Eunsun Jang

Increasing trends in hospital care burden of atrial fibrillation in Korea, 2006 through 2015

Objective Temporal changes in the healthcare burden of atrial fibrillation (AF) are less well known in rapidly ageing Asian countries. We examined trends in hospitalisations, costs, treatment patterns and outcomes related to AF in Korea. Methods Using the National Health Insurance Service (NHIS) database involving the entire adult Korean population (n=41 701 269 in 2015), we analysed a nationwide AF cohort representing 931u2009138 patients with AF. We studied all hospitalisations due to AF from 2006 to 2015. Results Overall, hospitalisations for AF increased by 420% from 767 to 3986 per 1u2009million Korean population from 2006 to 2015. Most admissions occurred in patients aged ≥70 years, and the most frequent coexisting conditions were hypertension, heart failure and chronic obstructive pulmonary disease. Hospitalisations mainly due to major bleeding and AF control increased, whereas hospitalisations mainly due to ischaemic stroke and myocardial infarction decreased. The total cost of care increased even after adjustment for inflation from €68.4u2009million in 2006 to €388.4u2009million in 2015, equivalent to 0.78% of the Korean NHIS total expenditure. Overall in-hospital mortality decreased from 7.5% in 2006 to 4.3% in 2015. The in-hospital mortality was highest in patients ≥80 years of age (7.7%) and in patients with chronic kidney disease (7.4%). Conclusions AF hospitalisations have increased exponentially over the past 10 years in Korea, in association with an increase in comorbid chronic diseases. Mortality associated with AF hospitalisations decreased during the last decade, but hospitalisation costs have markedly increased.

Dynamic Changes of CHA2DS2-VASc Score and the Risk of Ischaemic Stroke in Asian Patients with Atrial Fibrillation: A Nationwide Cohort Study

BACKGROUNDnu2003Stroke risk in atrial fibrillation (AF) is often assessed at initial presentation, and risk stratification performed as a one off. In validation studies of risk prediction, baseline values are often used to predict events that occur many years later. Many clinical variables have dynamic changes over time, as the patient is followed up. These dynamic changes in risk factors may increase the CHA2DS2-VASc score, stroke risk category and absolute ischaemic stroke rate.nnnOBJECTIVEnu2003This article evaluates the dynamic changes of CHA2DS2-VASc variables and its effect on prediction of stroke risk.nnnPATIENTS AND METHODSnu2003From the Korea National Health Insurance Service database, a total of 167,262 oral anticoagulant-naive non-valvular AF patients aged ≥ 18 years old were enrolled between January 1, 2002, and December 31, 2005. These patients were followed up until December 31, 2015.nnnRESULTSnu2003At baseline, the proportions of subjects categorized as low, intermediate or high risk by CHA2DS2-VASc score were 15.4, 10.6 and 74.0%, respectively. Mean CHA2DS2-VASc score increased annually by 0.14, particularly due to age and hypertension. During follow-up of 10 years, 46.6% of low-risk patients and 72.0% of intermediate risk patients were re-classified to higher stroke risk categories. Among the original low-risk patients, annual ischaemic stroke rates were significantly higher in the re-classified intermediate (1.17 per 100 person-years, pu2009<u20090.001) or re-classified high-risk groups (1.44 per 100 person-years, pu2009=u20090.048) than consistently low-risk group (0.29 per 100 person-years). The most recent CHA2DS2-VASc score and the score change with the longest follow-up had the best prediction for ischaemic stroke.nnnCONCLUSIONnu2003In AF patients, stroke risk as assessed by the CHA2DS2-VASc score is dynamic and changes over time. Rates of ischaemic stroke increased when patients accumulated risk factors, and were re-classified into higher CHA2DS2-VASc score categories. Stroke risk assessment is needed at every patient contact, as accumulation of risk factors with increasing CHA2DS2-VASc score translates to greater stroke risks over time.

Variations of Prevalence and Incidence of Atrial Fibrillation and Oral Anticoagulation Rate According to Different Analysis Approaches

The reported incidence and prevalence of atrial fibrillation (AF) has been inconsistent across published studies. Using the National Health Insurance Service database of Korea, the prevalence and incidence of AF, and oral anticoagulation (OAC) use of AF patients were explored according to three different approaches; ‘formal approach’, considering individual AF diagnosis and mortality; ‘limited diagnosis approach’, using upper 5 main diagnosis; and ‘medical use approach’, using the number of medical use AF population by year without considering individual AF history and mortality. The AF prevalence progressively increased by 2.46-fold from 0.50% in 2004 to 1.54% in 2015 when using a ‘formal approach’ (p for trend <0.001). The overall prevalence was 1.09% and 0.97% when using a ‘formal approach’ and ‘limited diagnosis approaches’, respectively. Overall prevalence decreased to 0.52% with a ‘medical use approach’. The trend of annual AF incidence was stable when using a ‘formal approach’, but increased by 15% when using a ‘medical use approach’. OAC rate in 2015 was 2.1 times higher when using a ‘medical use approach’ compared to using a ‘formal approach’ (40.3% vs. 19.1%, pu2009<u20090.001). Given the wide variability in prevalence and incidence figures with different analysis approaches, careful attention to the analysis methodology is needed.

Ideal Blood Pressure in Patients With Atrial Fibrillation

BACKGROUNDnThe 2017 American College of Cardiology/American Heart Association (ACC/AHA) Guideline for High Blood Pressure in Adults redefined hypertension as systolic blood pressure (BP)xa0≥130xa0mmxa0Hg or diastolic BPxa0≥80xa0mmxa0Hg. The optimal BP for patients with atrial fibrillation (AF) is uncertain.nnnOBJECTIVESnThe goal of this study was to investigate the impacts of the 2017 ACC/AHA guideline and to determine the ideal BP threshold for the management of high BP in patients with AF.nnnMETHODSnThis study analyzed data for 298,374 Korean adults with oral anticoagulant-naive, nonvalvular AF obtained from the National Health Insurance Service database from 2005 toxa02015.nnnRESULTSnAccording to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure guideline, 62.2% of the individuals in our sample had hypertension. After applying the 2017 ACC/AHA guideline, 79.4% had hypertension, including 17.2% with newly redefined hypertension (130 to 139/80 to 89xa0mmxa0Hg). Those with newly redefined hypertension had greater risks of major cardiovascular events (hazard ratio: 1.07; 95% confidence interval: 1.04 to 1.10; pxa0< 0.001), ischemic stroke, intracranial hemorrhage, and heart failure admission, compared with nonhypertensive patients (<130/80xa0mmxa0Hg). Among patients with AF undergoing hypertension treatment, patients with BPxa0≥130/80xa0mmxa0Hg orxa0<120/80xa0mmxa0Hg were at significantly higher risks of major cardiovascular events than patients with BP of 120 to 129/<80xa0mmxa0Hg.nnnCONCLUSIONSnPatients with AF and newly redefined hypertension according to the 2017 ACC/AHA guideline were at higher risk of major cardiovascular events, suggesting that the new BP threshold is beneficial for timely diagnosis and intervention. BP of 120 to 129/<80xa0mmxa0Hg was the optimal BP treatment target for patients with AF undergoing hypertension treatment.

A Simple Clinical Risk Score (C2HEST) for Predicting Incident Atrial Fibrillation in Asian Subjects

BACKGROUND: The incidence of atrial fibrillation (AF) is increasing, conferring a major health‐care issue in Asia. No risk score for predicting incident AF has been specifically developed in Asian subjects. Our aim was to investigate risk factors for incident AF in Asian subjects and to combine them into a simple clinical risk score. METHODS: Risk factors for incident AF were analyzed in 471,446 subjects from the Chinese Yunnan Insurance Database (internal derivation cohort) and then combined into a simple clinical risk score. External application of the new score was performed in 451,199 subjects from the Korean National Health Insurance Service (external cohort). RESULTS: In the internal cohort, structural heart disease (SHD), heart failure (HF), age ≥ 75 years, coronary artery disease (CAD), hyperthyroidism, COPD, and hypertension were associated with incident AF. Given the low prevalence and the strong association of SHD with incident AF (hazard ratio, 26.07; 95% CI, 18.22‐37.30; P < .001), these patients should be independently considered as high risk for AF and were excluded from the analysis. The remaining predictors were combined into the new simple C2HEST score: C2: CAD/COPD (1 point each); H: hypertension (1 point); E: elderly (age ≥ 75 years, 2 points); S: systolic HF (2 points); and T: thyroid disease (hyperthyroidism, 1 point). The C2HEST score showed good discrimination with the area under the curve (AUC) of 0.75 (95% CI, 0.73‐0.77) and had good calibration (P = .774). The score was internally validated by bootstrap sampling procedure, giving an AUC of 0.75 (95% CI, 0.73‐0.77). External application gave an AUC of 0.65 (95% CI, 0.65‐0.66). The C2HEST score was superior to CHADS2 and CHA2DS2‐VASc scores in both cohorts in predicting incident AF. CONCLUSIONS: We have developed and validated the C2HEST score as a simple clinical tool to assess the individual risk of developing AF in the Asian population without SHD.

10-year nationwide trends of the incidence, prevalence, and adverse outcomes of non-valvular atrial fibrillation nationwide health insurance data covering the entire Korean population

Background Most data on the clinical epidemiology of atrial fibrillation (AF) are reported from Western populations, and data for Asians are limited. We aimed to investigate the 10‐year trends of the prevalence and incidence of non‐valvular AF and provide prevalence projections till 2060 in Korea. We also investigated the annual risks of adverse outcomes among patients with AF. Methods Using the Korean National Health Insurance Service database involving the entire Korean population, a total of 679,416 adults with newly diagnosed AF were identified from 2006 to 2015. The incidence and prevalence of AF and risk of adverse outcomes following AF onset were assessed. Results The prevalence of AF progressively increased by 2.10‐fold from 0.73% in 2006 to 1.53% in 2015. The trend of its incidence was flat with a 10‐year overall incidence of 1.77 per 1,000 person‐years. The prevalence of AF is expected to reach 5.81% (2,290,591 patients with AF) in 2060. For a decade, the risk of all‐cause mortality following AF declined by 30% (adjusted hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.68–0.72), heart failure by 52% (adjusted HR: 0.48, 95% CI: 0.44–0.51), and ischemic stroke by 9% (adjusted HR: 0.91, 95% CI: 0.88–0.93). Conclusions The burden of AF among Asian patients is increasing. Although the overall risks of cardiovascular events and death following AF onset have decreased over a decade, the event rates are still high. Optimized management of any associated comorbidities should be part of the holistic management approach for patients with AF.