Purpose: The aim of this study was to investigate the occurrence of dry eye syndrome (DES) in children under 18 years old before and during the COVID-19 pandemic using nationwide population-based cohort analysis. Methods: This study utilized the database provided by the Korea Disease Control and Prevention Agency and the Korean National Health Insurance Service. We used claims-based data for patients diagnosed with COVID-19 between October 8, 2020, and December 31, 2021, and those without a diagnosis of COVID-19. DES cases were defined as having at least one diagnosis of H0411 or H1621 based on the International Classification of Diseases, 10th Revision codes. The primary outcome was the evaluation of the hazard ratio for DES between the COVID-19 season and the non–COVID-19 season. Results: A total of 198,486 individuals from the COVID-19 season cohort and 211,828 individuals from the non–COVID-19 season cohort were included in the study. There were no differences in characteristics between the COVID-19 season cohort and the non–COVID-19 season cohort (all standardized mean difference, <0.1). The cumulative incidence of DES during the COVID-19 season was significantly higher than that during the non–COVID-19 season. The COVID-19 season DES incidence rate was 6,419.64 per 100,000 person-years and non–COVID-19 season DES incidence rate was 5,804.88 per 100,000 person-years. In addition, children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Conclusions The prevalence of diagnosed DES in children increased during the COVID-19 pandemic compared to previous years. Children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Further studies are needed to directly analyze the potential factors associated with the increased prevalence of DES.

Purpose: The aim of this study was to investigate the occurrence of dry eye syndrome (DES) in children under 18 years old before and during the COVID-19 pandemic using nationwide population-based cohort analysis. Methods: This study utilized the database provided by the Korea Disease Control and Prevention Agency and the Korean National Health Insurance Service. We used claims-based data for patients diagnosed with COVID-19 between October 8, 2020, and December 31, 2021, and those without a diagnosis of COVID-19. DES cases were defined as having at least one diagnosis of H0411 or H1621 based on the International Classification of Diseases, 10th Revision codes. The primary outcome was the evaluation of the hazard ratio for DES between the COVID-19 season and the non–COVID-19 season. Results: A total of 198,486 individuals from the COVID-19 season cohort and 211,828 individuals from the non–COVID-19 season cohort were included in the study. There were no differences in characteristics between the COVID-19 season cohort and the non–COVID-19 season cohort (all standardized mean difference, <0.1). The cumulative incidence of DES during the COVID-19 season was significantly higher than that during the non–COVID-19 season. The COVID-19 season DES incidence rate was 6,419.64 per 100,000 person-years and non–COVID-19 season DES incidence rate was 5,804.88 per 100,000 person-years. In addition, children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Conclusions The prevalence of diagnosed DES in children increased during the COVID-19 pandemic compared to previous years. Children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Further studies are needed to directly analyze the potential factors associated with the increased prevalence of DES.

Purpose: The aim of this study was to investigate the occurrence of dry eye syndrome (DES) in children under 18 years old before and during the COVID-19 pandemic using nationwide population-based cohort analysis. Methods: This study utilized the database provided by the Korea Disease Control and Prevention Agency and the Korean National Health Insurance Service. We used claims-based data for patients diagnosed with COVID-19 between October 8, 2020, and December 31, 2021, and those without a diagnosis of COVID-19. DES cases were defined as having at least one diagnosis of H0411 or H1621 based on the International Classification of Diseases, 10th Revision codes. The primary outcome was the evaluation of the hazard ratio for DES between the COVID-19 season and the non–COVID-19 season. Results: A total of 198,486 individuals from the COVID-19 season cohort and 211,828 individuals from the non–COVID-19 season cohort were included in the study. There were no differences in characteristics between the COVID-19 season cohort and the non–COVID-19 season cohort (all standardized mean difference, <0.1). The cumulative incidence of DES during the COVID-19 season was significantly higher than that during the non–COVID-19 season. The COVID-19 season DES incidence rate was 6,419.64 per 100,000 person-years and non–COVID-19 season DES incidence rate was 5,804.88 per 100,000 person-years. In addition, children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Conclusions The prevalence of diagnosed DES in children increased during the COVID-19 pandemic compared to previous years. Children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Further studies are needed to directly analyze the potential factors associated with the increased prevalence of DES.

Purpose: The aim of this study was to investigate the occurrence of dry eye syndrome (DES) in children under 18 years old before and during the COVID-19 pandemic using nationwide population-based cohort analysis. Methods: This study utilized the database provided by the Korea Disease Control and Prevention Agency and the Korean National Health Insurance Service. We used claims-based data for patients diagnosed with COVID-19 between October 8, 2020, and December 31, 2021, and those without a diagnosis of COVID-19. DES cases were defined as having at least one diagnosis of H0411 or H1621 based on the International Classification of Diseases, 10th Revision codes. The primary outcome was the evaluation of the hazard ratio for DES between the COVID-19 season and the non–COVID-19 season. Results: A total of 198,486 individuals from the COVID-19 season cohort and 211,828 individuals from the non–COVID-19 season cohort were included in the study. There were no differences in characteristics between the COVID-19 season cohort and the non–COVID-19 season cohort (all standardized mean difference, <0.1). The cumulative incidence of DES during the COVID-19 season was significantly higher than that during the non–COVID-19 season. The COVID-19 season DES incidence rate was 6,419.64 per 100,000 person-years and non–COVID-19 season DES incidence rate was 5,804.88 per 100,000 person-years. In addition, children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Conclusions The prevalence of diagnosed DES in children increased during the COVID-19 pandemic compared to previous years. Children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Further studies are needed to directly analyze the potential factors associated with the increased prevalence of DES.

Purpose: The aim of this study was to investigate the occurrence of dry eye syndrome (DES) in children under 18 years old before and during the COVID-19 pandemic using nationwide population-based cohort analysis. Methods: This study utilized the database provided by the Korea Disease Control and Prevention Agency and the Korean National Health Insurance Service. We used claims-based data for patients diagnosed with COVID-19 between October 8, 2020, and December 31, 2021, and those without a diagnosis of COVID-19. DES cases were defined as having at least one diagnosis of H0411 or H1621 based on the International Classification of Diseases, 10th Revision codes. The primary outcome was the evaluation of the hazard ratio for DES between the COVID-19 season and the non–COVID-19 season. Results: A total of 198,486 individuals from the COVID-19 season cohort and 211,828 individuals from the non–COVID-19 season cohort were included in the study. There were no differences in characteristics between the COVID-19 season cohort and the non–COVID-19 season cohort (all standardized mean difference, <0.1). The cumulative incidence of DES during the COVID-19 season was significantly higher than that during the non–COVID-19 season. The COVID-19 season DES incidence rate was 6,419.64 per 100,000 person-years and non–COVID-19 season DES incidence rate was 5,804.88 per 100,000 person-years. In addition, children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Conclusions The prevalence of diagnosed DES in children increased during the COVID-19 pandemic compared to previous years. Children aged 13 to 18 years, female sex, those living in metropolitan areas, and those with diabetes mellitus had a higher risk of DES. Further studies are needed to directly analyze the potential factors associated with the increased prevalence of DES.

Background/Aims: Chronic hepatitis B (CHB) is related to an increased risk of extrahepatic malignancy (EHM), and antiviral treatment is associated with an incidence of EHM comparable to controls. We compared the risks of EHM and intrahepatic malignancy (IHM) between entecavir (ETV) and tenofovir disoproxil fumarate (TDF) treatment. Methods: Using data from the National Health Insurance Service of Korea, this nationwide cohort study included treatment-naïve CHB patients who initiated ETV (n=24,287) or TDF (n=29,199) therapy between 2012 and 2014. The primary outcome was the development of any primary EHM. Secondary outcomes included overall IHM development. E-value was calculated to assess the robustness of results to unmeasured confounders. Results: The median follow-up duration was 5.9 years, and all baseline characteristics were well balanced after propensity score matching. EHM incidence rate differed significantly between within versus beyond 3 years in both groups (P<0.01, Davies test). During the first 3 years, EHM risk was comparable in the propensity score-matched cohort (5.88 versus 5.84/1,000 person-years; subdistribution hazard ratio [SHR]=1.01, 95% confidence interval [CI]=0.88–1.17, P=0.84). After year 3, however, TDF was associated with a significantly lower EHM incidence compared to ETV (4.92 versus 6.91/1,000 person-years; SHR=0.70, 95% CI=0.60–0.81, P<0.01; E-value for SHR=2.21). Regarding IHM, the superiority of TDF over ETV was maintained both within (17.58 versus 20.19/1,000 person-years; SHR=0.88, 95% CI=0.81–0.95, P<0.01) and after year 3 (11.45 versus 16.20/1,000 person-years; SHR=0.68, 95% CI=0.62–0.75, P<0.01; E-value for SHR=2.30). Conclusions TDF was associated with approximately 30% lower risks of both EHM and IHM than ETV in CHB patients after 3 years of antiviral therapy.

Background/Aims: Transarterial radioembolization (TARE) has shown promising results in treating advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT). However, whether TARE can provide superior or comparable outcomes to tyrosine kinase inhibitor (TKI) in patients with HCC and PVTT remains unclear. We compared the outcomes of TARE and TKI therapy in treatment-naïve patients with locally advanced HCC and segmental or lobar PVTT. Methods: This multicenter study included 216 patients initially treated with TARE (n=124) or TKI (sorafenib or lenvatinib; n=92) between 2011 and 2021. Baseline characteristics were balanced using propensity score matching (PSM) or inverse probability of treatment weighting (IPTW). The primary outcome was overall survival (OS). The secondary outcomes included progression-free survival (PFS) and objective response rate (ORR). Results: In the unmatched cohort, the median OS of the TARE and TKI groups were 28.2 and 7.2 months, respectively (p<0.001), and the TARE group experienced significantly and independently longer OS compared to the TKI group (adjusted hazard ratio=0.41, 95% confidence interval=0.28–0.60, p<0.001). Similar results were observed in the study cohorts balanced with IPTW (p=0.003) or PSM (p=0.004). Although PFS was comparable between the two groups, the TARE group showed a trend of prolonged PFS in a subpopulation of patients with Vp1 or Vp2 PVTT (p=0.052). In the matched cohorts, the ORR of the TARE group was 53.0–56.7%, whereas that of the TKI group was 12.3–15.0%. Conclusions For patients with advanced HCC with segmental or lobar PVTT and well-preserved liver function, TARE may provide superior OS compared to sorafenib or lenvatinib.

Background: To report the clinical manifestations of non-arteritic anterior ischemic optic neuropathy (NAION) cases after coronavirus disease 2019 (COVID-19) vaccination in Korea. Methods: This multicenter retrospective study included patients diagnosed with NAION within 42 days of COVID-19 vaccination. We collected data on vaccinations, demographic features, presence of vascular risk factors, ocular findings, and visual outcomes of patients with NAION. Results: The study included 16 eyes of 14 patients (6 men, 8 women) with a mean age of 63.5 ± 9.1 (range, 43–77) years. The most common underlying disease was hypertension, accounting for 28.6% of patients with NAION. Seven patients (50.0%) had no vascular risk factors for NAION. The mean time from vaccination to onset was 13.8 ± 14.2 (range, 1–41) days. All 16 eyes had disc swelling at initial presentation, and 3 of them (18.8%) had peripapillary intraretinal and/or subretinal fluid with severe disc swelling. Peripapillary hemorrhage was found in 50% of the patients, and one (6.3%) patient had peripapillary cotton-wool spots. In eight fellow eyes for which we were able to review the fundus photographs, the horizontal cup/ disc ratio was less than 0.25 in four eyes (50.0%). The mean visual acuity was logMAR 0.6 ± 0.7 at the initial presentation and logMAR 0.7 ± 0.8 at the final visit. Conclusion Only 64% of patients with NAION after COVID-19 vaccination have known vascular and ocular risk factors relevant to ischemic optic neuropathy. This suggests that COVID-19 vaccination may increase the risk of NAION. However, overall clinical features and visual outcomes of the NAION patients after COVID-19 vaccination were similar to those of typical NAION.

Background/Aims: The use of a self-expandable metal stent (SEMS) is recommended for unresectable malignant biliary obstruction (MBO). Stent-related adverse events might differ according to the position of the stent through the ampulla of Vater (AOV). We retrospectively evaluated SEMS patency and adverse events according to the position of the SEMS. Methods: In total, 280 patients who underwent endoscopic SEMS placement due to malignant distal biliary obstruction were analyzed retrospectively. Suprapapillary and transpapillary SEMS insertions were performed on 51 patients and 229 patients, respectively. Results: Between the suprapapillary group (SPG) and transpapillary group (TPG), the stent patency period was not significantly different (median [95% confidence interval]: 107 days [82.3 to 131.7] vs 120 days [99.3 to 140.7], p=0.559). There was also no significant difference in the rate of adverse events. In subgroup analysis, the stent patency for an MBO located within 2 cm from the AOV was found to be significantly shorter than that for an MBO located more than 2 cm from the AOV in the SPG (64 days [0 to 160.4] vs 127 days [82.0 to 171.9], p<0.001) and TPG (87 days [52.5 to 121.5] vs 130 [97.0 to 162.9], p<0.001). Patients with an MBO located within 2 cm from the AOV in both groups had a higher percentage of duodenal invasion (SPG: 40.0% vs 4.9%, p=0.002; TPG: 28.6% vs 2.9%, p<0.001) than patients with an MBO located more than 2 cm from the AOV. Conclusions The SPG and TPG showed similar results in terms of stent patency and rate of adverse events. However, patients with an MBO located within 2 cm from the AOV had a higher percentage of duodenal invasion with shorter stent patency than those with an MBO located more than 2 cm from the AOV, regardless of stent position.

Background: Large-scale studies about epidemiologic characteristics of renal infarction (RI) are few. In this study, we aimed to analyze the incidence and prevalence of RI with comorbidities in the South Korean population. Methods: We investigated the medical history of the entire South Korean adult population between 2013 and 2019 using the National Health Insurance Service database (n = 51,849,591 in 2019). Diagnosis of RI comorbidities were confirmed with International Classification of Disease, Tenth Revision, Clinical Modification codes. Epidemiologic characteristics, distribution of comorbidities according to etiologic mechanisms, and trend of antithrombotic agents were estimated. Results: During the 7-years, 10,496 patients were newly diagnosed with RI. The incidence rate increased from 2.68 to 3.06 per 100,000 person-years during the study period.The incidence rate of RI increased with age peaking in the 70s with 1.41 times male predominance. The most common comorbidity was hypertension, followed by dyslipidemia and diabetes mellitus. Regarding etiologic risk factor distribution, high embolic risk group, renovascular disease group, and hypercoagulable state group accounted for 16.6%, 29.1%, and 13.7% on average, respectively. For the antithrombotic treatment of RI, the prescription of antiplatelet agent gradually decreased from 17.0% to 13.0% while that of anticoagulation agent was maintained around 35%. The proportion of non-vitamin K antagonist oral anticoagulants remarkably increased from only 1.4% to 17.6%. Conclusion Considering the progressively increasing incidence of RI and high prevalence of coexisting risk factors, constant efforts to raise awareness of the disease are necessary. The current epidemiologic investigation of RI would be the stepping-stone to establishing future studies about clinical outcomes and optimal treatment strategies.