Data Resource Profile: The National Health Information Database of the National Health Insurance Service in South Korea

Attention-deficit/hyperactivity disorder and subsequent diagnoses of major psychiatric disorders: a nationwide population-based study

We evaluated the risk of being diagnosed with various psychiatric disorders after an attention-deficit/hyperactivity disorder (ADHD) diagnosis using data from South Korea's National Health Insurance Service from 2002 to 2019, which covers approximately 97% of the country's population. ADHD and control groups were selected after propensity score matching was performed for individuals diagnosed with ADHD and their age- and sex-matched counterparts from the general population. Comorbid psychiatric disorders included depressive disorder, bipolar disorder, tic disorder, and schizophrenia. The incidence of newly diagnosed psychiatric disorders was compared between the groups. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated and adjusted for ADHD medication prescription. After matching, 353,898 individuals were assigned to each of the two groups. Compared to the control group, the ADHD group showed a significantly higher risk of being subsequently diagnosed with depressive disorder, bipolar disorder, schizophrenia, and tic disorder. The onset age of depressive disorder, bipolar disorder, and schizophrenia in the ADHD group was 16-17 years, approximately 5 years earlier than that in the control group. The risk for depression was the highest in individuals with high income levels, and that for schizophrenia was the highest among rural patients. The median length of the follow-up time until the diagnosis of each comorbid psychiatric disorder was 7.53, 8.43, 8.53, and 8.34 years for depressive disorder, bipolar disorder, schizophrenia, and tic disorder, respectively. Individuals with ADHD had an overall higher risk of being diagnosed with subsequent psychiatric disorders than did the controls. Hence, they should be carefully screened for other psychiatric symptoms from an early age and followed up for an extended duration, along with appropriate interventions for ADHD symptoms, including psychosocial treatments and educational approaches.

Trends in commonly used and potentially inappropriate medications in older Korean patients with polypharmacy

BACKGROUND

Polypharmacy is a global public health concern. This study aimed to determine the prevalence of polypharmacy and trends in the use of commonly used and potentially inappropriate medications among older Korean patients.

METHODS

Individuals aged ≥ 65 years who were prescribed any medication between 2014 and 2018 were selected from the Korean National Health Information Database. Joinpoint regression analyses were used to determine trends in the age-adjusted polypharmacy rates by age group. The prescription rates of the most commonly used medications and the most commonly used potentially inappropriate medications were analysed by year or age group for patients with polypharmacy using the chi-square and proportion difference tests.

RESULTS

This study included 1,849,968 patients, 661,206 (35.7%) of whom had polypharmacy. Age-adjusted polypharmacy rates increased significantly between 2014 and 2018 (P = 0.046). Among patients with polypharmacy, the most commonly prescribed medications were aspirin (100 mg), atorvastatin, metformin, glimepiride, and rosuvastatin. The most commonly prescribed and potentially inappropriate medications were alprazolam, diazepam, amitriptyline, zolpidem, and dimenhydrinate. There was a significant decrease in the prescription rates for each of these drugs in 2018 compared with 2014 among patients with polypharmacy (all P < 0.001), whereas there was a significant increase in alprazolam prescription among patients aged ≥ 85 years when analysed by age group (P < 0.001).

CONCLUSIONS

This study revealed an increasing prevalence of polypharmacy among older adults. Additionally, it highlighted that the utilisation of commonly prescribed potentially inappropriate medications, such as benzodiazepines and tricyclic antidepressants, has remained persistent, particularly among patients aged ≥ 85 years who practiced polypharmacy. These findings provide evidence-based guidance for the development of robust polypharmacy management strategies to ensure medication safety among older adults.

National trend in the prevalence and mortality of COPD in South Korea from 2008 to 2017

BACKGROUND

Existing studies on chronic obstructive pulmonary disease (COPD) in Korea lack full population coverage, relying on small sample sizes. Therefore, this study aims to investigate the prevalence and mortality of COPD in the entire Korean population.

METHODS

This serial cross-sectional study used national databases, linking the National Health Information Database (2008-2017) with Causes of Death Statistics. Identification of individuals with COPD used diagnostic codes (International Classification of Diseases-10: J41-J44) or a history of COPD-related hospitalisation, focusing on adults aged 40 and above. Prevalence and mortality rates, calculated for 2008-2017, encompassed both crude and age-standardised and sex-standardised measures. A multivariate Poisson regression model estimated the association between COPD and all-cause and cause-specific mortality, presenting incidence rate ratios (IRRs) and 95% CIs, using data from the year 2017.

RESULTS

Age-adjusted COPD prevalence exhibited a notable increase from 2008 (7.9%) to 2017 (16.7%) in both sexes. The prevalences of diabetes mellitus, hypertension, dyslipidaemia, ischaemic heart disease, cancer, osteoporosis and tuberculosis were higher in the COPD group than in the group without COPD (p for all <0.001). The incidence of stroke and myocardial infarction (p for all <0.001) and overall mortality were higher in the COPD group (adjusted IRR 1.23, 95% CI 1.22 to 1.24, p<0.001). In particular, incidence rate and risk of mortality due to lung cancer were higher than that of those without COPD compared with other cancer types (adjusted IRR 2.51, 95% CI 2.42 to 2.60, p<0.001). It was significantly higher the incidence rate and risk of mortality among group with COPD than those without COPD in lower respiratory disease (adjusted IRR 16.62, 95% CI 15.07 to 18.33, p<0.001), asthma (adjusted IRR 6.41, 95% CI 5.47 to 7.51, p<0.001) and bronchiectasis (adjusted IRR 11.77, 95% CI 7.59 to 18.26, p<0.001), respectively.

DISCUSSION

Our study showed that the prevalence of COPD is gradually increasing from 9.2% in 2009 to 16.7% in 2018. Furthermore, in overall (all-cause) mortality, it was significantly higher in group with COPD than in group without COPD. The mortality rate of group with COPD was much higher than the overall mortality rate but is gradually decreasing.

The influence of factors associated with past reproductive histories on migraines in middle-aged premenopausal women: a nationwide population-based study in Republic of Korea

Introduction

Women can experience various reproductive events, such as pregnancy, childbirth, lactation, and contraception, which cause long-term changes in female hormones. In middle-aged women, the prevalence of migraine is high, and a clear gender difference is evident. This study investigated the effects of factors associated with past reproductive events on the risk of new migraine in middle-aged premenopausal women.

Methods

The influence of reproductive factors on migraine in middle-aged women was investigated using the Korean National Health Insurance Service (KNHIS) and Korean Health Examination (KHE) databases. The reproductive factors of interest were parity, breastfeeding, and oral contraceptive (OC) use. The study included 949,704 middle-aged premenopausal women 40-60 years of age. The study population was divided into two groups based on new diagnosis of migraine during the follow-up period (2009-2018).

Results

The risk of new migraine tended to increase in the primiparous (hazard ratio, HR: 1.179; 95% confidence interval, CI: 1.137-1.221) and multiparous groups (HR: 1.181; 95% CI: 1.142-1.221) compared with the nulliparous group. The breastfeeding ≥12 months group (HR: 1.071; 95% CI: 1.052-1.091) showed a significantly increased risk of new migraine compared with the non-breastfeeding group. All women in the OC groups (< 1 year, HR: 1.048; 95% CI: 1.028-1.069 and ≥ 1 year, HR: 1.100; 95% CI: 1.067-1.134) showed a higher risk of new migraine than those in the non-OC group.

Conclusion

The results of the current study indicate that childbirth, longer breastfeeding, and OC use may be associated with a higher risk of new migraine in middle-aged premenopausal women.

Association between changes in renal function and clinical outcomes in anticoagulated atrial fibrillation patients with marginal renal function. A nationwide observational cohort study

Background

Renal function is one of the crucial components for determining the dose and type of oral anticoagulants in atrial fibrillation (AF) patients, and is also closely associated with the risks of stroke and bleeding. This study aimed to assess renal function changes and their impact on clinical outcomes in anticoagulated AF patients with marginal renal function.

Methods

From a Korean claims database, patients with AF on anticoagulants and a baseline eGFR of 45 to <60 ml/min/1.73 m2 were studied. Patients were grouped by changes in renal function over two years-maintained, improved (eGFR >60 ml/min/1.73 m2), or worsened (eGFR <45 ml/min/1.73 m2)-the study analyzed outcomes including ischemic stroke, major bleeding, end-stage renal disease (ESRD), all-cause death, and a composite of clinical outcomes.

Results

A total of 5,126 patients were included in the study: 2,170 (42.3%) in the maintained group, 2,276 (44.4%) in the improved group, and 680 (13.1%) in the group with worsened renal function. The worsened group was older and had more prevalent comorbidities than other groups. After multivariable adjustment, the worsened group was associated with significantly higher risks of major bleeding (adjusted hazard ratio, 95% confidence interval; 1.46, 1.03-2.07, p = 0.035), ESRD (1.49, 1.24-1.80, p < 0.001), all-cause death (9.29, 4.92-17.6, p < 0.001), and the composite outcome (1.57, 1.36-1.83, p < 0.001).

Conclusions

In anticoagulated AF patients with marginal renal function, a substantial proportion of patients experienced renal function decline below eGFR 45 ml/min/1.73 m2 within 2 years. Renal function decline was associated with higher risks of major bleeding, ESRD, all-cause death, and the composite outcome compared to those who maintained their baseline renal function.

Association Between COPD and Hearing Loss

OBJECTIVE

The goal of the present study was to estimate the risk of hearing impairment in patients with COPD using huge nationwide population.

METHODS

A retrospective case-control study was performed using the National Health Insurance Database in South Korea from 2002 through 2019. Totally 614,370 COPD patients and matched 2,170,504 control participants were selected at a 1:4 ratio. Hearing impairment was defined based on the registered data in the Ministry of Health and Welfare of Korea with six levels of severity of hearing impairment. The propensity score was calculated, and overlap-weighted multinomial logistic regression was used to calculate the odds ratios of COPD for hearing impairment.

RESULTS

A total of 2.67% of COPD patients and 1.9% of control participants had hearing impairment. The COPD patients indicated 1.10-1.21 times higher odds for hearing impairment according to the severity of hearing impairment than the control group. In accordance with age and sex, the younger age group (<65 years old) and female group demonstrated higher odds for hearing impairment related to the presence of COPD. The high odds for hearing impairment in patients with COPD was consistent in all other subgroups, except for the underweight group.

CONCLUSIONS

COPD was associated with an increased risk of hearing impairment in the general population in Korea.

LEVEL OF EVIDENCE

3 Laryngoscope, 2024.

The Relation Between Cigarette Smoking and Development of Sepsis: A 10-Year Follow-Up Study of Four Million Adults from the National Health Screening Program

BACKGROUND

Sepsis remains a growing global health concern with soaring mortality and no direct anti-sepsis drug. Although smoking has distinct deleterious effects on chronic inflammatory illnesses and can impair immune function, a comprehensive analysis of the connection between sepsis and smoking is lacking.

METHODS

This large-scale longitudinal cohort study retrospectively assessed adults aged ≥ 20 years who underwent national health checkups under the Korean National Health Insurance Service between January and December 2009 (N = 4,234,415) and were followed up for 10 years. Sepsis was identified based on the International Classification of Diseases, 10th Revision codes, and smoking status, including accumulated amount, was collected through a self-administered questionnaire. The Cox proportional hazard regression model was used, adjusting for age, sex, household income, body mass index, drinking, exercise, diabetes, hypertension, dyslipidemia, and chronic renal disease.

RESULTS

After excluding cases with sepsis occurring before follow-up or after ≤ 1 year of follow-up, 3,881,958 participants, including non-smokers (N = 2,342,841), former smokers (N = 539,850), and active smokers (N = 999,267), were included. Compared to non-smokers, all active smokers (adjust hazard ratio: 1.41, 95% confidence interval 1.38-1.44) and former smokers (1.10, 1.07-1.14) with ≥ 20 pack-years exhibited a significantly higher risk of sepsis (p < 0.001). Smoking of ≥ 30 pack-years in former and active smokers groups significantly increased sepsis incidence (adjust hazard ratio [95% confidence interval] 1.34 [1.31-1.38], p < 0.001).

CONCLUSIONS

Smoking is closely associated with the incidence of sepsis. Smoking cessation may help in the primary prevention of sepsis.

Fracture Risk Among Stroke Survivors According to Poststroke Disability Status and Stroke Type

BACKGROUND

Stroke survivors face physical and cognitive challenges, leading to an increased dependency and a higher fall risk. We aimed to investigate the impact of poststroke disability and stroke type on fracture risk at various sites compared with matched controls.

METHODS

This retrospective cohort study used data from the Korean National Health Insurance System database (2010-2018), including patients with stroke and 1:1 matched controls. Stroke survivors were grouped based on the presence and severity of their poststroke disability and stroke type. The primary outcome was a newly diagnosed fracture, analyzed by Cox proportional hazard regression analyses adjusting for potential confounders.

RESULTS

Among 223 358 stroke survivors (mean age, 64.8±10.9 years; 61.2% men), 16 344 fractures occurred during a mean follow-up of 3.7±2.5 years. In matched controls (n=322 161; mean age, 65.4±11.2 years; 61.3% men), 20 398 fractures were identified. Stroke survivors had increased overall fracture risk compared with matched controls (adjusted hazard ratio [aHR], 1.40 [95% CI, 1.37-1.43]). Specifically, hip fracture risk was even greater in stroke survivors (incidence rate per 1000 person-years, 4.7 [95% CI, 4.5-4.8]; aHR, 2.42 [95% CI, 2.30-2.55]) than controls (incidence rate, 2.2 [95% CI, 2.1-2.3]). The risk of vertebral fractures (aHR, 1.29 [95% CI, 1.25-1.34]) and other fractures (aHR, 1.19 [95% CI, 1.15-1.23]) was also higher than that of the control group. Hip fracture risk was the highest among stroke survivors with severe poststroke disability (aHR, 4.82 [95% CI, 4.28-5.42]), although vertebral or other fracture risk was the highest among those with mild poststroke disability. No significant difference in fracture risk was found between hemorrhagic and ischemic stroke survivors when stratified by disability status.

CONCLUSIONS

Our findings showed increased subsequent fracture risk among stroke survivors, particularly those with poststroke disability and for hip fracture. Bone health assessment and treatment should be emphasized as an essential part of stroke management.

Association of obstructive sleep apnea with risk of lung cancer: a nationwide cohort study in Korea

Current knowledge regarding the relationship between obstructive sleep apnea (OSA) and the risk of lung cancer is limited. This study aimed to evaluate associations between OSA and the incidence of lung cancer based on the Korean National Health Information Database. The study outcome was the incidence of newly diagnosed lung cancer, and a Cox proportional hazards model was used for analysis. A total of 181,070 adult patients newly diagnosed with OSA between 2011 and 2018 were matched with those without OSA by up to 1:5 propensity score matching based on age and sex. During follow-up over (mean ± standard deviation) 9.1 ± 2.0 years, 2614 incident cases of lung cancer were identified. The incidence rate was 39.51 per 100,000 person-years in the OSA group, and 24.93 per 100,000 person-years in the control group. After adjusting for income and the presence of comorbidities, the association remained significant (hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.74-2.18, p-value < 0.001). The adjusted HR for incident lung cancer was 2.14 (95% CI 1.69-2.70) in female patients with OSA, and 1.90 (95% CI 1.67-2.16) in male patients with OSA. The risk of incident lung cancer increased with age, with a HR of 2.99 (95% CI 2.46-3.64) in those aged ≥ 65 years. This nationwide study showed an independent association between OSA and an increased risk of lung cancer in the Korean population.

Association between exposure to antibiotics during pregnancy or early infancy and risk of autism spectrum disorder, intellectual disorder, language disorder, and epilepsy in children: population based cohort study

OBJECTIVE

To evaluate the association between antibiotic use during pregnancy or early infancy and the risk of neurodevelopmental disorders in children.

DESIGN

Nationwide population based cohort study and sibling analysis.

SETTING

Korea's National Health Insurance Service mother-child linked database, 2008-21.

PARTICIPANTS

All children live born between 2009 and 2020, followed up until 2021 to compare those with and without antibiotic exposure during pregnancy or early infancy (first six months of life).

MAIN OUTCOMES MEASURES

Autism spectrum disorder, intellectual disorder, language disorder, and epilepsy in children. After 1:1 propensity score matching based on many potential confounders, hazard ratios with 95% confidence interval were estimated using Cox proportional hazard models. A sibling analysis additionally accounted for unmeasured familial factors.

RESULTS

After propensity score matching, 1 961 744 children were identified for the pregnancy analysis and 1 609 774 children were identified for the early infancy analysis. Although antibiotic exposure during pregnancy was associated with increased risks of all four neurodevelopmental disorders in the overall cohort, these estimates were attenuated towards the null in the sibling analyses (hazard ratio for autism spectrum disorder 1.06, 95% confidence interval 1.01 to 1.12; intellectual disorder 1.00, 0.93 to 1.07; language disorder 1.05, 1.02 to 1.09; and epilepsy 1.03, 0.98 to 1.08). Likewise, no association was observed between antibiotic exposure during early infancy and autism spectrum disorder (hazard ratio 1.00, 0.96 to 1.03), intellectual disorder (1.07, 0.98 to 1.15), and language disorder (1.04, 1.00 to 1.08) in the sibling analyses; however, a small increased risk of epilepsy was observed (1.13, 1.09 to 1.18). The results generally remained consistent across several subgroup and sensitivity analyses, except for slightly elevated risks observed among children who used antibiotics during very early life and those who used antibiotics for more than 15 days.

CONCLUSIONS

In this large cohort study, antibiotic exposure during pregnancy or early infancy was not associated with an increased risk of autism spectrum disorder, intellectual disorder, or language disorder in children. However, elevated risks were observed in several subgroups such as children using antibiotics during very early life and those with long term antibiotic use, which warrants attention and further investigation. Moreover, antibiotic use during infancy was modestly associated with epilepsy, even after control for indications and familial factors. When prescribing antibiotics to pregnant women and infants, clinicians should carefully balance the benefits of use against potential risks.

The risk of open angle glaucoma in young adults with allergic diseases: a Nationwide cohort study

This study investigated the potential associations between allergic diseases (asthma, allergic rhinitis, and atopic dermatitis) and the development of primary open-angle glaucoma. We utilized authorized data from the Korean National Health Information Database (KNHID), which provides comprehensive medical claims data and information from the National Health Screening Program. We compared the baseline characteristics of subjects with and without allergic diseases and calculated the incidence and risk of glaucoma development. Cox proportional hazard regression analysis was used to determine the risk of glaucoma development in subjects with allergic diseases. A total of 171,129 subjects aged 20-39 with or without allergic diseases who underwent a general health examination between 2009 and 2015 were included. Subjects with allergic diseases exhibited a higher incidence of glaucoma compared to the control group. The hazard ratio (HR) of glaucoma onset was 1.49 and 1.39 in subjects with at least one allergic disease before and after adjusting for potential confounding factors, respectively. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development (aHR 1.73) after adjusting for confounders. Allergic rhinitis showed an increased risk for incident glaucoma after adjustment (aHR 1.38). Asthma showed the lowest but still increased risk for glaucoma (aHR 1.22). The associations were consistent in all subgroup analyses stratified by sex, smoking, drinking, exercise, diabetes, hypertension, dyslipidemia, or history of steroid. In conclusion, allergic diseases are associated with increased risk of glaucoma development. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development followed by allergic rhinitis and asthma.

Association between types of antihypertensive medication and the risk of atrial fibrillation: a nationwide population study

Background

Patients with hypertension are at a high risk of atrial fibrillation (AF). Recent research has indicated the varying effects of antihypertensive medications on developing AF.

Objectives

We investigated the relationship between different types of antihypertensive medications and the risk of AF occurrence.

Methods

We analyzed data from 113,582 subjects with national health screening examinations between 2009 and 2014. The study population was categorized according to antihypertensive medication type. The primary outcome was the incidence of AF.

Results

Among 113,582 subjects (mean age 59.4 ± 12.0 years, 46.7% men), 93,557 received monotherapy [angiotensin receptor blockers (ARB), angiotensin-converting enzyme inhibitors (ACEi), beta-blockers, calcium channel blockers (CCB), or diuretics], while 34,590 received combination therapy (ARB/beta-blockers, ARB/CCB, ARB/diuretics, or ARB/CCB/diuretics). During a mean follow-up duration of 7.6 ± 2.1 years, 3.9% of patients were newly diagnosed with AF. In monotherapy, ACEi and CCB had similar AF risks as ARB, while beta-blockers and diuretics showed higher AF risks than ARB. In combination therapy, ARBs/CCBs and ARBs/diuretics had the lowest AF risk, whereas ARBs/beta-blockers had the highest compared to ARB/CCB. Among the specific ARBs, the AF risk varied insignificantly, except for telmisartan and candesartan.

Conclusions

In hypertensive patients receiving monotherapy, ACEi and CCB showed a similar AF risk as ARBs, while beta-blockers and diuretics were associated with a higher risk. Among those receiving combination therapy, ARBs/CCBs and ARBs/diuretics had the lowest AF risk, whereas ARBs/beta-blockers showed the highest risk. Various types of ARBs have different associations with AF risk.

Cancer Risk in Graves Disease with Radioactive 131I Treatment: A Nationwide Cohort Study

Radioactive 131I (RAI) therapy has potential effects for the treatment of Graves disease (GD). However, whether RAI therapy for GD increases cancer risk remains controversial in medicine and public health. We aimed to investigate whether the risk of cancer increases in patients with GD receiving RAI therapy compared with those who did not. Methods: We used the Korean National Health Insurance Service's National Health Information Database from 2004 to 2020 and defined GD as prescribing antithyroid drugs, RAI, or thyroidectomy as a treatment for GD (International Classification of Diseases, 10th revision, E05 group). We investigated the hazard ratios (HRs) of overall and site-specific cancers associated with RAI in patients with GD. Subsequent cancer was defined as a primary malignancy treated at least 1 y after RAI therapy. Results: In total, 10,737 patients with GD who received RAI therapy (7,193 women, 67.0%; mean age, 43.7 ± 13.4 y) were matched to 53,003 patients with GD who had never received RAI treatment (35,471 women, 66.9%; mean age, 43.8 ± 13.2 y) in a 1:4-5 ratio by age, sex, and health checkup data. The median follow-up duration was 8.7 y (interquartile range, 5.2-12.1 y), and the median cumulative RAI dose was 555 MBq (interquartile range, 370-630 MBq) in the RAI therapy group. During 2004-2020, the overall subsequent cancer rates were 5.66 and 5.84 per 1,000 person-years in the RAI and non-RAI groups, respectively, with an unadjusted HR of 0.97 (95% CI, 0.88-1.06); this remained at 0.96 (95% CI, 0.83-1.10) after adjustment for multiple clinical confounding factors. For cancer subtypes, the risk of leukemia was significantly increased, with an HR of 2.39 (95% CI, 1.17-4.91). However, a loss of statistical significance was observed after adjusting for confounding factors, which may be attributed to the limited number of absolute events. Moreover, cancer-specific mortality was not different between the RAI and the non-RAI groups, with an adjusted HR of 0.99 (95% CI, 0.66-1.47). Conclusion: This study identified that the overall cancer risk in patients with GD who received RAI therapy compared with those who did not was not significant in Korea. Further long-term studies are needed to determine the risks and advantages of RAI therapy in patients with GD.

Epidemiology of autoimmune liver disease in Korea: evidence from a nationwide real-world database

BACKGROUND

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are all immune-mediated chronic inflammatory liver diseases. Autoimmune liver diseases are rare, making identification and treatment difficult. To improve clinical outcomes and enhance patient quality of life, we performed an epidemiological study of autoimmune liver diseases based on real-world comprehensive data.

RESULTS

We used National Health Insurance Service claims data in Korea from 2005 to 2019. Patients were identified using the International Classification of Disease 10th Revision code, and rare intractable disease codes assigned according to the strict diagnostic criteria. In the AIH cohort, 8,572 (83.9%) were females and the mean age at diagnosis was 56.3 ± 14.3 years. PBC also showed female dominance (83.3%) and the mean age was 57.8 ± 12.6 years. Patients with PSC showed no sex predominance and had a mean age of 57.8 ± 21.5 years. During the study period, there were 10,212, 6,784, and 888 AIH, PBC, and PSC patients, respectively. The prevalence of AIH, PBC, and PSC in 2019 were 18.4, 11.8, and 1.5 per 100,000 population, while the corresponding incidences were 2.3, 1.4, and 0.3 per 100,000 population, respectively. Analysis of sex-age-standardized data showed that the annual prevalence of these diseases is increasing. The 10-year survival rates were 89.8%, 74.9%, and 73.4% for AIH, PBC, and PSC, respectively.

CONCLUSIONS

The number of patients with autoimmune liver disease in South Korea is increasing over time. Further research on autoimmune liver disease is needed to fulfill unmet clinical needs.

Association of midlife body-weight variability and cycles with earlier dementia onset: a nationwide cohort study

BACKGROUND

Given the rising awareness of health-related lifestyle modifications, the impact of changes in body weight (BW) on cognitive function and dementia generates significant concern. This study aimed to investigate the association between BW changes and dementia in a middle-aged Korean population.

METHODS

A retrospective, population-based longitudinal study was conducted utilizing data from the National Health Insurance Service (NHIS) database. Participants aged 40 years or older in 2011 who underwent at least five health checkups between 2002 and 2011 were followed-up for dementia until 2020. A total of 3,635,988 dementia-free Korean aged < 65 at baseline were examined. We analyzed the association between BW variability independent of the mean (VIM) with BW cycle, defined as either an upward or a downward direction of BW, and the risk of incident dementia.

RESULTS

The results showed an increased risk of dementia in the highest quartile of VIM quartile (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.47-1.58) compared to the lowest quartile of VIM. Additionally, the results showed an even higher increased risk of dementia in the highest BW cycle (≥ 2 cycles of 10% BW = HR 2.00, 95% CI 1.74-1.29). Notably, the combined concept of VIM with BW cycle showed an even higher dementia risk (highest quartile of VIM with ≥ 2 cycles of 10% BW = HR 2.37, 95% CI 2.05-2.74) compared to the baseline group (lowest quartile of VIM with < 3% BW cycle).

CONCLUSIONS

The present study highlights the importance of considering BW changes with BW variability along with the BW cycle to assess dementia risk in detail, providing valuable insights for preventive strategies.

Changes in physical activity and diabetes risk after cancer diagnosis: a nationwide cohort study

PURPOSE

Physical activity has the potential to reduce the risk of diabetes after cancer diagnosis. However, current evidence supporting its effects is limited. This study aims to examine the associations between changes in physical activity and subsequent risk of diabetes among cancer survivors.

METHODS

A total of 264,250 cancer survivors (mean age 56.7 (12.5) years, 44.2% males) without a prior history of diabetes were assessed for adherence to physical activity both before and after their diagnosis. The primary outcome was incident diabetes. The Fine-Gray proportional sub-distribution hazards model was used to calculate sub-distribution hazard ratios (sHRs) and 95% confidence intervals (CIs) for diabetes risk, considering death as a competing risk.

RESULTS

Over a follow-up of 1,065,802 person-years, maintaining regular physical activity from pre-diagnosis was associated with a 10% reduced risk of diabetes after cancer diagnosis (sHR 0.90, 95% CI 0.85-0.96), considering traditional diabetes risk factors, sociodemographics, and primary cancer sites. Cancer survivors who became active and inactive after their cancer diagnosis exhibited a marginally decreased risk of diabetes (sHR 0.98, 95% CI 0.93-1.03; sHR 0.97, 95% CI 0.92-1.03). The strength and direction of the association varied depending on the primary site of cancer.

CONCLUSIONS

Regular physical activity starting before a cancer diagnosis is associated with a lower risk of diabetes following the diagnosis, independent of established diabetes risk factors.

IMPLICATIONS FOR CANCER SURVIVORS

The study underscores the importance of engaging in sufficient physical activity to mitigate the risk of diabetes in cancer survivors.

An Ensemble Feature Selection Approach-Based Machine Learning Classifiers for Prediction of COVID-19 Disease

The respiratory disease of coronavirus disease 2019 (COVID-19) has wreaked havoc on the economy of every nation by infecting and killing millions of people. This deadly disease has taken a toll on the life of the entire human race, and an exact cure for it is still not developed. Thus, the control and cure of this disease mainly depend on restricting its transmission rate through early detection. The detection of coronavirus infection facilitates the isolation and exclusive care of infected patients. This research paper proposes a novel data mining system that combines the ensemble feature selection method and machine learning classifier for the effective identification of COVID-19 infection. Different feature selection approaches including chi-square test, recursive feature elimination (RFE), genetic algorithm (GA), particle swarm optimization (PSO), and random forest are evaluated for their effectiveness in enhancing the classification accuracy of the machine learning classifiers. The classifiers that are considered in this research work are decision tree, naïve Bayes, K-nearest neighbor (KNN), multilayer perceptron (MLP), and support vector machine (SVM). Two COVID-19 datasets were used for testing from which the best features supporting the dataset were extracted by the proposed system. The performance of the machine learning classifiers based on the ensemble feature selection methods is analyzed.

Association between statin use and the risk for idiopathic pulmonary fibrosis and its prognosis: a nationwide, population-based study

Given the pleiotropic effects of statins beyond their lipid-lowering effects, there have been attempts to evaluate the role of statin therapy in IPF, but they have shown inconclusive results. Data from the National Health Insurance Service (NHIS) database of South Korea were used to investigate the effects of statin therapy on IPF. The IPF cohort consisted of a total of 10,568 patients who were newly diagnosed with IPF between 2010 and 2017. These patients were then matched in a 1:3 ratio to 31,704 subjects from a control cohort without IPF, with matching based on age and sex. A case-control study was performed to evaluate the association between statin use and the risk for IPF, and the multivariable analysis revealed that statin use was associated with a lower risk for IPF (adjusted OR 0.847, 95% CI 0.800-0.898). Using the IPF cohort, we also evaluated whether statin use at the time of diagnosis was associated with future clinical outcomes. The statin use at the time of IPF diagnosis was associated with improved overall survival (adjusted HR 0.779, 95% CI 0.709-0.856). Further prospective studies are needed to clarify the role of statin therapy in IPF.

Heart Failure Statistics 2024 Update: A Report From the Korean Society of Heart Failure

Background and Objectives

The number of people with heart failure (HF) is increasing worldwide, and the social burden is increasing as HF has high mortality and morbidity. We aimed to provide updated trends on the epidemiology of HF in Korea to shape future social measures against HF.

Methods

We used the National Health Information Database of the National Health Insurance Service to determine the prevalence, incidence, hospitalization rate, mortality rate, comorbidities, in-hospital mortality, and healthcare cost of patients with HF from 2002 to 2020 in Korea.

Results

The prevalence of HF in the total Korean population rose from 0.77% in 2002 to 2.58% (1,326,886 people) in 2020. Although the age-standardized incidence of HF decreased over the past 18 years, the age-standardized prevalence increased. In 2020, the hospitalization rate for any cause in patients with HF was 1,166 per 100,000 persons, with a steady increase from 2002. In 2002, the HF mortality was 3.0 per 100,000 persons, which rose to 15.6 per 100,000 persons in 2020. While hospitalization rates and in-hospital mortality for patients with HF increased, the mortality rate for patients with HF did not (5.8% in 2020), and the one-year survival rate from the first diagnosis of HF improved. The total healthcare costs for patients with HF were approximately $2.4 billion in 2020, a 16-fold increase over the $0.15 billion in 2002.

Conclusions

The study's results underscore the growing socioeconomic burden of HF in Korea, driven by an aging population and increasing HF prevalence.

Glycemic control and dementia risk in patients aged above and below 75 years

Background

There is a lack of data about the treatment effect of glycemic control on incident dementia in patients with advanced age.

Methods

In a nationwide Korean cohort of 79,076 diabetic patients 75 years or older and a representative cohort of 74,672 diabetics aged 50 to 74 years, multivariable-adjusted incidence of overt dementia was estimated across yearly-averaged on-treatment fasting blood glucose (FBG) levels.

Results

During 9-year follow-up, overt dementia was noted in 24,710 (31.2%) patients 75 years or older and in 5237 (7.0%) patients aged 50 to 74 years. For dementia risk, J-shaped associations were observed across on-treatment FBG levels (80-99, 100-109, 110-125, 126-139, 140-159, 160-179, and 180-900 mg/dl) in patients 75 years or older (respective incidence: 49.3, 45.7, 45.9, 45.7, 48.5, 51.5, and 57.9 per 1000 person-years) and in those aged 50 to 74 years (respective incidence: 8.9, 8.3, 7.7, 7.6, 8.0, 8.6, and 10.6 per 1000 person-years) with a significant interaction of FBG level and age group (P = 0.001). For all-cause mortality, the J-shaped association curve was left-shifted in patients 75 years or older (respective incidence: 64.9, 59.1, 57.6, 60.4, 64.0, 70.9, and 90.4 per 1000 person-years) relative to that in patients aged 50 to 74 years (respective incidence: 15.7, 13.4, 12.3, 12.2, 13.4, 15.7, and 21.8 per 1000 person-years; P < 0.001 for interaction).

Conclusion

The achieved glycemic level with the lowest risk for dementia and mortality was lower in older patients, and absolute risk increase related to poorly controlled glucose was greater in the elderly compared with younger patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-023-00684-4.

The impact of preoperative coronavirus disease 19 infection on early postoperative mortality during the vaccination era: a nationwide retrospective cohort study

BACKGROUND

We aimed to investigate the optimal surgical timing in patients with preoperative coronavirus disease 2019 (COVID-19) infection to minimize postoperative morbidity and mortality during the COVID-19 vaccination era.

METHODS

The Korean nationwide data on patients who underwent standard surgery under general anesthesia in 2021 were analyzed. Patients were categorized based on the time from COVID-19 diagnosis to surgery: 0-4, 5-8, > 8 weeks, and those without preoperative COVID-19 infection. Multivariable logistic regression analysis, considering preoperative COVID-19 vaccination status (fully vaccinated vs. unvaccinated or partially vaccinated), was performed to associate the preoperative COVID-19 infection timing with 30- and 90-day postoperative mortality and 30-day respiratory complications.

RESULTS

Among the 750,175 included patients, 28.2% were preoperatively fully vaccinated. Compared with patients without prior COVID-19 infection, those who had surgery 0-4 weeks (adjusted odds ratio [OR]: 4.28, 95% CI [1.81, 10.13], P = 0.001) and 5-8 weeks (adjusted OR: 3.38, 95% CI [1.54, 7.44], P = 0.002) after COVID-19 infection had a significantly increased risk of 30-day mortality. Preoperative full vaccination was significantly associated with a decrease in 90-day mortality (adjusted OR: 0.93, 95% CI [0.89, 0.98], P = 0.007) and 30-day respiratory complications (adjusted OR: 0.85, 95% CI [0.82, 0.87], P < 0.001), but not with 30-day mortality (P = 0.916).

CONCLUSIONS

COVID-19 infection eight weeks preoperatively was associated with an increased 30-day postoperative mortality. Preoperative full vaccination was not associated with 30-day mortality but was related to lower risk of 90-day mortality and 30-day respiratory complications.

2023 Obesity Fact Sheet: Prevalence of Obesity and Abdominal Obesity in Adults, Adolescents, and Children in Korea from 2012 to 2021

Background

The 2023 Obesity Fact Sheet aims to present an updated overview of obesity prevalence across all age groups, including children and adolescents.

Methods

This study included individuals aged ≥20 years (n=16,941,423 in 2021) who underwent health checkups provided by the Korean National Health Insurance Service between 2012 and 2021. The prevalence of obesity and abdominal obesity was standardized by age and sex using data from the 2010 population and housing census. For children and adolescents (6 to 18 years) (n=884 in 2021), we used the Korea National Health and Nutrition Examination Survey (2012 to 2021), and obesity was defined by the corresponding sex- and age-specific body mass index percentile of 95th or greater based on the 2017 Korean National Growth Chart for Children and Adolescents.

Results

The overall prevalence of obesity in 2021 is 38.4% (49.2% in men and 27.8% in women), which is a 1.27-fold increase from 30.2% in 2012. The prevalence of obesity has increased across all age groups, particularly among those aged 20, 30, and 80 years. The prevalence of class III obesity substantially increased from 0.35% (men) and 0.42% (women) in 2012 to 1.21% and 0.97% in 2021, with 3.46- and 2.31-fold increases, respectively. This increase was particularly pronounced in young adults. The prevalence of obesity in children and adolescents has surged from 9.7% in 2012 to 19.3% in 2021, with a greater increase among boys.

Conclusion

Our study provides information on the current status of obesity prevalence based on the 2023 Obesity Fact Sheet, emphasizing the urgency of implementing timely strategies to reverse this increasing trend.

Effect of physical activity on incident atrial fibrillation in individuals with varying duration of diabetes: a nationwide population study

BACKGROUND

Diabetes mellitus (DM) duration affects incident atrial fibrillation (AF) risk; the effect of physical activity on mitigating AF risk related to varying DM duration remains unknown. We assessed the effect of physical activity on incident AF in patients with DM with respect to known DM duration.

METHODS

Patients with type 2 DM who underwent the Korean National Health Insurance Service health examination in 2015-2016 were grouped by DM duration: new onset and < 5, 5-9, and ≥ 10 years. Physical activity was classified into four levels: 0, < 500, 500-999, 1,000-1,499, and ≥ 1,500 metabolic equivalent task (MET)-min/week, with the primary outcome being new-onset AF.

RESULTS

The study enrolled 2,392,486 patients (aged 59.3 ± 12.0 years, 39.8% female) with an average follow-up of 3.9 ± 0.8 years and mean DM duration of 5.3 ± 5.1 years. Greater physical activity was associated with a lower AF risk. Lowering of incident AF risk varied with different amounts of physical activity in relation to known DM duration. Among patients with new-onset DM, DM duration < 5 years and 5-9 years and 1,000-1,499 MET-min/week exhibited the lowest AF risk. Physical activity ≥ 1,500 MET-min/week was associated with the lowest incident AF risk in patients with DM duration ≥ 10 years (by 15%), followed DM duration of 5-9 years (12%) and < 5 years (9%) (p-for-interaction = 0.002).

CONCLUSIONS

Longer DM duration was associated with a high risk of incident AF, while increased physical activity generally reduced AF risk. Engaging in > 1,500 MET-min/week was associated with the greatest AF risk reduction in patients with longer DM duration, highlighting the potential benefits of higher activity levels for AF prevention.

Longitudinal BMI change and outcomes in Chronic Obstructive Pulmonary Disease: a nationwide population-based cohort study

BACKGROUND

The association between longitudinal body mass index (BMI) change and clinical outcomes in patients with chronic obstructive pulmonary disease (COPD) has not fully investigated.

METHODS

This retrospective cohort study included 116,463 COPD patients aged ≥ 40, with at least two health examinations, one within 2 years before and another within 3 years after COPD diagnosis (January 1, 2014, to December 31, 2019). Associations between BMI percentage change with all-cause mortality, primary endpoint, and initial severe exacerbation were assessed.

RESULTS

BMI decreased > 5% in 14,728 (12.6%), while maintained in 80,689 (69.2%), and increased > 5% in 21,046 (18.1%) after COPD diagnosis. Compared to maintenance group, adjusted hazard ratio (aHR) for all-cause mortality was 1.70 in BMI decrease group (95% CI:1.61, 1.79) and 1.13 in BMI increase group (95% CI:1.07, 1.20). In subgroup analysis, decrease in BMI showed a stronger effect on mortality as baseline BMI was lower, while an increase in BMI was related to an increase in mortality only in obese COPD patients with aHRs of 1.18 (95% CI: 1.03, 1.36). The aHRs for the risk of severe exacerbation (BMI decrease group and increase group vs. maintenance group) were 1.30 (95% CI:1.24, 1.35) and 1.12 (95% CI:1.07, 1.16), respectively.

CONCLUSIONS

A decrease in BMI was associated with an increased risk of all-cause mortality in a dose-dependent manner in patients with COPD. This was most significant in underweight patients. Regular monitoring for weight loss might be an important component for COPD management.

Association of the Intensive Blood Pressure Target and Cardiovascular Outcomes in the Population With Chronic Kidney Disease: A Retrospective Study in Korea

BACKGROUND

Recently, the target systolic blood pressure (BP) <120 mm Hg was suggested in the population with chronic kidney disease. We aimed to determine the applicability of intensified BP and to assess the incidence of cardiovascular disease (CVD) in the population with chronic kidney disease.

METHODS AND RESULTS

Participants who were >20 years old and had estimated glomerular filtration rate 15 to 60 mL/min per 1.73 m2 during 2009 to 2011 were included from the database of Korean National Health Insurance Service and were followed up to 2018. Participants were categorized by BP as <120/80 mm Hg; 120 to 129/<80 mm Hg; 130 to 139/80 to 89 mm Hg; ≥140/90 mm Hg. The primary outcome was CVD risk and the secondary outcomes were all-cause mortality and progression to end-stage renal disease followed by subgroup analysis. Among the 45 263 adults with chronic kidney disease, 5196 CVD events were noted. In Cox regression analysis, higher BP was associated with a higher risk for CVD (hazard ratio [HR], 1.15 [95% CI, 1.12-1.19]; P for trend <0.001), end-stage renal disease (HR, 1.29 [95% CI, 1.22-1.37]; P for trend <0.001), and all-cause mortality (HR, 1.09 [95% CI, 1.06-1.13]; P for trend <0.001) than BP <120/80 mm Hg. In subgroup analysis, the association between BP and CVD showed a different trend in participants taking antihypertensives compared with those not using antihypertensive drugs. When comparing BP-treated individuals to untreated individuals, a significant interaction in the association between BP categories and end-stage renal disease was observed.

CONCLUSIONS

The new intensive BP target proposed by 2021 Kidney Disease: Improving Global Outcomes should be applied to patients with chronic kidney disease in a personalized and advisory manner.

Impact of smoking reduction on lung cancer risk in patients with COPD who smoked fewer than 30 pack-years: a nationwide population-based cohort study

BACKGROUND

The effects of smoking reduction on the incidence of lung cancer in patients with chronic obstructive pulmonary disease (COPD) are not well known. This study aimed to investigate the effects of changes in smoking habits after COPD diagnosis on lung cancer development in patients who smoked less than 30 pack-years.

METHODS

This nationwide retrospective cohort study included 16,832 patients with COPD who smoked less than 30 pack-years at the time of COPD diagnosis. Based on changes in smoking habits in the health screening examination data, smokers were categorized into three groups: quitters, reducers, and sustainers. The primary outcome was the risk of lung cancer development, which was estimated using the Cox proportional hazards model. We also modelled the amount of smoking reduction as a continuous variable.

RESULTS

During a median follow-up of 4 years, the cumulative incidence of lung cancer was the highest among sustainers, followed by reducers and quitters. Compared with sustainers, reducers (adjusted HR 0.74, 95% CI:0.56-0.98) and quitters (adjusted HR 0.78, 95% CI:0.64-0.96) had a significantly lower risk of lung cancer. Incidence of lung cancer showed a decreasing trend with a decreasing amount of smoking (P for linearity < 0.01).

CONCLUSIONS

In patients with COPD who smoked less than 30 pack-years, smoking reduction and cessation lowered the risk of lung cancer.

Long-Term Autoimmune Inflammatory Rheumatic Outcomes of COVID-19 : A Binational Cohort Study

BACKGROUND

Some data suggest a higher incidence of diagnosis of autoimmune inflammatory rheumatic diseases (AIRDs) among patients with a history of COVID-19 compared with uninfected patients. However, these studies had methodological shortcomings.

OBJECTIVE

To investigate the effect of COVID-19 on long-term risk for incident AIRD over various follow-up periods.

DESIGN

Binational, longitudinal, propensity-matched cohort study.

SETTING

Nationwide claims-based databases in South Korea (K-COV-N cohort) and Japan (JMDC cohort).

PARTICIPANTS

10 027 506 Korean and 12 218 680 Japanese patients aged 20 years or older, including those with COVID-19 between 1 January 2020 and 31 December 2021, matched to patients with influenza infection and to uninfected control patients.

MEASUREMENTS

The primary outcome was onset of AIRD (per appropriate codes from the International Classification of Diseases, 10th Revision) 1, 6, and 12 months after COVID-19 or influenza infection or the respective matched index date of uninfected control patients.

RESULTS

Between 2020 and 2021, among the 10 027 506 Korean participants (mean age, 48.4 years [SD, 13.4]; 50.1% men), 394 274 (3.9%) and 98 596 (0.98%) had a history of COVID-19 or influenza, respectively. After propensity score matching, beyond the first 30 days after infection, patients with COVID-19 were at increased risk for incident AIRD compared with uninfected patients (adjusted hazard ratio, 1.25 [95% CI, 1.18 to 1.31]) and influenza-infected control patients (adjusted hazard ratio, 1.30 [CI, 1.02 to 1.59]). The risk for incident AIRD was higher with more severe acute COVID-19. Similar patterns were observed in the Japanese cohort.

LIMITATIONS

Referral bias due to the pandemic; residual confounding.

CONCLUSION

SARS-CoV-2 infection was associated with increased risk for incident AIRD compared with matched patients without SARS-CoV-2 infection or with influenza infection. The risk for incident AIRD was higher with greater severity of acute COVID-19.

PRIMARY FUNDING SOURCE

National Research Foundation of Korea.

Mid- and long-term risk of atrial fibrillation among breast cancer surgery survivors

BACKGROUND

The risk of incident atrial fibrillation (AF) among breast cancer survivors, especially for younger women, and cancer treatment effects on the association remain unclear. This study aimed to investigate the risk of AF among breast cancer survivors and evaluate the association by age group, length of follow-up, and cancer treatment.

METHODS

Using data from the Korean Health Insurance Service database (2010-2017), 113,232 women newly diagnosed with breast cancer (aged ≥ 18 years) without prior AF history who underwent breast cancer surgery were individually matched 1:5 by birth year to a sample female population without cancer (n = 566,160) (mean[SD] follow-up, 5.1[2.1] years). Sub-distribution hazard ratios (sHRs) and 95% confidence intervals (CIs) considering death as a competing risk were estimated, adjusting for sociodemographic factors and cardiovascular/non-cardiovascular comorbidities.

RESULTS

BCS had a slightly increased AF risk compared to their cancer-free counterparts (sHR 1.06; 95% CI 1.00-1.13), but the association disappeared over time. Younger BCS (age < 40 years) had more than a 2-fold increase in AF risk (sHR 2.79; 95% CI 1.98-3.94), with the association remaining similar over 5 years of follow-up. The increased risk was not observed among older BCS, especially those aged > 65 years. Use of anthracyclines was associated with increased AF risk among BCS (sHR 1.57; 95% CI 1.28-1.92), which was more robust in younger BCS (sHR 1.94; 95% CI 1.40-2.69 in those aged ≤ 50 years).

CONCLUSIONS

Our findings suggest that younger BCS had an elevated risk of incident AF, regardless of the length of follow-up. Use of anthracyclines may be associated with increased mid-to-long-term AF risk among BCS.

Metabolic dysfunction-associated steatotic liver disease and risk of cardiovascular disease

OBJECTIVE

We explored clinical implications of the new definition of metabolic dysfunction-associated steatotic liver disease (MASLD) by assessing its prevalence and associated cardiovascular disease (CVD) risk.

DESIGN

From nationwide health screening data, we identified 9 775 066 adults aged 20-79 who underwent health examination in 2009. Participants were categorised into four mutually exclusive groups: (1) MASLD; (2) MASLD with increased alcohol intake (MetALD); (3) MASLD with other combined aetiology (the three collectively referred to as MASLD/related steatotic liver disease (SLD)); and (4) no MASLD/related SLD. SLD was determined by fatty liver index ≥30. The primary outcome was CVD event, defined as a composite of myocardial infarction, ischaemic stroke, heart failure or cardiovascular death.

RESULTS

The prevalence of MASLD, MetALD and MASLD with other combined aetiology was 27.5%, 4.4% and 1.5%, respectively. A total of 8 808 494 participants without prior CVD were followed up for a median of 12.3 years, during which 272 863 CVD events occurred. The cumulative incidence and multivariable-adjusted risk of CVD were higher in participants with MASLD/related SLD than in those without (HR 1.38 (95% CI 1.37 to 1.39)). Multivariable-adjusted HR (95% CI) of CVD events was 1.39 (1.38 to 1.40) for MASLD, 1.28 (1.26 to 1.30) for MetALD and 1.30 (1.26 to 1.34) for MASLD with other combined aetiology compared to the absence of any of these conditions. CVD risk was also higher in participants with metabolic dysfunction-associated fatty liver disease or non-alcoholic fatty liver disease than in those without the respective condition.

CONCLUSION

Over one-third of Korean adults have MASLD/related SLD and bear a high CVD risk.

Combination of early rhythm control and healthy lifestyle on the risk of stroke in elderly patients with new-onset atrial fibrillation: a nationwide population-based cohort study

Background

The impact of early rhythm control (ERC) combined with healthy lifestyle (HLS) on the risk of ischemic stroke in elderly patients with atrial fibrillation (AF) remains unaddressed.

Objective

To evaluate the impact of combined ERC and HLS on the risk of stroke in elderly patients with new-onset AF.

Methods

Using the Korean National Health Insurance Service database, we included patients aged ≥75 years with new-onset AF from January 2009 to December 2016 (n = 41,315). Patients who received rhythm control therapy within 2 years of AF diagnosis were defined as the ERC group. Non-smoking, non-to-mild alcohol consumption (<105 g/week), and regular exercise were defined as HLS. Subjects were categorized into four groups: group 1 (without ERC and HLS, n = 25,093), 2 (HLS alone, n = 8,351), 3 (ERC alone, n = 5,565), and 4 (both ERC and HLS, n = 2,306). We assessed the incidence of ischemic stroke as the primary outcome, along with admissions for heart failure, all-cause death, and the composite of ischemic stroke, admission for heart failure, and all-cause death.

Results

Median follow-up duration of the study cohort was 3.4 years. After adjusting for multiple variables, groups 2 and 3 were associated with a lower stroke risk (adjusted hazard ratio [aHR]: 95% confidence interval [CI]: 0.867, 0.794-0.948 and 0.713, 0.637-0.798, respectively) than that of group 1. Compared to Group 1, group 4 showed the lowest stroke risk (aHR: 0.694, 95% CI: 0.586-0.822) among all groups, followed by group 3 (0.713, 0.637-0.798) and group 2 (0.857, 0.794-0.948), respectively. Group 4 was associated with the lowest risk of all-cause death (aHR: 0.680, 95% CI: 0.613-0.754) and the composite outcome (aHR: 0.708, 95% CI: 0.649-0.772).

Conclusion

ERC and HLS were associated with a lower risk of ischemic stroke in elderly patients with new-onset AF. Concurrently implementing ERC and maintaining HLS was associated with the lowest risk of death and the composite outcome, with a modest synergistic effect on stroke prevention.

Exposure to earthquakes and development of ischemic heart disease

BACKGROUND

The evidence regarding the effect of earthquake exposure on the development of cardiovascular diseases is limited. This study evaluated the association between the 2016 Gyeongju earthquake, which had a magnitude of 5.8, and over 600 subsequent aftershocks occurring within a year in Korea, with the development of ischemic heart disease (IHD) among residents of Gyeongju.

METHODS

Ten years (2010-2019) of medical records from a randomly selected cohort of residents (n = 540,858) in Gyeongju and 3 control cities were acquired from the national health insurance service. Employing difference-in-difference and meta-analyses, the risks of IHD development of Gyeongju residents before (reference: Sep 2014 to Aug 2015; period 1: Sep 2015 to Aug 2016) and after (period 2: Sep 2016 to Aug 2017; period 3: Sep 2017 to Aug 2018; period 4: Sep 2018 to Aug 2019) the earthquake were estimated.

RESULTS

The monthly average incidence of IHD in Gyeongju was 39.5 persons (per 1,000,000) for reference period and 38.4 persons for period 1. However, the number increased to 58.5 persons in period 2, and 49.8 persons in period 3, following the earthquake. The relative risk (RR) [with a 95% confidence interval] of developing IHD among Gyeongju residents increased by 1.58 times (1.43, 1.73) in period 2, 1.33 times (1.21, 1.46) in period 3, and 1.15 times (1.04, 1.27) in period 4, in comparison to both the control cities and the pre-earthquake reference period. The increase in RR was particularly noticeable among women, adults aged 25-44, and individuals with lower incomes.

CONCLUSIONS

The major earthquake in Korea was associated with an increase in the development of IHD among local residents. Individuals exposed to earthquakes may benefit from cardiovascular health surveillance.

Cancer Risk Following Smoking Cessation in Korea

Importance

Tobacco smoking is associated with increased risk of various cancers, and smoking cessation has been associated with reduced cancer risks, but it is still unclear how many years of smoking cessation are required to significantly reduce the cancer risk. Therefore, investigating the association of smoking cessation with cancer is essential.

Objective

To investigate the time course of cancer risk according to the time elapsed since smoking cessation and the benefits of smoking cessation according to the age at quitting.

Design, Setting, and Participants

This population-based, retrospective cohort study included Korean participants aged 30 years and older who underwent 2 or more consecutive health examinations under the National Health Insurance Service since 2002 and were followed-up until 2019. Data analysis was performed from April to September 2023.

Exposures

Exposures included (1) time-updated smoking status based on biennial changes in smoking status, defined as complete quitters, transient quitters, relapsed quitters, continuous smokers, and never smokers; (2) duration of smoking cessation, defined as years since quitting; and (3) categorical variable for age at quitting.

Main Outcomes and Measures

The primary cancer was ascertained using the cancer registry data: all-site cancer (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes C00-43, C45-96, or D45-D47), lung cancer (ICD-10 code C34), liver cancer (ICD-10 code C22), stomach cancer (ICD-10 code C16), and colorectal cancer (ICD-10 codes C18-20). Hazard ratios (HRs) and 95% CIs were estimated using a Cox proportional hazards regression model with follow-up years as the timescale.

Results

Of the 2 974 820 participants, 1 727 340 (58.1%) were men (mean [SD] age, 43.1 [10.0] years), and 1 247 480 (41.9%) were women (mean [SD] age, 48.5 [9.9] years). Over a mean (SD) follow-up of 13.4 (0.1) years, 196 829 cancer cases were confirmed. Compared with continuous smokers, complete quitters had a lower risk of cancer, with HRs of 0.83 (95% CI, 0.80-0.86) for all cancer sites, 0.58 (95% CI, 0.53-0.62) for lung, 0.73 (95% CI, 0.64-0.82) for liver, 0.86 (95% CI, 0.79-0.93) for stomach, and 0.80 (95% CI, 0.72-0.89) for colorectum. The cancer risk exhibited a slightly higher value for 10 years after quitting compared with continued smoking and then it decreased over time, reaching 50% of the risk associated with continued smoking after 15 or more years. Lung cancer risk decreased 3 years earlier than that of other cancer types, with a larger relative reduction. Regardless of quitting age, a significant reduction in the cancer risk was observed. Quitting before the age of 50 years was associated with a greater reduction in lung cancer risk (HR, 0.43; 95% CI, 0.35-0.53) compared with quitting at age 50 years or later (HR, 0.61; 95% CI, 0.56-0.66).

Conclusions and Relevance

In this population-based retrospective cohort study, sustained smoking cessation was associated with significantly reduced risk of cancer after 10 years since quitting. Quitting at any age helped reduce the cancer risk, and especially for lung cancer, early cessation before middle age exhibited a substantial risk reduction.

The risk of fracture in age-related macular degeneration according to the presence of visual disability: a nationwide cohort study

PURPOSE

To evaluate the association between age-related macular degeneration (AMD) with or without visual disability (VD) and the risk of fracture using the National Health Insurance data in South Korea.

METHODS

In total, 3,894,702 individuals who had taken part in health-screening programs between January 1, 2009, and December 31, 2009, were included in the cohort and followed until December 31, 2019. The participants with VD, which could be related to the severity of AMD, were defined as those with a loss of vision or visual field defect as certified by the Korean government's Ministry of Health and Welfare. The hazard ratio was calculated for groups (control and AMD with/without VD) using the multivariable-adjusted cox regression analysis.

RESULTS

In total, 466,890 participants (11.99%) were diagnosed with fractures during the study period. An increased risk of fracture was observed in individuals with AMD compared with the control (adjusted hazard ratio (aHR), 1.09, 95% confidence interval (CI), 1.06-1.11). Furthermore, among the AMD individuals, an increased risk of fracture was prominent in individuals with VD (aHR 1.17, 95% CI 1.08-1.27) than those without VD (aHR 1.08, 95% CI 1.06-1.11) compared with the reference group (control).

CONCLUSIONS

AMD was associated with an increased risk of fracture even without VD. Prevention for fracture should be considered in AMD patients, especially when accompanied by VD.

Percutaneous coronary intervention versus medical therapy in stable angina: a matched cohort study

OBJECTIVE

It is uncertain whether percutaneous coronary intervention (PCI) in addition to optimal medical therapy (OMT) can reduce adverse clinical events in the long term as compared with OMT alone in patients with pure stable angina.

METHODS

We enrolled patients from 2006 to 2010 using the Korean national insurance data. 58 742 patients with pure stable angina with no history of myocardial infarction (MI) nor PCI were candidate, and finally, 5673 patients in the PCI plus OMT group and 5673 in the OMT alone group were selected with 1:1 propensity matching. They were followed up for 9.3 years.

RESULTS

Primary endpoint, a composite of MI, stroke and cardiac death rate was significantly higher in the PCI group than in the OMT group, 13.5/1000 vs 11.5/1000 person-year with HR of 1.18 (95% CI 1.06 to 1.32, p=0.003). Individual event rate of MI and cardiac death rate was higher in the PCI group than in the OMT group at 9.3 years, 2.9 vs 2.1 (HR 1.38, 95% CI 1.09 to 1.7, p=0.009) and 4.8 vs 3.4/1000 person-year (HR 1.40, 95% CI 1.16 to 1.69, p=0.001), respectively. Revascularisation and total death occurred more in the PCI group as compared with the OMT group, 30.3 vs 8.2 (HR 3.64, 95% CI 3.27 to 4.05, p<0.001) and 13.5 vs 10.6/1000 person-year (HR 1.23, 95% CI 1.12 to 1.40, p<0.001), respectively. In subgroup analysis, the same trend of more event in the PCI group was detected.

CONCLUSIONS

PCI plus OMT was associated with higher rate of primary endpoint of MI, stroke, cardiac death as compared with OMT alone in patients with pure stable angina at 9.3-year follow-up in large population.

Non-indicated initiation of proton pump inhibitor and risk of adverse outcomes in patients with underlying chronic kidney disease: a nationwide, retrospective, cohort study

OBJECTIVE

Evidence related to the risk of kidney damage by proton pump inhibitor (PPI) initiation in patients with 'underlying' chronic kidney disease (CKD) remains scarce, although PPI use is generally associated with acute interstitial nephritis or incident CKD. We aimed to investigate the association between PPI initiation and the risk of adverse outcomes in patients with CKD in the absence of any deterministic indications for PPI usage.

DESIGN

Retrospective observational study.

SETTING

Korea National Health Insurance Service database from 2009 to 2017.

PARTICIPANTS

A retrospective cohort of new PPI and histamine H2-receptor antagonists (H2RA) users among people with CKD. Patients with a history of gastrointestinal bleeding or those who had an endoscopic or image-based upper gastrointestinal tract evaluation were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The study subjects were followed to ascertain clinical outcomes including mortality, end-stage kidney disease (ESKD), myocardial infarction and stroke. The HRs of outcomes were measured using a Cox regression model after adjusting for multiple variables. We applied an inverse probability of treatment weighting (IPTW) model to control for residual confounders.

RESULTS

We included a total of 1038 PPI and 3090 H2RA users without deterministic indications for treatment. IPTW-weighted Cox regression analysis showed that PPI initiation was more significantly associated with a higher ESKD risk compared with that of H2RA initiation (adjusted HR 1.72 (95% CI 1.19 to 2.48)), whereas the risks of mortality or cardiovascular outcomes were similar between the two groups. In the subgroup analysis, multivariable Cox regression analysis showed that the association between PPI use and the progression to ESKD remained significant in non-diabetic and low estimated glomerular filtration rate (<60 mL/min/1.73 m2) groups (adjusted HR 1.72 (95% CI 1.19 to 2.48) and 1.63 (95% CI 1.09 to 2.43), respectively).

CONCLUSIONS

Initiation of PPI administration may not be recommended in patients with CKD without deterministic indication, as their usage was associated with a higher risk of ESKD.

Utilizing temporal pattern of adverse event reports to identify potential late-onset adverse events

OBJECTIVES

Through the use of FDA adverse event reporting system (FAERS) dataset, this study analyzes the pattern of time-to-event (TTE) for drugs and adverse events, and suggest ways to identify candidate late-onset events for monitoring.

METHODS

The duration between administration date of the drug and the onset of adverse events was explored with using FAERS data from 2012-2021. The fold change of proportional reporting ratios or reporting odds ratios were calculated to identify enriched events in the later period and to suggest the late-onset events for further monitoring. To compare the findings, we used the claims database of the Korean National Health Insurance Service (NHIS).

RESULTS

A total of 1,426,781 reports were included. The median TTE was 10 days (interquartile range [IQR]: 0-98 days), with 11.5% (n = 164,093) reporting events that occurred at least one year after administration. TTE and fold change analysis captured historical cases of late-onset events, while generating an additional less-explored list of events. The results for tumor necrosis factor (TNF) inhibitors were compared using the NHIS dataset.

CONCLUSION

Our study provides a comprehensive analysis of the FAERS dataset, focusing on TTE data. Periodic summarization of reports would be helpful in monitoring the late-onset events.

Bipolar disorder and the risk of cardiometabolic diseases, heart failure, and all-cause mortality: a population-based matched cohort study in South Korea

The association of bipolar disorder (BD) with the risk of cardiometabolic diseases and premature death in Asians needs to be further determined. Relatively less attention has been paid to heart failure (HF) among cardiometabolic outcomes. We analyzed the Korean National Health Insurance Service database (2002-2018) for this population-based, matched cohort study. The hazards of ischemic stroke, ischemic heart disease (IHD), hospitalization for HF (hHF), composite cardiometabolic diseases, and all-cause mortality during follow-up were compared between individuals with BD (n = 11,329) and 1:1-matched controls without psychiatric disorders among adults without cardiometabolic disease before or within 3 months of baseline. Hazards of outcomes were higher in individuals with BD than in matched controls (adjusted hazard ratios [95% confidence intervals]: 1.971 [1.414-2.746] for ischemic stroke, 1.553 [1.401-1.721] for IHD, 2.526 [1.788-3.567] for hHF, 1.939 [1.860-2.022] for composite cardiometabolic diseases, and 2.175 [1.875-2.523] for all-cause mortality) during follow-up. Associations between BD and outcome hazards were more prominent in younger individuals (p for interaction < 0.02, except for ischemic stroke) and women (p for interaction < 0.04, except for hHF). Screening and preventive measures for cardiometabolic deterioration and early mortality may need to be intensified in individuals with BD, even in young adults, especially women.

Bone-targeting agents in major solid tumour metastases: a multinational cohort study

OBJECTIVE

To describe the epidemiology, clinical characteristics and utilisation patterns of bone-targeting agents (BTAs) in patients with bone metastases from breast, prostate and lung cancer.

METHODS

This is a multinational retrospective cohort study including patients with three major solid tumours (breast, prostate and lung cancer) and newly initiated on BTAs (ie, denosumab, zoledronic acid and pamidronate). Records were retrieved from nationwide health databases from Hong Kong and Taiwan (HK and TW: 2013-2017) and Korea (KR: 2012-2016). Descriptive analyses included the annual incidence rates of bone metastases and the cumulative incidence curves of BTA initiation. We used Sankey diagrams to visualise the dynamic BTA utilisation patterns.

RESULTS

The annual incidence rate of bone metastases ranged from 3.5% to 4.5% in TW, from 9.6% to 10.3% in HK and from 2.9% to 3.8% in KR. We identified 14.1% (5127), 9.3% (883) and 9.4% (4800) of patients with bone metastases newly initiated on BTAs in TW, HK and KR, respectively. The most frequently used BTA in TW (67.1%) and HK (51.9%) was denosumab, while in KR (84.8%) it was zoledronic acid. Sankey diagrams indicated the proportion of patients remaining on denosumab was highest in TW and HK, while it was zoledronic acid in KR. Specifically, in TW, patients who were on bisphosphonates or had discontinued treatment frequently switched to or reinitiated denosumab.

CONCLUSIONS

We found the rate of BTA utilisation remained low across all sites and tumour types in recent years. The dynamic utilisation patterns of BTAs provide better understanding of the treatment landscape for future evaluation of associated outcomes of patients.

Identification of acute myocardial infarction and stroke events using the National Health Insurance Service database in Korea

OBJECTIVES

The escalating burden of cardiovascular disease (CVD) is a critical public health issue worldwide. CVD, especially acute myocardial infarction (AMI) and stroke, is the leading contributor to morbidity and mortality in Korea. We aimed to develop algorithms for identifying AMI and stroke events from the National Health Insurance Service (NHIS) database and validate these algorithms through medical record review.

METHODS

We first established a concept and definition of "hospitalization episode," taking into account the unique features of health claims-based NHIS database. We then developed first and recurrent event identification algorithms, separately for AMI and stroke, to determine whether each hospitalization episode represents a true incident case of AMI or stroke. Finally, we assessed our algorithms' accuracy by calculating their positive predictive values (PPVs) based on medical records of algorithm- identified events.

RESULTS

We developed identification algorithms for both AMI and stroke. To validate them, we conducted retrospective review of medical records for 3,140 algorithm-identified events (1,399 AMI and 1,741 stroke events) across 24 hospitals throughout Korea. The overall PPVs for the first and recurrent AMI events were around 92% and 78%, respectively, while those for the first and recurrent stroke events were around 88% and 81%, respectively.

CONCLUSIONS

We successfully developed algorithms for identifying AMI and stroke events. The algorithms demonstrated high accuracy, with PPVs of approximately 90% for first events and 80% for recurrent events. These findings indicate that our algorithms hold promise as an instrumental tool for the consistent and reliable production of national CVD statistics in Korea.

Incidence and case fatality of stroke in Korea, 2011-2020

OBJECTIVES

Stroke remains the second leading cause of death in Korea. This study was designed to estimate the crude, age-adjusted and age-specific incidence rates, as well as the case fatality rate of stroke, in Korea from 2011 to 2020.

METHODS

We utilized data from the National Health Insurance Services from January 1, 2002 to December 31, 2020, to calculate incidence rates and 30-day and 1-year case fatality rates of stroke. Additionally, we determined sex and age-specific incidence rates and computed age-standardized incidence rates by direct standardization to the 2005 population.

RESULTS

The crude incidence rate of stroke hovered around 200 (per 100,000 person-years) from 2011 to 2015, then surged to 218.4 in 2019, before marginally declining to 208.0 in 2020. Conversely, the age-standardized incidence rate consistently decreased by 25% between 2011 and 2020. When stratified by sex, the crude incidence rate increased between 2011 and 2019 for both sexes, followed by a decrease in 2020. Age-standardized incidence rates displayed a downward trend throughout the study period for both sexes. Across all age groups, the 30-day and 1-year case fatality rates of stroke consistently decreased from 2011 to 2019, only to increase in 2020.

CONCLUSIONS

Despite a decrease in the age-standardized incidence rate, the total number of stroke events in Korea continues to rise due to the rapidly aging population. Moreover, 2020 witnessed a decrease in incidence but an increase in case fatality rates.

Incidence and case fatality of acute myocardial infarction in Korea, 2011-2020

OBJECTIVES

Cardiovascular diseases are a leading cause of mortality worldwide, and acute myocardial infarction (AMI) is particularly fatal condition. We evaluated the incidence and case fatality rates of AMI in Korea from 2011 to 2020.

METHODS

We utilized data from the National Health Insurance Services to calculate crude, age-standardized, and age-specific incidence rates, along with 30-day and 1-year case fatality rates, of AMI from 2011 to 2020. Age-standardized incidence rates were determined using direct standardization to the 2005 population.

RESULTS

The crude incidence rate of AMI per 100,000 person-years consistently increased from 44.7 in 2011 to 68.3 in 2019, before decreasing slightly to 66.2 in 2020. The age-standardized incidence rate of AMI displayed a 19% rise from 2011 to 2019, followed by a slight decline in 2020. The increasing trend for AMI incidence was more pronounced in males than in females. Both 30-day and 1-year case fatality rates remained stable among younger individuals but showed a decrease among older individuals. There was a minor surge in case fatality in 2020, particularly among recurrent AMI cases.

CONCLUSIONS

Over the past decade, the AMI incidence rate in Korea has consistently increased, with a slight downturn in 2020. The case fatality rate has remained relatively stable except for a minor increase in 2020. This study provides data for continuous surveillance, the implementation of targeted interventions, and the advancement of research aimed at AMI in Korea.

Identifying pregnancy episodes and estimating the last menstrual period using an administrative database in Korea: an application to patients with systemic lupus erythematosus

OBJECTIVES

This study developed an algorithm for identifying pregnancy episodes and estimating the last menstrual period (LMP) in an administrative claims database and applied it to investigate the use of pregnancy-incompatible immunosuppressants among pregnant women with systemic lupus erythematosus (SLE).

METHODS

An algorithm was developed and applied to a nationwide claims database in Korea. Pregnancy episodes were identified using a hierarchy of pregnancy outcomes and clinically plausible periods for subsequent episodes. The LMP was estimated using preterm delivery, sonography, and abortion procedure codes. Otherwise, outcome-specific estimates were applied, assigning a fixed gestational age to the corresponding pregnancy outcome. The algorithm was used to examine the prevalence of pregnancies and utilization of pregnancy-incompatible immunosuppressants (cyclophosphamide [CYC]/mycophenolate mofetil [MMF]/methotrexate [MTX]) and non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy in SLE patients.

RESULTS

The pregnancy outcomes identified in SLE patients included live births (67%), stillbirths (2%), and abortions (31%). The LMP was mostly estimated with outcome-specific estimates for full-term births (92.3%) and using sonography procedure codes (54.7%) and preterm delivery diagnosis codes (37.9%) for preterm births. The use of CYC/MMF/MTX decreased from 7.6% during preconception to 0.2% at the end of pregnancy. CYC/MMF/MTX use was observed in 3.6% of women within 3 months preconception and 2.5% during 0-7 weeks of pregnancy.

CONCLUSIONS

This study presents the first pregnancy algorithm using a Korean administrative claims database. Although further validation is necessary, this study provides a foundation for evaluating the safety of medications during pregnancy using secondary databases in Korea, especially for rare diseases.

Cancer Risk According to Alcohol Consumption Trajectories: A Population-based Cohort Study of 2.8 Million Korean Men

BACKGROUND

Alcohol drinking behaviors change temporally and can lead to changes in related cancer risks; previous studies have been unable to identify the association between the two using a single-measurement approach. Thus, this study aimed to investigate the association of drinking trajectories with the cancer risk in Korean men.

METHODS

A trajectory analysis using group-based trajectory modeling was performed on 2,839,332 men using data on alcohol drinking levels collected thrice during the Korean National Health Insurance Service's general health screening program conducted between 2002 and 2007. Cox proportional hazards regression was performed to evaluate the associations between drinking trajectories and cancer incidence, after adjustments for age, income, body mass index, smoking status, physical activity, family history of cancer, and comorbidities.

RESULTS

During 10.5 years of follow-up, 189,617 cancer cases were recorded. Six trajectories were determined: non-drinking, light, moderate, decreasing-heavy, increasing-heavy, and steady-heavy. Light-to-heavy alcohol consumption increased the risk for all cancers combined in a dose-dependent manner (adjusted hazard ratio [aHR] 1.03; 95% confidence interval [CI], 1.02-1.05 for light drinking, aHR 1.06; 95% CI 1.05-1.08 for moderate drinking, aHR 1.19; 95% CI, 1.16-1.22 for decreasing-heavy drinking, aHR 1.23; 95% CI, 1.20-1.26 for increasing-heavy drinking, and aHR 1.33; 95% CI, 1.29-1.38 for steady-heavy drinking [P-trend <0.001]). Light-to-heavy alcohol consumption was linked to lip, oral cavity, pharyngeal, esophageal, colorectal, laryngeal, stomach, and gallbladder and biliary tract cancer risks, while heavy alcohol consumption was associated with hepatic, pancreatic, and lung cancer risks. An inverse association was observed for thyroid cancer. The cancer risks were lower for decreasing-heavy drinkers, compared to steady-heavy drinkers.

CONCLUSION

No safe drinking limits were identified for cancer risks; reduction in heavy intake had protective effects.

Is Thyroid Dysfunction Associated with Unruptured Intracranial Aneurysms? A Population-Based, Nested Case-Control Study from Korea

Background: Few risk factors for the development of intracranial aneurysms (IAs) are known. We investigated the potential role of thyroid diseases in IA development using nationwide real-world data. Methods: A nested case-control study within the National Health Insurance Service-National Sample Cohort data from 2002 to 2019 was performed. A total of 5335 patients with unruptured IA were matched by age and sex with 80,025 controls at a ratio of 1:15. We estimated the odds ratios (ORs) and corresponding confidence intervals [CIs] between thyroid diseases and unruptured IA using a multivariable conditional logistic regression model. Results: Tobacco smoking, use of antihypertensive medication, and hypothyroidism were significantly associated with an elevated risk for unruptured IA in univariate analysis. In multivariable analysis, a history of hypothyroidism was associated with unruptured IA (adjusted OR: 1.46 [CI: 1.26-1.69]). Among patients with hypothyroidism, long-term use of thyroid hormone for >5 years was associated with a reduced risk for unruptured IA (adjusted OR: 0.69 [CI: 0.48-0.99]). A history of hyperthyroidism was associated with a reduced risk for unruptured IAs (adjusted OR: 0.71 [CI: 0.54-0.93]). In secondary analyses of the data according to sex, the respective observed associations between hypothyroidism and hyperthyroidism and the risk of IAs were found to be statistically significant in females but not in males. Conclusions: Hypothyroidism is associated with an increased risk of unruptured IAs, whereas hyperthyroidism is associated with a reduced risk. Overall, the findings suggest that thyroid hormones may play a protective role in the development of unruptured IAs. Further studies are needed to clarify potential direct causality and the biologic mechanisms relating thyroid dysfunction and unruptured IA.

Cardiovascular and Mortality Risks in Young Health Screening Examinees With Marginal Estimated GFR

Introduction

Additional evidence is necessary to interpret kidney function parameters in young adults, particularly in those with marginal estimated glomerular filtration rate (eGFR) values. Therefore, we aimed to investigate the association between eGFR and adverse outcomes in general young adults.

Methods

We performed a nationwide retrospective cohort study using the health-screening database of South Korea. We included young adults aged 20-39 years without a history of major adverse cardiovascular events (MACE) or kidney failure, who underwent nationwide health screening in 2012. The study exposure was eGFR categorized into 15 ml/min per 1.73 m2 intervals. The risks of all-cause mortality and MACE were calculated using Cox regression analysis, adjusted for various clinicodemographic characteristics.

Results

In total, 3,132,409 young adults were included in this study. During a median follow-up of 7.3 years, marginal eGFR (60-75 ml/min per 1.73 m2) was not significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio [aHR], 0.80 [0.74-0.87]). The results were similar for MACE outcomes (aHR, 0.94 [0.87-1.01]). Although the presence of dipstick albuminuria had a significant interaction with the association between eGFR categories and all-cause mortality (interaction term P = 0.028), the risks of all-cause mortality were not significantly higher (aHR, 0.98 [0.62, 1.55]) in those with albuminuria and eGFR 60-75 ml/min per 1.73 m2.

Conclusion

Marginal eGFR was not associated with higher risks of all-cause mortality and MACE in general young adults. Additional clinical investigations for incidentally found marginal eGFR values may be discouraged in general young adults.

Real-world data analysis on effectiveness of integrative therapies: A practical guide to study design and data analysis using healthcare databases

Real world data (RWD) is increasingly used to investigate health outcomes and treatment efficacy in the field of integrative medicine. Due to the fact that the majority of RWDs are not intended for research, their secondary use in research necessitates complex study designs to account for bias and confounding. To conduct a robust analysis of RWD in integrative medicine, a comprehensive study design process that reflects the characteristics of integrative therapies is necessary. In this paper, we present a guide for designing comparative effectiveness RWE research in integrative medicine. We discuss key factors to consider when selecting RWDs for research on integrative medicine. We provide practical steps for developing a research question, formulating the PICOT objectives (population, intervention, comparator, outcome, and time horizon), and selecting and defining covariates with a summary table. Specific study designs are depicted with corresponding diagrams. Finally, data analysis procedures are introduced. We hope this article clarifies the importance of RWE research design and related processes in order to improve the rigor of RWD studies in the field of integrative medicine research.

Burden of Herpes Zoster in Individuals with Immunocompromised Conditions and Autoimmune Diseases in the Republic of Korea: A Nationwide Population-Based Database Study

INTRODUCTION

To estimate herpes zoster (HZ) incidence rate (IR) and economic burden in individuals with immunocompromised conditions and autoimmune diseases (IC/AID) in the Republic of Korea (ROK).

METHODS

The nationwide Health Insurance Review and Assessment Service database was used to identify HZ cases from 2016 to 2020 in ROK. HZ and non-HZ IC/AID cases were matched 1:3 using age, sex, institution, Charlson comorbidity index, IC/AID, and index date. Annual HZ IRs/1000 persons and 1-year HZ-associated all-cause direct medical costs for IC/AID cases were calculated.

RESULTS

Among 65,976 individuals with IC/AID (mean age 57.14 years [standard deviation 14.1]; 64.94% female), annual HZ IR (95% confidence interval) fluctuated from 2016 to 2020, averaging 23.41/1000 persons (22.21-24.62) and was higher in women (26.85 [25.40-28.31]) than men (18.96 [18.03-19.89]). IRs were highest in individuals aged ≥ 50 years, and in those with transplants (including solid organ and hematopoietic stem cell transplants; 37.12 [35.45-38.79]) and hemato-oncology conditions (35.5 [31.6-39.3]). Mean 12-month all-cause direct medical costs were higher in individuals with IC/AID and HZ (4,759,671 Korean Republic won [KRW]; approximately 4046 United States dollar [USD; according to the 2020 conversion rate from UNCTAD; 1 KRW = 0.00085 USD]) than those without HZ (3,786,658 KRW; 3219 USD).

CONCLUSION

Individuals with IC/AID have a substantial disease and economic burden from HZ in ROK, highlighting the need for appropriate HZ prevention measures in the IC/AID population.

Analysis of Long-Term Medical Expenses in Vertebral Fracture Patients

Background

The objective of this study was to analyze the direct medical expenses of a vertebral fracture cohort (VC) and a matched cohort (MC) over 5 years preceding and following the fracture, analyze the duration of the rise in medical expenses due to the fracture, and examine whether the expenses vary with age group, utilizing a national claims database.

Methods

Subjects with vertebral fractures and matched subjects were chosen from the National Health Insurance Service Sample cohort (NHIS-Sample) of South Korea. Patients with vertebral fractures were either primarily admitted to acute care hospitals (index admissions) or those who received kyphoplasty or vertebroplasty during the follow-up period (2002-2015). A risk-set matching was performed using 1 : 5 random sampling to simulate a real-world situation. Individual-level direct medical expenses per quarter were calculated for 5 years prior and subsequent to the vertebral fracture. In this analysis using a comparative interrupted time series design, we examined the direct medical expenses of a VC and an MC.

Results

A total of 3,923 incident vertebral fracture patients and 19,615 matched subjects were included in this study. The mean age was 75.5 ± 7.4 years, and 69.5% were women. The mean difference in medical expenses between the two groups increased steadily before the fracture. The medical expenses of the VC peaked in the first quarter following the fracture. The cost changes were 1.82 times higher for the VC than for the MC (95% confidence interval, 1.62-2.04; p < 0.001) in the first year. Subsequently, there were no differential changes in medical expenses between the two groups (p > 0.05). In the < 70-year subgroup, there were no differential changes in medical expenses between the two groups (p > 0.05). However, in the ≥ 80-year subgroup, the cost changes for the VC were higher than those for the MC up to 5 years after time zero.

Conclusions

Based on our study results, we suggest that health and medical policies for vertebral fractures should be designed to last up to approximately 1 year after the fracture. Health policies should be differentiated according to age group.

Outcomes of SGLT-2i and GLP-1RA Therapy Among Patients With Type 2 Diabetes and Varying NAFLD Status

Importance

Nonalcoholic fatty liver disease (NAFLD) is a cardiovascular risk factor, but whether sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) are associated with reduced cardiovascular risk in patients with type 2 diabetes (T2D) and concomitant NAFLD remains uncertain.

Objective

To investigate the outcomes of SGLT-2i and GLP-1RA therapy among patients with T2D varied by the presence or absence of NAFLD.

Design, Setting, and Participants

This retrospective, population-based, nationwide cohort study used an active-comparator new-user design. Two distinct new-user active-comparator cohorts of patients aged 40 years and older who initiated SGLT-2i or GLP-1RA were propensity score matched to patients who initiated dipeptidyl peptidase-4 inhibitors (DPP-4i). The study was conducted in South Korea from January 2013 to December 2020, and data analysis was conducted from October 2022 to March 2023.

Main Outcomes and Measures

The main outcomes were (1) major adverse cardiovascular events (MACE), a composite end point of hospitalization for myocardial infarction, hospitalization for stroke, and cardiovascular death, and (2) hospitalization for heart failure (HHF). Cox proportional hazards models were used to estimate hazard ratios (HRs). The Wald test was applied to assess heterogeneity by NAFLD.

Results

After 1:1 propensity score matching, 140 438 patients were retrieved in the first cohort (SGLT-2i vs DPP-4i; mean [SD] age, 57.5 [10.3] years; 79 633 [56.7%] male) and 34 886 patients were identified in the second cohort (GLP-1RA vs DPP-4i; mean [SD] age, 59.5 [10.5] years; 17 894 [51.3%] male). Compared with DPP-4i, SGLT-2i therapy was associated with a lower risk of MACE (HR, 0.78 [95% CI, 0.71-0.85]) and HHF (HR, 0.62 [95% CI, 0.48-0.81]). GLP-1RA therapy was associated with a decreased risk of MACE (HR, 0.49 [95% CI, 0.39-0.62]) but had statistically nonsignificant findings regarding HHF (HR, 0.64 [95% CI, 0.39-1.07]). Stratified analysis by NAFLD status yielded consistent results for SGLT-2i (MACE with NAFLD: HR, 0.73 [95% CI, 0.62-0.86]; without NAFLD: HR, 0.81 [95% CI, 0.72-0.91]; HHF with NAFLD: HR, 0.76 [95% CI, 0.49-1.17]; without NAFLD: HR, 0.56 [95% CI, 0.40-0.78]) and for GLP-1RA (MACE with NAFLD: HR, 0.49 [95% CI, 0.32-0.77]; without NAFLD: HR, 0.49 [95% CI, 0.37-0.65]; HHF with NAFLD: HR, 0.82 [95% CI, 0.38-1.76]; without NAFLD: HR, 0.54 [95% CI, 0.27-1.06]).

Conclusions and Relevance

In this population-based cohort study, SGLT-2i therapy was associated with a decreased risk of MACE and HHF, while GLP-1RA therapy was associated with a decreased risk of MACE among patients with T2D, irrespective of baseline NAFLD status.

Risk of gastric cancer among long-term proton pump inhibitor users: a population-based cohort study

PURPOSE

To elucidate whether long-term proton pump inhibitor (PPI) users have an increased gastric cancer (GC) risk.

METHODS

We searched the 2009-2019 Korean National Health Insurance Services Database for patients aged > 40 years who claimed for Helicobacter pylori eradication (HPE) during 2009-2014. The GC incidence following a PPI exposure of > 180 cumulative defined daily dose (cDDD) and that following an exposure of < 180 cDDD were compared. The outcome was GC development at least 1 year following HPE. A propensity score (PS)-matched dataset was used for analysis within the same quartiles of the follow-up duration. Additionally, dose-response associations were assessed, and the mortality rates were compared between long-term PPI users and non-users.

RESULTS

After PS matching, 144,091 pairs of PPI users and non-users were analyzed. During a median follow-up of 8.3 (interquartile range, 6.8-9.6) years, 1053 and 948 GC cases in PPI users and non-users, respectively, were identified, with the GC incidence (95% confidence interval (CI)) being 0.90 (0.85-0.96) and 0.81 (0.76-0.86) per 1000 person-years, respectively. The adjusted hazard ratio (aHR) for GC with PPI use was 1.15 (95% CI, 1.06-1.25). Among PPI users, patients in the highest tertile for annual PPI dose showed higher GC development than those in the lowest tertile (aHR (95% CI): 3.87 (3.25-4.60)). GC-related mortality did not differ significantly between PPI users and non-users.

CONCLUSION

In this nationwide analysis in Korea, where the GC prevalence is high, long-term PPI use after HPE showed a significant increase in GC, with a positive dose-response relationship.