Abstract P192: Temporal Trends of Differential Control Rate of Systolic and Diastolic Blood Pressure Among Korean Adults With Hypertension: The Korean National Health and Nutrition Examination Survey, 2007-2015
Authors: Cho So Mi J , Kim Hyeon Chang 
Published: March 2019

Background:
Data from the Korean National Health and Nutrition Examination Survey (KNHANES) indicate that among individuals with hypertension, 62.5% (10,204 of 16,327) are treated and the control rates differed significantly by sociodemographic factors. Such discrepancy is owed to different risk factors and biological mechanisms associated with elevated systolic and diastolic blood pressures. Therefore, we investigated temporal trends of differential blood pressure control rate by sex and age in Korean population.

Methods:
We identified 7,774 men and 8,553 women with hypertension from the 2007-2015 KNHANES, a cross-sectional and nationally representative survey of Korean civilian population. Three separate types of control rates were separately calculated for systolic (SBP-only), diastolic blood pressure (DBP-only) and systolic and diastolic blood pressures (S&DBP) among subjects with and treated for hypertension. To clarify, SBP-only control rate indicates subjects with controlled SBP yet elevated DBP and vice versa for DBP-only control rate. Control rates were compared across time by sex and age groups. Then, we used multivariate logistic regression to delineate factors associated with each type of control rate.

Results:
In total, SBP-only, DBP-only, and S&DBP control rates were 18.0%, 23.7% and 41.6% among subjects with hypertension (2,939, 3,869 and 6,792 of 16,327), and 5.6%, 19.2% and 62.5% (571, 1,959 and 6,378 of 10,204) among those treated for hypertension, respectively. Over time, decrease in SBP-only control rate was compensated by subsequent improvements in combined control rate and accompanied by increase in DBP-only control rate in both sexes.

Men aged 30-39 years with hypertension had the highest SBP-only control rate, 69.5% (472 of 679) which decreased by the older age groups. Inversely, DBP-only control rate was the highest among 70+ years group, 36.6% (701 of 1,917) and declined by younger groups. Men treated for hypertension showed similar results.
Less age-gradient results were shown in women. SBP-only control rate among women with hypertension was the highest in 30-39 years group, 59.3% (109 of 184) and decreased by older groups. However, among women treated for hypertension, there was no negative linear trend by age group. Similarly, unlike its male counterpart, DBP-only control rate showed no visible trend by age group among women with hypertension, but only among those treated for hypertension: the highest in 70+ years group, 29.0% (749 of 2,579) and declining by younger age group.
Results from multivariate logistic regression adjusted for sociodemographic and lifestyle factors were in agreement with trends observed above.

Conclusions:
Separate examination of SBP and DBP control rates demonstrated different sex- and age-differential trends, which would’ve been overlooked in and can also explain temporal changes of combined blood pressure control rate.