Korea National Health Insurance Service Research Articles

Low vision and the risk of dementia: a nationwide population-based cohort study

Recent studies suggested that an association exists between vision loss and cognitive impairment, although it is still vague whether there are causal relationships or direct association between low vision and dementia. We were to investigate the association between low vision and dementia in the Korean population using the National Health Insurance Service (NHIS) database. We analyzed the data of 6,029,657 subjects aged ≥40 years, drawn from Korea National Health Insurance Service. The hazard ratio (HRs) and 95% confidence interval (CIs) of dementia, Alzheimer’s disease (AD), and Vascular dementia (VD) were estimated using multivariable Cox proportional hazards regression models. Statistical analysis showed that subjects with more severe visual impairments have a higher risk of dementia, AD, and VD after adjusting for compounding variables. The HRs of dementia increased significantly as visual acuity worsened (HRs 1.444 [95% CIs 1.415–1.473] for visual acuity (VA) < 1.0, 1.734 [1.693–1.777] for VA < 0.3, 1.727 [1.686–1.770] for VA < 0.1 and 1.991[1.902–2.085] for visual loss). Baseline visual loss and visual impairment were positively associated with the risk of dementia, AD, and VD. From the results of this nationwide population-based cohort study, we suggest that there is a significant increase in the incidence of dementia in subjects with low vision.

External Airborne-agent Exposure Increase Risk of Digestive Tract Cancer

Previous studies have suggested that in addition to respiratory system cancers, exposure to external airborne agents (EAAs) may also affect the risk of digestive tract cancer. However, previous epidemiological studies have been limited. To clarify this relationship, we conducted a Workers’ Korea National Health Insurance Service cohort study. The EAA exposure group comprised participants who had ever visited a hospital as an inpatient for ‘lung diseases due to external agents’. The reference population comprised men from the general working population. The EAA exposure group and reference group included a total of 98,666 and 79,959,286 person-years, respectively. Age-adjusted standardized incident rates (SIRs) with 95% confidence intervals (95%CI) were calculated for each 5-year age stratum. The SIR (95% CI) of EAA exposure was 1.30 (1.19–1.38) for all digestive tract cancers. The highest risk associated with EAA exposure was observed for oral cancer, followed by esophageal and stomach cancers [SIRs (95%CI): 3.96 (3.02–4.78), 3.47(2.60–4.25), and 1.34(1.17–1.47), respectively.] These statistically significant associations did not be attenuated in a subgroup analysis using logistic regression adjusted for age, smoking and alcohol consumption. Our findings suggest that EAA exposure should address risk reduction of both digestive tract and respiratory system cancers.

Anti-fracture Efficacy of Monthly Risedronate Compared with That of Weekly Risedronate in Postmenopausal Korean Women with Osteoporosis: A Nationwide Cohort Study.

BackgroundIntermittent dosing regimens for oral risedronate (once-monthly and once-weekly) were developed for patient convenience. While several studies have reported the anti-fracture efficacy of weekly dosing, few have assessed monthly dosing. The lower efficacy of monthly dosing has been previously suggested. The aim of this study was to compare the anti-fracture efficacy of monthly and weekly dosing.MethodsWe obtained information from the Korea National Health Insurance Service database from 2012 to 2017 of Korean women of ≥50 years of age who used weekly or monthly risedronate. We compared the time of occurrence of the first osteoporotic fracture after the first prescription of risedronate. Using a Cox proportional model, we assessed incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for fractures at any site, and the hip, vertebral, and non-vertebral sites between both regimens. Propensity score weighting was used to balance the treatment groups.ResultsThe study populations were distributed according to dosing frequency (monthly, 27,329; weekly, 47,652). There was no significant difference in the incidence rate of new fractures in any site (IRR, 1.008; 95% CI,0.963–1.055; P=0.737), hip (IRR, 0.999; 95% CI, 0.769–1.298; P=0.996), vertebral (IRR, 0.962; 95% CI, 0.890–1.040; P=0.330), or non-vertebral (1.022; 95% CI, 0.968–1.078; P=0.439) sites between monthly and weekly risedronate.ConclusionThe anti-fracture efficacy at any site and the examined individual sites was similar for the monthly and weekly risedronate regimens. Large-scale randomized controlled trials are required for confirmation.

Comparison between urban and rural mortality in patients with acute myocardial infarction: a nationwide longitudinal cohort study in South Korea

ObjectivesThis study investigated the risk associated with interhospital transfer of patients with acute myocardial infarction (AMI) and clinical outcomes according to the location of the patient’ residence.DesignA nationwide longitudinal cohort.SettingNational...

Abstract TP186: Incidence and Risk Factors for Stroke and All-Cause Mortality in Korean Adults Congenital Heart Diseases

Objective: To compare incidence of ischemic stroke, hemorrhagic stroke and all-cause mortality in Korean adults congenital heart disease (ACHD) to that of control and scrutinize risk factors for these outcomes. Methods: Subjects aged over 20 were collected from the Korea National Health Insurance Service from 2006 through 2017. ACHD group as case was extracted from the diagnosis records related to CHD according to the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD 10). Those without CHD (control group) was selected as 4 controls for each patient through random sampling. We compared incidence rate of ischemic stroke, hemorrhagic stroke and all-cause mortality. Cox proportional hazard models were used to investigate relevant risk factors for each of outcomes. Results: Case and control group were 49,445 and 249,649, respectively. Age-adjusted rates of ischemic stroke, hemorrhagic stroke and all-cause mortality in case was by about 4 times more higher than those of control. Cumulative survival plot demonstrated that ACHD was associated with ischemic stroke (HR 1.31 95% CI 1.25-1.36), hemorrhagic stroke (HR 1.49 95% CI 1.36-1.63), and all-cause mortality (HR 1.41 95% CI 1.35-1.46). Case group was associated with younger age, female, hypertension, diabetes mellitus, coronary artery disease, heart failure, atrial fibrillation (all p &lt;.001). In Cox proportional hazard model for ischemic stroke, diabetes (HR 2.13 95% CI 1.93-2.35) and coararctation of aorta (HR 1.54 95% CI 1.13 - 2.09) carried highest risk. In multivariable analysis for hemorrhagic stroke, hypertension (HR 2.28 95% CI 1.74-2.98) was highest risk factor. Multivariable analysis for all-cause mortality showed that congestive heart failure (HR 1.78 95% CI 1.65-1.92) and Eisenmenger syndrome (HR 2.91 95% CI 2.53-3.35) was highest risk factor. Conclusions: Korean ACHD patients have significantly higher incidence of co-morbidities including hypertension, diabetes mellitus, several heart diseases. They have a higher tendency of ischemic, hemorrhagic stroke and mortality. These findings suggest that medical surveillance and risk factor management is sustainedly needed for ACHD patients to reduce stroke and mortality in the future.

Height is associated with incident atrial fibrillation in a large Asian cohort

BackgroundAlthough increased height is associated with a risk of atrial fibrillation (AF), the mechanism is not well understood. We aimed to explore whether this association varies with metabolic conditions. Methods and resultsWe used the database from the 14-year Korea National Health Insurance Service–National Sample Cohort. The data of 368,206 adults older than 20 years who received a health check-up were analyzed to explore the association of height and AF risk. Cox proportional hazards regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of height with the risk of AF.During the median follow up duration of 8.46 years, 2641 (0.72%) patients were diagnosed with AF at 3,070,724 person-years. Overall, greater height was significantly associated with AF risk (HR per 5 cm, 1.22; 95% CI, 1.03–1.05). The association did not vary with age, sex, obesity, hypertension, and diabetes. ConclusionMetabolic conditions do not affect the higher risk of AF in tall people.

A simple screening score to predict diabetes in cancer patients: A Korean nationwide population-based cohort study.

Many cancer patients develop diabetes, which may result in reduction of chemotherapy effectiveness and increased infection risk and cardiovascular mortality. Diabetes may also increase the risks of chemotherapy-related toxicity and post-operative mortality, or represent an obstacle to optimal cancer treatment. However, the clinical predictors of diabetes in cancer patients remain largely unknown. Therefore, the aim of our study was to evaluate the risk factors for developing diabetes and construct a nomogram to predict diabetes in cancer patients.We investigated patients from a national sample cohort obtained from the Korea National Health Insurance Service (KNHIS), which included 2% of the Korean population. Patients who had undergone routine medical evaluation by the KNHIS between 2004 and 2008 and been hospitalized due to cancer (ICD-10 codes C00–97) during the past 3 years were included. After excluding patients with type 2 diabetes and missing data, 10,899 patients were enrolled and followed-up until 2013. A total of 7630 (70%) patients were assigned as the training cohort and used to construct the nomogram which was based on a multivariable logistic regression model. The remaining patients (n = 3269) were used as the validation cohort.The incidence rate of diabetes was 12.1 per 1000 person-years over a mean follow-up of 6.6 ± 1.8 years. Significant risk factors for developing diabetes were age, sex, obesity, fasting plasma glucose, hypertension, and hypercholesterolmia. A nomogram was constructed using these variables and internally validated. The area under the curve was 0.70 (95% confidence interval, .666-.730, P < .0001) and the calibration plot showed agreement between the actual and nomogram-predicted diabetes probabilities.The nomogram developed in this study is easy to use and convenient for identifying cancer patients at high-risk for type 2 diabetes, enabling early type 2 diabetes screening and management.

Association between obstructive sleep apnoea and breast cancer: The Korean National Health Insurance Service Data 2007\u20132014

Some studies have argued that obstructive sleep apnoea (OSA) increases the risk of breast cancer. However, the results are often conflicting. This study aimed to investigate associations between OSA and breast cancer incidence using the Korea National Health Insurance Service (KNHIS) database. This retrospective cohort study analyzed data from the KNHIS database. A total of 45,699 women (≥20 years of age) newly diagnosed with OSA between 2007 and 2014 were included. The control groups were a 5-fold, age-matched women who had not been diagnosed with OSA. Mean follow-up duration was 3.7 ± 2.3 years. The primary endpoint was newly diagnosed breast cancer. The breast cancer hazard ratio (95% confidence interval) was calculated for patients with OSA and compared with that of the control group. The incidence of breast cancer among patients with OSA was significantly higher than that among the controls (1.20 [1.04–1.39]). In particular, the incidence of breast cancer was higher among patients aged ≥65 years (1.72 [1.10–2.71]). The result suggests that OSA may be a risk factor for breast cancer in women.

The incidence and etiology of sixth cranial nerve palsy in Koreans: A 10-year nationwide cohort study

We aimed to investigate the incidence, prevalence, and etiology of sixth cranial nerve (CN6) palsy in the general Korean population. The nationally representative dataset of the Korea National Health Insurance Service–National Sample Cohort from 2006 through 2015 was analyzed. The incidence and prevalence of CN6 palsy were estimated in the cohort population, confirming that incident cases of CN6 palsy involved a preceding disease-free period of ≥4 years. The etiologies of CN6 palsy were presumed using comorbidity conditions. Among the 1,108,256 cohort subjects, CN6 palsy developed in 486 patients during the 10-year follow-up. The overall incidence of CN6 palsy was estimated to be 4.66 per 100,000 person-years (95% confidence interval [CI], 4.26–5.08) in the general population. This incidence increased with age, accelerating after 60 years of age and peaking at 70–74 years of age. The mean male-to-female incidence ratio was estimated as 1.41 in the whole population, and the incidence and prevalence of CN6 palsy showed an increasing trend over time in the study period. Surgical incidence for CN6 palsy was only 0.19 per 100,000 person-years (95% CI, 0.12–0.29). The etiologies were presumed to be vascular (56.6%), idiopathic (27.2%), neoplastic (5.6%), and traumatic (4.9%). In conclusion, the incidence of CN6 palsy increases with age, peaking at around 70 years, and shows a mild male predominance in Koreans.

Prevalence of Intracranial Aneurysms in Patients With Systemic Vessel Aneurysms: A Nationwide Cohort Study.

Background and Purpose- Most aneurysms are a focal manifestation of a systemic condition. Some reports have suggested genetic and environmental factors may play a role in pathogenesis. The aim of the present study was to evaluate the prevalence of intracranial aneurysms (IA) in a large cohort of patients with other systemic vessel aneurysms and dissections (OVAD) and identify potential risk factors for IA in this population. Methods- We defined OVAD as systemic vessel aneurysms, excluding aortic dissections and aneurysms. A cohort of 1.1 million patients was extracted from the population-based cohort from the Korea National Health Insurance Service, which holds almost all medical data including diagnostic codes, procedures, and personal information. Using χ2 or Fisher exact test, the prevalence of the IA concerning OVAD status was analyzed. Results- In OVAD individuals, 25.7% (261/1017) of patients had been concurrently diagnosed with IA. The odds ratios for having concurrent IA in patients with OVAD were 56.31 (95% CI, 48.821-64.949; P=0.000). OVAD patients with dyslipidemia were >7× likely to be affected by IA (adjusted odds ratio, 7.7 [95% CI, 6.59-9.01]; P=0.000). Hypertension, diabetes mellitus, old age (>60 years), and male sex had increased odds for having concurrent IA by 5.89, 3.48, 1.83, and 1.35, respectively. Subgroup analysis with socioeconomic or disability revealed that the prevalence of IA was significantly higher in all groups. Uncertainty regarding the temporal sequence of onset and lack of detail on disease severity and subtype prevented more conclusive results. Conclusions- Patients with OVAD have a higher prevalence of IA than control groups. Therefore, we may approach aneurysms as systemic disease, and further investigations about their pathophysiology must follow.

Risk Factors for Colorectal Cancer in Korea: A Population-Based Retrospective Cohort Study.

PurposeThe incidence of colorectal cancer in Korea has recently increased, making it the second most common cancer in men and the third most common cancer in women. Risk factors for colorectal cancer have been studied worldwide, but risk factors specific for the Korean population have not been established. In this study, we investigated incidence trends and risk factors of colorectal cancer in Korea.MethodsA total of 8,846,749 subjects were included. Colorectal cancer incidence was investigated using Korea National Health Insurance Service claim data from 2004 to 2014. Colorectal cancer diagnoses were obtained by evaluating colorectal cancer diagnostic codes and the cancer registry for cost sharing. Risk factor identification for colorectal cancer was obtained from National Health Examination data from 2004 to 2005. Cox proportional hazard model statistical analysis was used to determine risk factors of colorectal cancer.ResultsThe incidence of colorectal cancer gradually increased from 2006 to 2014 (from 45.4/100,000 to 54.5/100,000). There was a predominance among men (1.47:1), but incidence trends were similar in both sexes. Old age, high body mass index, and no history of colonoscopy were identified as risk factors in both sexes. High fasting blood glucose, familial history of cancer, frequent alcohol intake, and current smoker were identified as risk factors, especially in men.ConclusionThe incidence of colorectal cancer has been increasing in Korea. Colonoscopy screening was a protective factor for colorectal cancer, and active use of colonoscopy may reduce incidence. Early diagnosis and care are important, particularly for the high-risk group.

Incidence and mortality of subsequent vertebral fractures: analysis of claims data of the Korea National Health Insurance Service from 2007 to 2016

BACKGROUND CONTEXTVertebral fracture is related to an increased risk for subsequent and recurrent osteoporotic fracture as well as increased mortality. However, no study has investigated the exact incidence and mortality of subsequent vertebral fractures. OBJECTIVEThe purpose of our study was to determine trends in the incidence and mortality of subsequent vertebral fractures after first-time vertebral fracture in Koreans older than 50 years using the national claims database. STUDY DESIGNRetrospective cohort study. PATIENT SAMPLEData from the Korea National Health Insurance Service database from 2007 to 2016. OUTCOME MEASURESThe incidence of subsequent vertebral fracture during a 4-year follow-up period. The mortality and standardized mortality ratio (SMR) after subsequent vertebral fractures during the 1-year period after fracture were also determined. Analysis was restricted to patients older than 50 years. METHODSThe national claims data set was analyzed to find all new visits and revisits after 6 months from the last claim to a hospital or clinic for vertebral fractures and revisits in men and women aged 50 years or older between 2007 and 2016. The number of first-time vertebral fractures in 2012 was investigated to determine subsequent vertebral fractures. The incidence, mortality rates, and SMR of subsequent vertebral fractures were calculated. There were no sources of funding and no conflicts of interest associated with this study. RESULTSDuring the 4-year follow-up period, the overall cumulative incidence of subsequent vertebral fractures were 27.53%. According to sex, the cumulative incidence of subsequent vertebral fractures was 20.09% in men and 29.98% in women. The cumulative mortality rate over the first year after subsequent vertebral fractures was 5%. The mortality rates over 1 year were 10.04% for men and 3.81% for women. The overall SMR at the 1-year follow-up after subsequent vertebral fractures was 10.58 (95% confidence interval: 9.29–12.05) in men and 3.88 (95% confidence interval: 3.5–4.3) in women. CONCLUSIONSOur study showed that subsequent vertebral fractures were more common in women, with an incidence rate of 29.98% over 4 years. However, the mortality rate was higher in men, reaching 10.04% in 1 year. Subsequent vertebral fractures occurred in large numbers, and the mortality rates were relatively high. Thus, first vertebral fracture may be considered as an early warning of high risk for future subsequent vertebral fractures, especially in women.

Metoclopramide and Levosulpiride Use and Subsequent Levodopa Prescription in the Korean Elderly: The Prescribing Cascade.

The aim of this study was to investigate the prescribing cascade phenomenon of dopaminergic drugs such as levodopa in the management of gastroprokinetic drugs induced parkinsonism. Based on the Korea National Health Insurance Service (NHIS)-Senior Cohort Database, we analyzed patients aged ≥65 years, between 2009 and 2013, who obtained new prescriptions for levodopa through the NHIS during this period. Those who were prescribed levodopa from 2002 to 2008 were excluded, only patients who were prescribed metoclopramide and levosulpiride within 90 days of receiving the levodopa prescription were included. Those who did not receive levodopa were used as a control group for 1:3 age and sex matching. We assessed 1824 and 1197 levodopa cases for metoclopramide and levosulpiride use, respectively. The matched controls for each levodopa case were 5472 and 3591, respectively. We used conditional logistic regression to determine the odds ratio (OR) for initiation of levodopa therapy in patients using metoclopramide and levosulpiride, relative to nonusers, after adjusting for age, sex, and exposure to antipsychotic medication. Both metoclopramide (OR = 3.04; 95% confidence interval, CI, 2.46–3.77) and levosulpiride (OR = 3.32; 95% CI, 2.56–4.3) users were three times more likely to begin using medication containing levodopa, compared to nonusers. Metoclopramide and levosulpiride were frequently prescribed within 90 days of receiving a prescription for levodopa. Before prescribing levodopa, it should be considered whether the adverse event is actually a side effect caused by metoclopramide and levosulpiride.

Improved Population-Based Clinical Outcomes of Patients with Atrial Fibrillation by Compliance with the Simple ABC (Atrial Fibrillation Better Care) Pathway for Integrated Care Management: A Nationwide Cohort Study.

An integrated care approach might be of benefit for clinical outcomes of patients with atrial fibrillation (AF). This study evaluated whether compliance with the Atrial fibrillation Better Care (ABC) pathway for integrated care management ("A" Avoid stroke; "B" Better symptom management; "C" Cardiovascular risk and Comorbidity optimization) would improve population-based clinical outcomes in a nationwide AF cohort. From the Korea National Health Insurance Service database, a total of 204,842 nonvalvular AF patients were enrolled between January 1, 2005 and December 31, 2015. Patients that fulfilled all criteria of the ABC pathway were defined as the "ABC" group, and those who did not were the "Non-ABC" group.Over a mean follow-up of 6.2 ± 3.5 years, the ABC pathway compliant group had lower rates of all-cause death (0.80 vs. 2.72 per 100 person-years, p < 0.001) and the composite outcome of "death, ischemic stroke, major bleeding, and myocardial infarction" (2.34 vs. 5.92 per 100 person-years, p < 0.001) compared with the Non-ABC compliant group. Adjusted Cox multivariable regression showed that the ABC group had a significantly lower risk of all-cause death (adjusted hazard ratio [HR] 0.82; 95% confidence interval [CI], 0.78-0.86) and the composite outcome (adjusted HR 0.86; 95% CI, 0.83-0.89). With the increasing numbers of ABC pathway criteria fulfilled, the risk of all-cause death and composite outcome were progressively lowered. In the first study of a nationwide population cohort, we show that compliance with the simple ABC pathway is associated with improved clinically relevant outcomes of patients with AF. Given the high health care burden associated with AF, such a streamlined holistic approach to AF management should be implemented, to improve the care of such patients.

Effect of hypertension duration and blood pressure level on ischaemic stroke risk in atrial fibrillation: nationwide data covering the entire Korean population.

There are a paucity of data on the association of duration of hypertension and blood pressure (BP) level with risk of ischaemic stroke in patients with atrial fibrillation (AF). Our objective was to investigate the association between duration of hypertension and secondly, BP levels with risk of ischaemic stroke among patients with AF. A total of 246459 oral anticoagulant-naïve non-valvular AF patients were enrolled from Korea National Health Insurance Service (NHIS) database (2005-2015). The risk of ischaemic stroke according to the duration of hypertension and systolic BP (SBP) levels were assessed. One-year increase of hypertension duration continuously increased the adjusted risk of ischaemic stroke (95% confidence interval 1.07-1.09) until 7 years, and reached a plateau with adjusted hazard ratio of 1.6. Risk of ischaemic stroke increased linearly with the increase of hypertension duration in patients younger than 65 years of age, whereas the risk reached a plateau in patients aged 65 years or older. In all baseline and pre-AF average SBP subgroups, longer duration of hypertension before AF was associated with higher ischaemic stroke risk than shorter duration of hypertension (all P-values for trends <0.01). However, the effect of long-term hypertension was not observed in patients with strictly well-controlled pre-AF average SBP of less than 120 mmHg. The increase of hypertension duration was associated with the increased risk of ischaemic stroke. However, this long-term effect of hypertension duration can be attenuated by long-term strict SBP control throughout the entire duration of hypertension.

Blood pressure level associated with lowest cardiovascular event in hypertensive diabetic patients.

The ACCORD BP trial failed to show the benefit of strict blood pressure (BP) control on cardiovascular events in diabetics with high cardiovascular risk. However, this result cannot be generalized to all diabetics. We investigated whether lower mean BP in diabetic people with hypertension is associated with better prognosis. Participants from the Korea National Health Insurance Service Health Examinee Cohort who were diagnosed with diabetes and hypertension between 2003 and 2006 were included in the analysis (N = 7926). Mortality and cardiovascular events were compared among three groups according to mean SBP (<130, 130-<140, ≥140 mmHg) and mean DBP (<80, 80-<90, ≥ 90 mmHg) recorded during follow-up health examinations for up to 11 years. Significant reductions in the risk of all-cause death, nonfatal myocardial infarction (MI), nonfatal stroke, and end-stage renal disease were observed in patients with a mean SBP of 130 mmHg to less than 140 mmHg, as compared with patients with a mean SBP of at least 140 mmHg. The additional clinical benefit of a mean SBP of less than 130 mmHg was unclear. Lower risk of all-cause death, cardiovascular mortality, and nonfatal strokes was observed in patients with a mean DBP of 80 mmHg to less than 90 mmHg. A mean DBP of less than 80 mmHg was associated with further reduction in all-cause mortality, cardiovascular mortality, ischaemic stroke, and total stroke. A mean BP of less than 140/80 mmHg was associated with further reduction in the risk of all-cause mortality, cardiovascular mortality, and nonfatal cardiovascular events in diabetic hypertensive patients.

Blood Pressure Control and Cardiovascular Outcomes: Real-world Implications of the 2017 ACC/AHA Hypertension Guideline

The 2017 American College of Cardiology/American Heart Association (ACC/AHA) hypertension guideline lowered the threshold defining hypertension and treatment target from 140/90 mmHg to 130/80 mmHg. We compared the 2017 ACC/AHA guideline and the Eighth Joint National Committee (JNC8) report with regard to the current status of hypertension using the Korean National Health and Nutrition Examination Survey. The association between blood pressure (BP) control and long-term major cardiovascular outcomes (MACEs) was analyzed using the Korea National Health Insurance Service cohort. In the cross-sectional study with 15,784 adults, the prevalence of hypertension was expected to be 49.2 ± 0.6% based on the definition suggested by the 2017 ACC/AHA guideline versus 30.4 ± 0.6% based on the JNC8 report. In a longitudinal analysis with 373,800 hypertensive adults for the median follow-up periods of 11.0 years, the adults meeting the target goal BP goal of 2017 ACC/AHA guideline were associated with 21% reduced risk of MACEs compared with adults, not meeting 2017 ACC/AHA BP goal but meeting JNC8 target goal. In conclusion, substantial increase of prevalence of hypertension is expected by the 2017 ACC/AHA guideline. This study also suggests endorsing the aggressive approach would lead to an improvement in cardiovascular care.

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

Stroke 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. This article evaluates the 'dynamic' changes of CHA2DS2-VASc variables and its effect on prediction of stroke risk. From 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. At 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, p < 0.001) or re-classified 'high-risk' groups (1.44 per 100 person-years, p = 0.048) 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. In 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.

Trends in the Prevalences of Selected Birth Defects in Korea (2008⁻2014).

Little information is available on the prevalences of birth defects in Korea. The aims of this study were to estimate recent prevalences of selected birth defects and to analyze the prevalence trends of these defects during the period from 2008 to 2014. Prevalences were calculated for 69 major birth defects using health insurance claim data obtained from the Korea National Health Insurance Service (NHIS). Prevalence rate ratios were calculated using Poisson regression to analyze trends over the 7-year study period. The overall prevalence of a major birth defect was 446.3 per 10,000 births (95% CI: 444.0–448.6); 470.9 per 10,000 births (95% CI: 467.6–474.2) for males and 420.2 per 10,000 births (95% CI: 417–423.4) for females. The prevalence rates of the most common birth defects over the study period were; septal defect (138.2 per 10,000; 95% CI: 136.9–139.5), congenital hip dislocation (652 per 10,000; 95% CI: 64.1–65.9), and ventricular septal defect (62.62 per 10,000; 95% CI: 61.7–63.5). During the study period, a significant increase in the prevalence of a major birth defect was observed with a prevalence rate ratio (PRR) of 1.091. The strongest trend was observed for renal dysplasia, which had a PRR of 1.275 (95% CI: 1.211–1.343), and upward trends were observed for urogenital anomalies, such as, renal agenesis (PRR 1.102, 95% CI: 1.067–1.138), undescended testis (PRR 1.082, 95% CI: 1.072–1.093) and hypospadias (PRR 1.067, 95% CI: 1.044–1.090). This study shows an overall increase in the prevalences of birth defects, including hypospadias and undescended testis, which are known to be associated with endocrine factors. In the future, standardized birth defect registries should be established to enable these trends to be monitored.

Development of an Algorithm for Stroke Prediction: A National Health Insurance Database Study in Korea

Background: Stroke is the second leading cause of death worldwide and remains an important health burden both for the individuals and for the national healthcare systems. Potentially modifiable risk factors for stroke include hypertension, cardiac disease, diabetes, and dysregulation of glucose metabolism, atrial fibrillation, and lifestyle factors. Objects: We aimed to derive a model equation for developing a stroke pre-diagnosis algorithm with the potentially modifiable risk factors. Methods: We used logistic regression for model derivation, together with data from the database of the Korea National Health Insurance Service (NHIS). We reviewed the NHIS records of 500,000 enrollees. For the regression analysis, data regarding 367 stroke patients were selected. The control group consisted of 500 patients followed up for 2 consecutive years and with no history of stroke. Results: We developed a logistic regression model based on information regarding several well-known modifiable risk factors. The developed model could correctly discriminate between normal subjects and stroke patients in 65% of cases. Conclusion: The model developed in the present study can be applied in the clinical setting to estimate the probability of stroke in a year and thus improve the stroke prevention strategies in high-risk patients. The approach used to develop the stroke prevention algorithm can be applied for developing similar models for the pre-diagnosis of other diseases.