Prevalence and Trends of Isolated Systolic Hypertension among Korean Adults: the Korea National Health and Nutrition Examination Survey, 1998-2012

Background and Objectives: Systolic and diastolic blood pressure may have different effects on cardiovascular disease, but limited data is available for hypertension subtypes in the Korean population. Thus, the prevalence, and absolute number of hypertension subtypes among Korean adults was estimated. Subjects and Methods: The Korea National Health and Nutrition Examination Survey 1998-2012 was used to estimate the prevalence and absolute number of each hypertension subtype among Korean adults aged ${\geq}20years$. Hypertension was classified into four subtypes: treated hypertension (TH), isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and combined systolic and diastolic hypertension (SDH). Results: In 2012, approximately 9.5 million adults were estimated to have hypertension, which consists of 5675671 TH (60.0%), 954253 ISH (10.1%), 1649486 IDH (17.4%), and 1175506 SDH (12.4%). Between 2010 and 2012, the proportion of IDH steadily decreased with age, but ISH increased especially in older ages (${\geq}40$). Between 1998 and 2012, TH markedly increased from 1.4 million to 5.7 million while the number of untreated hypertension remained relatively constant. During the same time, the number of hypertensive elderlies increased from 507000 to 2822000 along with rapid ageing of the Korean population. Despite of significant improvement in treatment rate, there are still around 583000 elderlies with untreated hypertension (423000 ISH; 42000 IDH; 118000 SDH) as of 2012. Conclusion: Although the prevalence of hypertension has been constant over the last decades, absolute number of people with hypertension has been increasing. Along with the rapid population ageing, the number of elderly hypertension is increasing and the ISH is also becoming more prevalent.