PHWR Public Health Weekly Report

Hypertension (HTN), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure (BP) in the arteries is persistently elevated. The prevalence of HTN in Korean adults is about 30.5%. Among patients with hypertension, 10-20% are reported to have resistant hypertension. Resistant hypertension is defined as BP that is controlled with the use of more than three medicines, one of which should be a diuretic.
Previous studies state that differential diagnosis and treatment of resistant hypertension are necessary because patients with resistant hypertension have a higher risk of cardiovascular disease than patients with well-controlled hypertension. However, applying these finding to the Korean context is challenging since there are few comparable studies on resistant hypertension in Korea. Therefore, to address this lack of research, the aim of this study was to exam the current status of resistant hypertension in Korea. This study recruited and enrolled 420 patients with resistant hypertension who were over 20 years of age from 12 tertiary hospitals in Korea. Past medical history and information on antihypertensive medications were investigated, and blood and urine tests were performed. In addition, office blood pressure (BP), out-of-office BP (ambulatory BP [24-hr BP, daytime BP, and nighttime BP] and home BP) were measured. The ratio of the control group and the non-control group was analyzed according to the target blood pressure of each BP measurement (office BP <140/90 mmHg; daytime BP <135/85 mmHg; home BP <135/85 mmHg). The mean age of the 420 resistant hypertensive patients enrolled up to the second year was 60.8±13.3 years. Of these, the number of male patients was 239 (56.9%) and the accompanying rate of metabolic disease was high. There were 206 patients (49.0%) who had controlled office BP below the target BP of 140/90 mmHg. However, the number of patients with masked uncontrolled hypertension, defined as those who did not reach the target BP of out-of-office BP (either daytime mean BP or home BP [daytime BP ≥135/85 mmHg or home BP ≥135/85 mmHg]), was 136 (66.1%).
This study revealed that even in patients with resistant hypertension whose office BP is well- controlled, there are frequent cases in which out-of-office BP does not reach the target BP. Therefore, it is necessary to continuously monitor and evaluate whether resistant hypertension, both office and out-of-office BP, is well controlled through frequent measurements of out-of-office BP.

Key words Resistant hypertension, Office blood pressure, Out-of-office blood pressure, Cardiovascular disease

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