Korea National Health Insurance Service Research Articles

COVID-19 vaccination and ocular adverse events: a self-controlled case series study from the entire South Korean population

This study aimed to assess the risk of ocular adverse events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), non-infectious uveitis (NIU), non-infectious scleritis (NIS), optic neuritis (ON), ischemic optic neuropathy (ION), and ocular motor cranial nerve palsy (OMCNP), following coronavirus disease 2019 (COVID-19) vaccination. Population-based self-controlled case series METHODS: This study utilized nationwide claims and vaccination data provided by the Korea National Health Insurance Service and Korea Disease Control and Prevention Agency. From the entire South Korean population of 52 million individuals, patients with incident RAO, RVO, anterior NIU, non-anterior NIU, NIS, ON, ION, or OMCNP between January 2021 and March 2022 were included. The post-vaccination risk period was defined as up to 56 days after COVID-19 vaccination. The relative incidence rate ratios (IRRs) for RAO, RVO, anterior NIU, non-anterior NIU, NIS, ON, ION, and OMCNP during the risk periods were measured using conditional Poisson regression. The study included 6,590, 70,120, 137,958, 17,921, 15,492, 2,039, 49,089, and 11,312 cases of incident RAO, RVO, anterior NIU, non-anterior NIU, NIS, ON, ION, and OMCNP, respectively. The IRRs (95% confidence interval) during the early risk period (0-28 days) were 0.95 (0.88-1.01), 0.96 (0.94-0.98), 0.93 (0.91-0.94), 0.93 (0.89-0.96), 0.96 (0.92-1.01), 1.04 (0.92-1.18), 0.98 (0.95-1.00), and 0.91 (0.86-0.96), respectively. In the late risk period (29-56 days), the IRRs were 0.96 (0.89-1.03), 0.93 (0.91-0.96), 0.96 (0.95-0.98), 1.00 (0.95-1.04), 0.96 (0.91-1.01), 1.00 (0.87-1.15), 1.01 (0.98-1.04), and 0.95 (0.90-1.01), respectively. COVID-19 vaccination did not increase the risk of incident RAO, RVO, anterior NIU, non-anterior NIU, NIS, ON, ION, or OMCNP during the post-vaccination period.

Dementia Incidence in Survivors of Multiple Myeloma: A National Case-Control Study Conducted in Korea (The CAREMM-2106 Study)

BackgroundDementia, a growing global health issue, affects older adults and specific groups like long-term cancer survivors. The link between cancer survival and dementia is debated. Multiple myeloma (MM), a common blood cancer in older adults, is often linked with cognitive issues. This study investigated dementia incidence in long-term MM survivors using Korean national data. MethodsA retrospective case-control study used data from the Korea National Health Insurance Service (KNHIS), covering about 50 million Koreans. Patients diagnosed with MM between 2009 and 2020 formed the case cohort, while the control cohort included matched individuals without MM using propensity-score matching. Analyzing baseline characteristics, comorbidities, and socioeconomic status, the primary outcome was dementia incidence identified via ICD-10 codes. Statistical methods included Kaplan-Meier plots, cause-specific and Fine–Gray subdistribution hazard models, and a 3-year landmark analysis for immortal time bias. ResultsThe study included 33,864 patients, with 16,932 in each cohort. The overall cumulative dementia incidence was lower in the MM cohort compared to controls. However, in the first 3 years, MM patients had a higher dementia risk (HR: 1.711, 95% CI, 1.562-1.874) than controls. After 3 years, the risk significantly decreased (HR: 0.625, 95% CI, 0.560-0.696). Age-specific analysis showed a consistent pattern, particularly among MM patients aged 70-79, where dementia risk increased post-3 years. ConclusionThis study reveals a lower long-term dementia risk in MM survivors compared to non-MM individuals. Further prospective studies are needed to confirm these findings and explore the underlying mechanisms.

Dementia incidence varied by anticancer drugs and molecular targeted therapy in a population-based cohort study

Anticancer drugs may affect the incidence of dementia by modulating the common pathophysiology between cancer and dementia. However, there is a paucity of research that focused on anticancer drugs with different mechanisms of action and their associations with subtypes of dementia. Therefore, we aimed to investigate the incidence of dementia according to various groups of anticancer drugs. From the Korea National Health Insurance Service database, our retrospective population-based cohort study enrolled 116,506 cancer patients aged 65 years and older who received anticancer drugs between January 1, 2008 and December 31, 2018. The hazard ratio was determined using Cox proportional hazards regression models, comparing each group of anticancer drugs to all other anticancer drugs, after adjusting for covariates. Antimetabolites (HR = 0.91; 95% CI 0.84–0.97) and molecular targeted therapies (HR = 0.60; 95% CI 0.49–0.74) were associated with a decreased incidence of dementia of the Alzheimer type (DAT), but not with vascular dementia. Among molecular targeted therapies, epidermal growth factor receptor inhibitors (HR = 0.60; 95% CI 0.46–0.79) and multikinase inhibitors (HR = 0.49; 95% CI 0.27–0.89) were associated with a low incidence of DAT only. Our findings highlight the potential for targeted repurposing of anticancer drugs to prevent dementia.

Machine learning analysis with population data for prepregnancy and perinatal risk factors for the neurodevelopmental delay of offspring

Neurodevelopmental disorders (NDD) in offspring are associated with a complex combination of pre-and postnatal factors. This study uses machine learning and population data to evaluate the association between prepregnancy or perinatal risk factors and the NDD of offspring. Population-based retrospective cohort data were obtained from Korea National Health Insurance Service claims data for 209,424 singleton offspring and their mothers who gave birth for the first time in 2007. The dependent variables were motor development disorder (MDD), cognitive development disorder (CDD) and combined overall neurodevelopmental disorder (NDD) from offspring. Seventeen independent variables from 2002 to 2007 were included. Random forest variable importance and Shapley Additive Explanation (SHAP) values were calculated to analyze the directions of its associations with the predictors. The random forest with oversampling registered much higher areas under the receiver-operating-characteristic curves than the logistic regression of interaction and non-linearity terms, 79% versus 50% (MDD), 82% versus 52% (CDD) and 74% versus 50% (NDD). Based on random forest variable importance, low socioeconomic status and age at birth were highly ranked. In SHAP values, there was a positive association between NDD and pre- or perinatal outcomes, especially, fetal male sex with growth restriction associated the development of NDD in offspring.

Aspirin versus clopidogrel as a combination therapy with direct oral anticoagulant after coronary stent implantation in patients with atrial fibrillation

Abstract Background Patients with atrial fibrillation (AF) who undergo percutaneous coronary intervention (PCI) are recommended to receive dual antithrombotic therapy including an antiplatelet agent and direct anticoagulants (DOAC). We compared the effectiveness between aspirin and clopidodgrel for a combination therapy with DOAC in this population. Methods We analyzed patient data from the Korea National Health Insurance Service. A total of 9,157 patients with AF who received dual antithrombotic therapy after PCI were included. Patients were classified into the aspirin group and clopidogrel group, and 1:1 propensity score matching (PSM) was performed. The primary ischemic endpoint was a composite of cardiovascular death, myocardial infarction, stroke, or systemic thromboembolism. A major bleeding event was defined as a bleeding event requiring hospitalization. Results After PSM, there were each 2,882 patients each in the aspirin and clopidogrel group. The incidence of the primary ischemic endpoint was similar in the two groups (22.8% vs. 21.8%, in the aspirin and clopidogrel group, hazard ratio [HR] for clopidogrel group: 0.909, 95% confidence interval [CI] 0.815 – 1.014). The incidence of each component of ischemic endpoint did not differ significantly between the two groups. All-cause mortality was increased in the clopidogrel group (HR 1.301, 95% CI 1.000 – 1.692). There was no significant difference in major bleeding events (HR 0.942, 95% CI 0.789 – 1.126). Conclusions For a dual antithrombotic therapy in patients with AF who had undergone PCI, aspirin and clopidogrel did not differ in terms of ischemic outcomes, but the use of aspirin was associated with slightly lower all-cause mortality.

Clinical Implications of Polypharmacy for Patients with New-Onset Atrial Fibrillation Based on Real-World Data: Observations from the Korea National Health Insurance Service Data.

Polypharmacy is commonly observed in atrial fibrillation (AF) and is associated with poorer clinical outcomes. Our study aimed to elucidate the polypharmacy prevalence, its associated risk factors, and its relationship with adverse clinical outcomes using a 'real-world' database. This study included 451,368 subjects without prior history of AF (median age, 54 [interquartile range, 48.0-63.0] years; 207,748 [46.0%] female) from the Korea National Health Insurance Service-Health Screening (NHIS-HealS) database between 2002 and 2013. All concomitant medications prescribed were collected, and the intake of five or more concomitant drugs was defined as polypharmacy. During the follow-up, all-cause death, major bleeding events, transient ischemic attack (TIA) or ischemic stroke, and admission due to worsened heart failure were recorded. Based on up to 7.7 (6.8-8.3) years of follow-up and 768,306 person-years, there were 12,241 cases of new-onset AF identified. Among patients with new-onset AF (40.0% females, median age 63.0 [54.0-70.0] years), the polypharmacy prevalence was 30.9% (3784). For newly diagnosed AF, factors, such as advanced age (with each increase of 10 years, odds ratios (OR) 1.32, 95% confidence interval (CI) 1.26-1.40), hypertension (OR 4.00, 95% CI 3.62-4.43), diabetes mellitus (OR 3.25, 95% CI 2.86-3.70), chronic obstructive pulmonary disease (COPD) (OR 3.00, 95% CI 2.51-3.57), TIA/ischemic stroke (OR 2.36, 95% CI 2.03-2.73), dementia history (OR 2.30, 95% CI 1.06-4.98), end-stage renal disease (ESRD) or chronic kidney disease (CKD) (OR 1.97, 95% CI 1.38-2.82), and heart failure (OR 1.95, 95% CI 1.69-2.26), were found to be independently correlated with the incidence of polypharmacy. Polypharmacy significantly increased the incidence and risk of major bleeding (adjusted hazard ratio (aHR) 1.26, 95% CI 1.12-1.41). The study observed a statistically significant increase in the incidence of all-cause mortality, however, the risk for all-cause mortality elevated but did not show significance (aHR 1.11, 95% CI 0.99-1.24). The risk of stroke and admission for heart failure did not change with polypharmacy. In our investigation using data from a nationwide database, polypharmacy was widespread in new-onset AF population and was related to major bleeding events. However, polypharmacy does not serve as an independent risk factor for adverse outcomes, with exception of major bleeding event. For AF patients, ensuring tailored medication for comorbidities as well as reducing polypharmacy are essential considerations.

Risk of urolithiasis associated with allopurinol versus benzbromarone among patients with gout: a population-based cohort study.

To compare the risk of urolithiasis in gout patients initiating allopurinol, a xanthine oxidase inhibitor, vs benzbromarone, a uricosuric. Using the 2011-2020 Korea National Health Insurance Service database, we conducted a cohort study on gout patients initiating allopurinol vs benzbromarone as the 1st-line urate-lowering treatment (ULT). The primary outcome was a new onset urinary stone. The secondary outcome was a stone requiring intervention. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazard models with a 5:1 ratio propensity-score matching on > 80 variables. Subgroup analyses were done by age, sex, thiazide use, and cardiovascular (CV) risk. 61 300 allopurinol initiators PS-matched on 12 260 benzbromarone initiators were included (mean age 59 years, 79% male). During a mean follow-up of 322 days, 619 urolithiasis cases occurred with an incidence rate of 0.87 per 100 person-years in allopurinol and 1.39 in benzbromarone initiators, showing a HR of 0.64 (95% CI, 0.51-0.80). ∼44% of urinary stones required intervention with a HR of 0.61 (95% CI 0.43-0.88). The lower risk associated with allopurinol compared with benzbromarone persisted across subgroups but was greater in the high than non-high CV risk subgroup (p for interaction = 0.02). This population-based cohort study found that allopurinol compared with benzbromarone was associated with a substantially lower risk of urolithiasis particularly in the presence of the high CV risk. This finding provides important safety information for clinicians' decision-making on ULTs of different mechanisms of action.

Evolutionary changes in metabolic dysfunction-associated steatotic liver disease and risk of hepatocellular carcinoma: A nationwide cohort study.

To determine the association between evolutionary changes in metabolic dysfunction-associated steatotic liver disease (MASLD) status and the risk of hepatocellular carcinoma (HCC) in a nationwide population-based cohort. Information on study participants was derived from the Korea National Health Insurance Service database. The study population consisted of 5,080,410 participants who underwent two consecutive biennial health screenings between 2009 and 2012. All participants were followed up until HCC, death, or 31 December 2020. The association of evolutionary changes in MASLD status, as assessed by the fatty liver index and cardiometabolic risk factors, including persistent non-MASLD, resolved MASLD, incident MASLD, and persistent MASLD, with HCC risk was evaluated using multivariable-adjusted Cox proportional hazards regression. Among the 5,080,410 participants with 39,910,331 person-years of follow-up, 4,801 participants developed HCC. The incidence of HCC in participants with resolved, incident, and persistent MASLD was approximately 2.2-, 2.3-, and 4.7-fold higher, respectively, than that in those with persistent non-MASLD among the Korean adult population. When stratifying the participants according to the evolutionary change in MASLD status, persistent (adjusted hazard ratio [aHR], 2.94; 95% confidence interval [CI], 2.68-3.21; P<0.001), incident (aHR, 1.85; 95% CI, 1.63-2.10; P<0.001), and resolved MASLD (aHR, 1.33; 95% CI, 1.18-1.50; P<0.001) had an increased risk of HCC compared to persistent non-MASLD. The evolutionary changes in MASLD were associated with the differential risk of HCC independent of metabolic risk factors and concomitant medications, providing additional information on the risk of HCC stratification in patients with MASLD.

Risk of Secondary Malignancies After Multiple Myeloma: A Nationwide Case-Control Cohort Study

IntroductionIn light of improved survival rates among multiple myeloma (MM) survivors, we sought to assess their risk of secondary malignancies compared to the general population. Materials and MethodsThis nationwide population-based case-control cohort study utilized the Korea National Health Insurance Service (KNHIS) database incorporating data from 2009 to 2020. We analyzed a total of 7348 patients diagnosed with MM in the case cohort. We selected a control group of 29,351 individuals from the general population without MM, employing a 1:4 propensity score matching approach. Matching criteria included age, sex, and comorbidities to ensure a balanced and reliable comparison. ResultsThe cumulative incidence of any secondary malignancy was significantly higher in the case cohort than the control cohort (Hazard ratio [HR] 1.576, 95% confidence interval [CI], [1.381-1.798]). Hematologic malignancy risk was notably higher in the case cohort (HR 8.026, 95% CI, [5.402-11.924]), especially therapy-related myeloid neoplasms (t-MN) (HR 12.063, 95% CI, [6.839-21.278]). No significant difference was shown in nonhematologic malignancy incidence. In subgroup analysis, transplant-eligible MM patients had a significantly higher incidence of any secondary malignancy (HR 1.104, 95% CI, [1.003-1.214]) than transplant-ineligible patients. The incidence of secondary malignancy in MM patients in the lenalidomide-available era was not significantly increased compared to the prelenalidomide era. ConclusionWhile hematologic malignancies, particularly t-MN, are significantly elevated in MM patients compared to general population, nonhematologic malignancies do not appear to be significantly elevated.

Comparison of current relative value unit-based prices and utility between common surgical procedures, including orthopedic surgeries, in South Korea

BackgroundThe medical pricing system strongly influences physicians’ job satisfaction and patient health outcomes. This study aimed to investigate the current relative value unit (RVU)-based pricing and utility of patients in commonly performed surgical procedures in South Korea.MethodsFifteen common surgical procedures were selected from OECD statistics, and three additional orthopedic procedures were examined. The current pricing of each surgical procedure was retrieved from the Korea National Health Insurance Service, and the corresponding utilities were obtained as quality-adjusted life year (QALY) gains from previous studies. The relationship between the current prices (RVUs) and the patients’ utility (incremental QALY gains/year) was analyzed. Subgroup analysis was performed between fatal and non-fatal procedures and between orthopedic and non-orthopedic procedures.ResultsA significant negative correlation (r = − 0.558, p < 0.001) was observed between RVU and incremental QALY among all 18 procedures. The fatal subgroup had a significantly higher RVU than the non-fatal subgroup (p < 0.05), while the former had a significantly lower incremental QALY than the latter (p < 0.001). Orthopedic procedures showed higher incremental QALY values than non-orthopedic procedures, but they did not show higher prices (RVU).ConclusionsThis paradoxical relationship between current prices and patient utility is attributed to the higher pricing of surgical procedures for fatal and urgent conditions. Orthopedic surgery has been found to be a cost-effective treatment strategy. These findings could contribute to a better understanding of the potential role of incremental QALY in pursuing value-based purchasing or reasonable modification of the current medical fee schedule.

Explainable artificial intelligence for predicting red blood cell transfusion in geriatric patients undergoing hip arthroplasty: Machine learning analysis using national health insurance data.

This study uses machine learning and population data to analyze major determinants of blood transfusion among patients with hip arthroplasty. Retrospective cohort data came from Korea National Health Insurance Service claims data for 19,110 patients aged 65 years or more with hip arthroplasty in 2019. The dependent variable was blood transfusion (yes vs no) in 2019 and its 31 predictors were included. Random forest variable importance and Shapley Additive Explanations were used for identifying major predictors and the directions of their associations with blood transfusion. The random forest registered the area under the curve of 73.6%. Based on random forest variable importance, the top-10 predictors were anemia (0.25), tranexamic acid (0.17), age (0.16), socioeconomic status (0.05), spinal anesthesia (0.05), general anesthesia (0.04), sex (female) (0.04), dementia (0.03), iron (0.02), and congestive heart failure (0.02). These predictors were followed by their top-20 counterparts including cardiovascular disease, statin, chronic obstructive pulmonary disease, diabetes mellitus, chronic kidney disease, peripheral vascular disease, liver disease, solid tumor, myocardial infarction and hypertension. In terms of max Shapley Additive Explanations values, these associations were positive, e.g., anemia (0.09), tranexamic acid (0.07), age (0.09), socioeconomic status (0.05), spinal anesthesia (0.05), general anesthesia (0.04), sex (female) (0.02), dementia (0.03), iron (0.04), and congestive heart failure (0.03). For example, the inclusion of anemia, age, tranexamic acid or spinal anesthesia into the random forest will increase the probability of blood transfusion among patients with hip arthroplasty by 9%, 7%, 9% or 5%. Machine learning is an effective prediction model for blood transfusion among patients with hip arthroplasty. The high-risk group with anemia, age and comorbid conditions need to be treated with tranexamic acid, iron and/or other appropriate interventions.

All-cause and cause-specific mortality in patients with Behçet disease versus the general population.

The comparative risk of cause-specific mortality in patients with Behçet disease (BD) vs. the general population is not known. To compare the risk of all-cause and cause-specific mortality in patients with BD vs. the general population. Using data from the Korea National Health Insurance Service database for the period 2002-20, we conducted a cohort study comparing patients with BD with the general population, matched according to age and sex (1 : 4 ratio). We used Cox proportional hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality. Subgroup analyses by age and sex were done. We included 24 669 patients with BD and 98 676 age- and sex-matched controls [mean (SD) age 40.5 (12.9) years; 34% male]. During a mean follow-up of 11.9 years, the incidence rate (IR) of death per 100 person-years was 0.36 in patients with BD and 0.29 in controls [hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.20-1.38]. The risk of mortality was highest in the first year after BD diagnosis (HR 2.66, 95% CI 2.09-3.40). Patients with BD died more often in this period as a result of malignancy (HR 1.96, 95% CI 1.30-2.98); cardiovascular (HR 2.68, 95% CI 1.45-4.97), gastrointestinal (HR 3.50, 95% CI 1.35-9.07) and respiratory disease (HR 5.00, 95% CI 1.34-18.62); and infection (HR 3.33, 95% CI 1.02-10.92). Mortality as a result of neurological (HR 1.58, 95% CI 1.06-2.35) or genitourinary disease (HR 2.20, 95% CI 1.43-3.37) was also more common in patients with BD during the overall follow-up. Subgroup analyses showed consistent results. The risk of cardiovascular mortality vs. the general population was higher in younger patients (P = 0.006) and the risk of gastrointestinal mortality was increased in women vs. men (P = 0.04). This population-based cohort study revealed that the first year after diagnosis is the highest risk period for excess mortality in people with BD. The mortality burden in BD derives from a wide spectrum of organ involvement and should serve as a warning to clinicians about the systemic nature of the disease.

All-Cause Death and Major Adverse Events in Atrial Fibrillation with Frailty: Observations from the Korea National Health Insurance Service Data.

Atrial fibrillation (AF) is an indicator of frailty in old patients. This study aimed to investigate the effect of frailty on the use of oral anticoagulants (OAC) and clinical outcomes in a nationwide cohort of patients with new-onset AF. This study included 451,368 participants without AF from the Korea National Health Insurance Service-Health Screening cohort between 2002 and 2009. The Hospital Frailty Risk Score was retrospectively calculated for each patient using all available International Classification of Disease 10th revision diagnostic codes. According to the aggregate score, patients were divided into two groups: the participants without frailty ( 5 points) and the participants with frailty ( 5 points). The primary outcome was death from any cause, and the secondary outcomes were cardiovascular death, ischemic stroke, major bleeding, and heart failure admission. With up to 7.2 1.5 years of follow-up, 11,953 participants (median age, 67 [interquartile range, 59.5-74.5] years; 7200 [60.2%] males) developed new-onset AF. Among the patients with AF, 3224 (26.9%) had frailty. Frailty was significantly associated with old age, female sex, polypharmacy, and other comorbidities. In patients with AF, frailty was negatively associated with OAC prescription after new-onset AF (p 0.001). Compared to patients without frailty, patients with frailty had a significantly higher incidence and risk of all-cause death (hazard ratio [HR] 2.88, 95% confidence interval [CI] 2.65-3.14), cardiovascular death (HR 2.42, 95% CI 2.10-2.80), ischemic stroke (HR 2.25, 95% CI 2.02-2.51), major bleeding (HR 2.44, 95% CI 2.17-2.73), and heart failure admission (HR 1.29, 95% CI 1.09-1.52). In subgroup analysis, when compared to the non-OAC group, the risks associated with frailty were significantly lower in the OAC group for all-cause death, cardiovascular death, ischemic stroke, and heart failure admission. Frailty was negatively associated with the use of OAC and was a predictor of poor prognosis owing to the association of frailty with death, thromboembolic events, bleeding, and heart failure admission. However, OAC use was associated with lower risks related to frailty for all-cause death and major adverse cardiovascular events in patients with AF.

Increased Incidence of Oral Cancer in Patients With Obstructive Sleep Apnea: Results From National Insurance Claims Data 2007–2014

Few studies have shown an increased risk of oral cancer in patients with obstructive sleep apnea syndrome (OSAS). We investigated the association between OSAS and oral cancer using data from the Korea National Health Insurance Service database. A total of 198574 male patients who were newly diagnosed with OSAS between 2007 and 2014 were included. A control group of 992870 participants was selected using propensity score matching, and the hazard ratio for oral cancer (95% confidence interval) was calculated. The incidence of oral cancer among patients with OSAS was significantly higher than that of the controls (1.25 [1.01–1.54]). Regarding oral cancer incidence by sex, there was no increase in the hazard ratio in males, but it increased to 2.29 (2.29 [1.38–3.70]) in females. In particular, the incidence of oral cancer was the highest in patients aged 40–65 years (1.38 [1.07–1.75]).

Risk of tuberculosis after endoscopic resection and gastrectomy in gastric cancer: nationwide population-based matched cohort study.

This study aimed to investigate the association between gastrectomy and endoscopic resection for gastric cancer and the subsequent tuberculosis incidence. We conducted a nationwide matched cohort study using data from the Korea National Health Insurance Service from 2013 to 2019. We created two cohorts: patients who underwent gastrectomy and those who had endoscopic resection. Each patient was matched 1:1 with an unexposed individual based on index year, age, sex, income, and various comorbidities. The primary outcome was the incidence of tuberculosis during the follow-up period. Our study comprised 90,886 gastrectomy patients and 46,759 endoscopic resection patients. The tuberculosis incidence was significantly higher in the gastrectomy group compared to its matched non-gastrectomy group (IRR 1.69, 95% CI 1.43-1.99, p < .001). In contrast, there was no significant difference in tuberculosis incidence between the endoscopic resection group and its matched non-resection group (IRR 0.95, 95% CI 0.75-1.19, p = 0.627). The Kaplan-Meier cumulative incidence also did not differ between the two groups. However, tuberculosis incidence significantly increased in the first year after endoscopic resection. Gastrectomy for gastric cancer is associated with a higher incidence of subsequent tuberculosis, while no significant association was observed for endoscopic resection. However, tuberculosis incidence increases significantly during the first year after endoscopic resection.

Cancer risks in patients with ankylosing spondylitis and the effects of biologic agents: a population-based study

Abstract Objective The objective of this study was to conduct a population-based analysis of the malignancy risks of patients with AS. Methods A total of 1796 patients with AS and 7184 age- and sex-matched controls (1:4 ratio) were selected from the Korea National Health Insurance Service–National Sample Cohort database. Data of patients diagnosed with AS (code M45) according to the International Classification of Diseases (ICD) 10th edition, between 2002 and 2019, were reviewed. These data were extracted based on the ICD codes assigned to cancer patients. Results Cancer developed in 168/1796 patients (9.3%) after the AS diagnosis. After adjusting for confounders, the cancer risk of patients with AS was not significantly increased compared with that of controls [adjusted hazard ratio (HR): 1.1; 95% CI: 0.93–1.31]. However, the risks for upper gastrointestinal (GI) cancer (adjusted HR: 1.51; 95% CI: 1.07–2.12) and haematologic malignancy (adjusted HR: 2.36; 95% CI: 1.2–4.65) were significantly higher in patients with AS than in controls. There were no significant differences in the risks for other major cancers between patients with AS and controls. Regarding medication for AS, the HR of upper GI cancer was higher in patients with AS compared with controls (adjusted HR: 1.51; 95% CI: 1.00–2.29). Conclusion The overall cancer risk in patients with AS was not significantly different compared with that in the controls. However, while the effect of NSAIDs on upper GI cancer cannot be ruled out, patients with AS exhibited a significant increase in the risk of both upper GI cancer and haematologic malignancy.

Abstract 15724: All-Cause Death and Major Adverse Events in Atrial Fibrillation With Frailty: Observations From the Korea National Health Insurance Service Data

Introduction: Atrial fibrillation (AF) may be a marker of frailty. Previous evidence indicated that frailty in patients with AF has been associated with increased adverse events. Hypothesis: This study aimed to investigate the effect of frailty on the use of oral anticoagulants (OAC) and clinical outcomes in a nationwide cohort of patients with AF. Methods: We included 451,368 participants without AF from the Korea National Health Insurance Service-Health Screening cohort from 2005 to 2010. Patients’ Hospital Frailty Risk Score was calculated and patients were divided into two groups: without frailty (&lt; 5 points) and with frailty (≥ 5 points). Results: Over 7.2 years, 11,953 participants (median age, 67 years; 60.2% men) developed new-onset AF. Among these patients, 26.9% had frailty. Frailty was significantly associated with older age, female sex, polypharmacy, and comorbidities. Frailty was negatively associated with OAC prescription after new-onset AF ( P &lt; 0.001). Patients with frailty had significantly higher risk of all-cause death (hazard ratio [HR] 2.87, 95% confidence interval [CI] 2.66-3.11), cardiovascular death (HR 2.60, 95% CI 2.77-2.98), stroke (HR 2.49, 95% CI 2.25-2.75), major bleeding (HR 2.54, 95% CI 2.28-2.83), and heart failure admission (HR 1.30, 95% CI 1.11-1.53). The increased risks of all-cause death, cardiovascular death, stroke, and heart failure admission due to frailty were lower with OAC prescription. Conclusions: Frailty was negatively associated with OAC use and was a predictor of worse prognosis. However, the increased risks associated with frailty were reduced by OAC in patients with AF.

Abstract 14572: Polypharmacy and Major Adverse Events in Atrial Fibrillation: Observations From the Korea National Health Insurance Service Data

Introduction: Previous evidence suggests that atrial fibrillation (AF) patients who receive polypharmacy are at an increased risk of experiencing adverse events. In this study, we investigated the prevalence of polypharmacy, identified risk factors associated with polypharmacy, and assessed the impact of polypharmacy on clinical outcomes in a ‘real-world’ data. Methods: We included 451,368 participants without AF (54[48.0-63.0] years; 207,748[46.0%] female) in the Korea National Health Insurance Service-Health Screening (NHIS-HealS) cohort from 2002 to 2013. All concomitant drugs were carefully collected and recorded. Polypharmacy was defined as the intake of ≥5 concomitant drugs. All-cause death, ischemic strokes/transient ischemic attacks (TIAs), major bleeding, heart failure admission were recorded. Results: With up to 7.7 (6.8-8.3) years of follow-up and 768,306 person-years, 12,241 incident AF cases occurred. Among included AF patients (40.0% females, 63.0[54.0-70.0] years), the prevalence of polypharmacy was 30.9 % (3,784). In new-onset AF, older age (per 10 increases, OR 1.32, 95% CI 1.26-1.40), hypertension (OR 4.00, 95 % CI 3.62-4.43), diabetes mellitus (OR 3.25, 95 % CI 2.86-3.70), COPD (OR 3.00, 95% CI 2.51-3.57), ischemic stroke/TIA (OR 2.36, 95% CI 2.03-2.73), dementia (OR 2.30, 95% CI 1.06-4.98), ESRD or CKD (OR 1.97, 95% CI 1.38-2.82), and heart failure (OR 1.95, 95% CI 1.69-2.26) were independently associated to the polypharmacy. Patients with polypharmacy showed significantly higher incidence and risk of major bleeding (aHR 1.26, 95% CI 1.12-1.41). All-cause mortality showed higher incidence, the risk was higher but not statistically significant (aHR 1.11, 95 % CI 0.99-1.24). The risks of stroke and heart failure admission were not changed by polypharmacy. Conclusions: In this “real world” nationwide AF cohort, polypharmacy was highly prevalent and conditioned worse prognosis due to its association with major bleeding events.

Prevalence of pre-existing lung diseases and their association with income level among patients with lung cancer: a nationwide population-based case-control study in South Korea

BackgroundThis study aimed to estimate the prevalence of pre-existing lung diseases in patients with lung cancer compared to people without lung cancer and examine the association between income levels and...

치매 노인의 인지 수준과 행동심리증상 간 관계에서 일상생활활동 의존도의 매개효과

Objective: The purpose of this study was to analyze the relationship between cognitive function, dependence on activity of daily life (ADL), and behavioral and psychological symptoms of dementia (BPSD) in older adults, and to investigate the mediating effect of ADL dependence. Methods: A secondary data analysis was conducted using 2015 data from an older adult cohort database (DB) provided by the Korea National Health Insurance Service. Those who received a diagnosis of dementia more than once between 2002 and 2015 and had a grade of 1 to 5 in terms of long-term care service were selected. In addition, a total of 12,363 data were used for analysis. Cognitive function, BPSD, and ADL dependence were extracted. A path model was established to analyze the relationship between the three major variables and the mediating effect of ADL dependence, and the direct effects of each path, the total effect, and indirect effects of the full model were calculated. Results: As a result of a path analysis, the effect between cognitive function and ADL dependence showed a value of .616 (p &lt; .0001), the effect between cognitive function and BPSD was .199 (p &lt; .0001), and the effect between ADL dependence and BPSD was .039 (p = .0005). The total effect of the path model of the three variables was .223 (p &lt; .0001), and the indirect effect was .024 (p = .0005). In addition, there was a partial mediating effect of ADL dependence. Conclusion: As a result of analyzing the mediating effect of ADL dependence through a path model, the ADL dependence partially mediated the effect of cognitive function on BPSD. These results suggest that a program promoting ADL function may be useful for alleviating the BPSD in people with dementia. It is hoped that this study will be used as a basis for the need and development of intervention programs.