Background and ObjectivesHeart failure (HF) is an important healthcare issue because of its high mortality, morbidity, and healthcare costs. The number of HF patients is increasing worldwide as a consequence of aging of the population. However, there are limited studies on the prevalence of HF in Korea. This study aimed to estimate the prevalence of HF, its comorbidities, and the projected population with HF in the future.Materials and MethodsThe prevalence and comorbidity estimates of HF were determined using data from the 2002-2013 National Sample Cohort based on the National Health Information Database. We calculated the projected prevalence of HF by multiplying the estimated prevalence in 2013 by the projected population counts for 2015-2040.ResultsThe prevalence of HF in Korea was estimated to be 1.53% in 2013. The prevalence of HF in Korea is expected to increase by 2-fold, from 1.60% in 2015 to 3.35% in 2040. By 2040, more than 1.7 million Koreans are expected to have HF. In terms of comorbid diseases of HF, ischemic heart disease, hypertension, and diabetes mellitus were common (45.4%, 43.6%, and 49.1% in 2013, respectively). The prevalence rates of arrhythmia, valvular disease, and cardiomyopathy in HF patients were approximately 22.6%, 5.6%, and 3.1% in 2013, respectively.ConclusionThis is the first nationwide report in Korea to demonstrate the prevalence and comorbidities of HF. These data may be used for the prevention and management of HF in Korea.

Hypertension and diabetes share common risk factors and frequently co-occur. Although high blood pressure (BP) was reported as a significant predictor of type 2 diabetes, little is known about this association in Korea. This study investigated the relationship of prehypertension and hypertension with type 2 diabetes in 7150 middle-aged Koreans, as well as the effect of BP control on diabetes development over 8 years. At 8 years, 1049 (14.7%) of the 7150 participants had newly developed diabetes, including 11.2, 16.7 and 21.5% of baseline normotensive, prehypertensive and hypertensive subjects, respectively. The overall incidence rate of diabetes was 22.3 events per 1000 person-years. Subjects with baseline prehypertension (hazard ratio (HR), 1.27; 95% confidence interval (CI), 1.09–1.48) and hypertension (HR 1.51; 95% CI, 1.29–1.76) were at higher risk of diabetes than normotensive subjects after controlling for potential confounders (P-value for trend <0.001). These associations persisted even when subjects were stratified by baseline glucose status, sex and body mass index (BMI). The risk of diabetes was significantly higher in subjects who had normal BP at baseline and progressed to prehypertention or hypertension at 8 years (HR, 1.48; 95% CI, 1.20–1.83) than those with controlled BP, but these associations were not observed in subjects with baseline prehypertension and hypertension. These findings showed that prehypertension and hypertension are significantly associated with the development of diabetes, independent of baseline glucose status, sex and BMI. Active BP control reduced incident diabetes only in normotensive individuals, suggesting the need for early BP management.

BackgroundObesity is one of the most significant risk factors for hypertension. However, there is controversy regarding which measure is the best predictor of hypertension risk. We compared body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) in subjects as predictive indicators for development of hypertension.MethodsThe data were obtained from the Korean Genome and Epidemiology Study (KoGES), a large population-based prospective cohort study. A total of 4,454 subjects (2,128 men and 2,326 women) aged 40–69 years who did not have hypertension at baseline were included in this study. Incident hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or anti-hypertensive medication use during the 4-year follow up. Receiver operating characteristic (ROC) analysis was used to compare discrimination abilities for anthropometric indices for hypertension. Hazard ratios were calculated by Cox proportional hazard model with adjustment for age, smoking status, alcohol consumption, diabetes and family history of hypertension by sexes.ResultsIn men, the area under the ROC curve (AROC) was 0.62 for WC, WHR, and WHtR and 0.58 for BMI. In women, the AROCs for BMI, WC, WHR, and WHtR were 0.57, 0.66, 0.68, and 0.68, respectively. After adjustment for risk factors, a 1 standard deviation increase in BMI, WC, WHR, WHtR were significantly related to incident hypertension, respectively (hazard ratio: 1.39, 1.50, 1.40 and 1.49 in men, 1.31, 1.44, 1.35 and 1.48 in women).ConclusionsThe central obesity indices WC, WHR, and WHtR were better than BMI for the prediction of hypertension in middle-aged Korean people. WHtR facilitates prediction of incident hypertension because of the single standard regardless of sex, ethnicity, and age group. Therefore, WHtR is recommended as a screening tool for the prediction of hypertension.

The objectives of this study were to construct a risk score for predicting incident hypertension by using the Korean Genome and Epidemiology Study (KoGES) data and to compare the performance between KoGES and the Framingham model. A total of 4747 participants were analyzed. The entire cohort was randomly assigned to derivation and validation sets at a ratio of 6:4. A hypertension risk score was developed based on the derivation cohort, using the same risk factors that were used for developing the Framingham hypertension risk score. The accuracy of KoGES and Framingham models was evaluated in terms of calibration and discrimination. The area under receiver operating characteristic (AROC) curves were 0.789 for the Framingham model and 0.791 for the KoGES model. The AROC calculated for the point-based risk score was 0.790, which is almost identical to that for the KoGES model. The Framingham model showed poor agreement (v 2 =29.73, P=.0002) and underestimated the risk of hypertension in most deciles of predicted risk. The model based on KoGES yielded results similar to the observed risk of hypertension (v 2 =4.17, P=.8415). This study demonstrates that the Framingham risk score based on data from a non-Korean population can lead to the underestimation of the prediction risk of hypertension. J Clin Hypertens (Greenwich).

BackgroundScreening for risk of type 2 diabetes mellitus (T2DM) is an important public health issue. Previous studies report that fasting plasma glucose (FPG) and triglyceride (TG)-related indices, such as lipid accumulation product (LAP) and the product of fasting glucose and triglyceride (TyG index), are associated with incident T2DM. We aimed to evaluate whether FPG or TG-related indices can improve the predictive ability of a diabetes risk model for middle-aged Koreans.Methods7708 Koreans aged 40–69 years without diabetes at baseline were eligible from the Korean Genome and Epidemiology Study. The overall cumulative incidence of T2DM was 21.1% (766 cases) in men and 19.6% (797 cases) in women. Therefore, the overall cumulative incidence of T2DM was 20.3% (1563 cases). Multiple logistic regression analysis was conducted to compare the odds ratios (ORs) for incident T2DM for each index. The area under the receiver operating characteristic curve (AROC), continuous net reclassification improvement (cNRI), and integrated discrimination improvement (IDI) were calculated when each measure was added to the basic risk model for diabetes.ResultsAll the TG-related indices and FPG were more strongly associated with incident T2DM than WC in our study population. The adjusted ORs for the highest quartiles of WC, TG, FPG, LAP, and TyG index compared to the lowest, were 1.64 (95% CI, 1.13–2.38), 2.03 (1.59–2.61), 3.85 (2.99–4.97), 2.47 (1.82–3.34), and 2.79 (2.16–3.60) in men, and 1.17 (0.83–1.65), 2.42 (1.90–3.08), 2.15 (1.71–2.71), 2.44 (1.82–3.26), and 2.85 (2.22–3.66) in women, respectively. The addition of TG-related parameters or FPG, but not WC, to the basic risk model for T2DM (including age, body mass index, family history of diabetes, hypertension, current smoking, current drinking, and regular exercise) significantly increased cNRI, IDI, and AROC in both sexes.ConclusionsAdding either TyG index or FPG into the basic risk model for T2DM increases its prediction and reclassification ability. Compared to FPG, TyG index was a more robust T2DM predictor in the stratified sex and fasting glucose level. Therefore, TyG index should be considered as a screening tool for identification of people at high risk for T2DM in practice.

BackgroundHypertension is a leading cause of cardiovascular events. We examined whether there was a gender difference in the association between SES, measured by education and income, and hypertension incidence.MethodsData for 2596 men and 2686 women aged 40–69 years without hypertension at baseline from the Korean Genome and Epidemiology Study (KoGES) were analyzed. Participants had two follow-up examinations during 4 years, and were classified into three categories by self-reported educational attainment: ≥ 10 years, 7–9 years, and 0–6 years, and monthly household income (×10,000 Korean Won): ≥ 200, 100–199, and <100. The association between SES and incidence hypertension was examined by Cox’s proportional hazard regression analyses.ResultsAdjusting for conventional risk factors, compared with the high education group (reference), the hazard ratios (95 % confidence interval) for incident hypertension across the education categories were 1.54 (1.16–2.06) and 1.80 (1.36–2.38) in women and 1.15 (0.92–1.43), and 1.08 (0.84–1.38) in men. Women with the low household income were more likely to have hypertension than those with the high household income and incident hypertension had an inverse association with household income level in women: multivariate adjusted hazard ratios were 1.00 (reference), 1.10 (0.83–1.45), and 1.63 (0.75–2.16). Men with medium income were less likely to have hypertension compared with those with high income (0.76, 0.61–0.90).ConclusionsEducational level and economic status had stronger impacts on hypertension in Korean women than men. Thus, a stratified approach for women of low socioeconomic status, especially those with low educational attainment, is needed for the prevention of hypertension.

Background:The aim of this study was to develop a risk score to predict the 4-year risk of diabetes in a middleaged Korean cohort. Methods and Results:Participants without diabetes (6,342 participants, aged 40-69 years) were included and biennial follow ups were conducted. A logistic regression analysis was used to construct the models. The basic model was based on simple information such as age, parental or sibling history of diabetes, smoking status, body mass index, and hypertension, while clinical model 1 was constructed by adding biochemical tests such as fasting plasma glucose, high-density lipoprotein-cholesterol and triglycerides to the basic model; clinical model 2 further added glycated hemoglobin (HbA1c) to clinical model 1. The model accuracy was assessed using area under a receiver operating characteristic (AROC) curve and the Hosmer-Lemeshow statistics. Both net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated to determine the contribution of HbA1c. Two clinical models improved model discrimination (AROC=0.75 and 0.77) when compared with the basic model (AROC=0.65). The addition of HbA1c to clinical model 1 increased AROC by only 0.02 despite its high impact on the prediction of diabetes (odds ratio=2.66). However, the NRI and IDI were significantly improved with the addition of HbA1c. Therefore, a risk score system was developed to estimate the 4-year risk of diabetes based on clinical model 2. Conclusions:A risk score derived from simple biochemical examinations including HbA1c can help identify those at a high risk of diabetes in a middle-aged Korean cohort. (Circ J 2012; 76: 1904 - 1910

Atrial fibrillation (AF) is a major risk factor for ischemic stroke and associated with a 5-fold higher risk of stroke. In this retrospective cohort study, the incidence of and risk factors for ischemic stroke in patients with AF were identified. All patients (≥30 years old) without previous stroke who were diagnosed with AF in 2007–2013 were selected from the National Health Insurance Service-National Sample Cohort. To identify factors that influenced ischemic stroke risk, Cox proportional hazard regression analysis was conducted. During a mean follow-up duration of 3.2 years, 1022 (9.6%) patients were diagnosed with ischemic stroke. The overall incidence rate of ischemic stroke was 30.8/1000 person-years. Of all the ischemic stroke that occurred during the follow-up period, 61.0% occurred within 1-year after AF diagnosis. Of the patients with CHA2DS2-VASc score of ≥2, only 13.6% were receiving warfarin therapy within 30 days after AF diagnosis. Relative to no antithrombotic therapy, warfarin treatment for >90 days before the index event (ischemic stroke in stroke patients and death/study end in non-stroke patients) associated with decreased ischemic stroke risk (Hazard Ratio = 0.41, 95%confidence intervals = 0.32–0.53). Heart failure, hypertension, and diabetes mellitus associated with greater ischemic stroke risk. AF patients in Korea had a higher ischemic stroke incidence rate than patients in other countries and ischemic stroke commonly occurred at early phase after AF diagnosis. Long-term (>90 days) continuous warfarin treatment may be beneficial for AF patients. However, warfarin treatment rates were very low. To prevent stroke, programs that actively detect AF and provide anticoagulation therapy are needed.