, T, Kikuya, M, Metoki, H, Asayama, K, Obara, T, Hashimoto, J, Totsune, K, Hoshi, H, Satoh, H, & Imai, Y. (2005). Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h amublatory blood pressure monitoring: 10-year follow-up from the ohasama study. Journal of the American College of Cardiology, 46(3), 508-515.
- Kario, K. (2005). Time for focus on morning hypertension: pitfall of current antihypertensive medication. American Journal of Hypertension, 18(2), 149-151.