Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: We aimed to investigate the characteristics of pediatric ulcerative colitis (UC) at diagnosis in Korea. Methods: This was a multicenter, registry-based, inception cohort study conducted in Korea between 2021 and 2023. Children and adolescents newly diagnosed with UC < 18 years were included. Baseline clinicodemographics, results from laboratory, endoscopic exams, and Paris classification factors were collected, and associations between factors at diagnosis were investigated. Results: A total 205 patients with UC were included. Male-to-female ratio was 1.59:1, and the median age at diagnosis was 14.7 years (interquartile range 11.9–16.2). Disease extent of E1 comprised 12.2% (25/205), E2 24.9% (51/205), E3 11.2% (23/205), and E4 51.7% (106/205) of the patients. S1 comprised 13.7% (28/205) of the patients. The proportion of patients with a disease severity of S1 was significantly higher in patients with E4 compared to the other groups (E1: 0% vs. E2: 2% vs. E3: 0% vs. E4: 24.5%, P < 0.001). Significant differences between disease extent groups were also observed in Pediatric Ulcerative Colitis Activity Index (median 25 vs. 35 vs. 40 vs. 45, respectively, P < 0.001), hemoglobin (median 13.5 vs.13.2 vs. 11.6 vs. 11.4 g/dL, respectively, P < 0.001), platelet count (median 301 vs. 324 vs. 372 vs. 377 × 103 /μL, respectively, P = 0.001), C-reactive protein (median 0.05 vs. 0.10 vs. 0.17 vs. 0.38 mg/dL, respectively, P < 0.001), and Ulcerative Colitis Endoscopic Index of Severity (median 4 vs. 4 vs. 4 vs. 5, respectively, P = 0.006). No significant differences were observed in factors between groups divided according to sex and diagnosis age. Conclusion This study represents the largest multicenter pediatric inflammatory bowel disease cohort in Korea. Disease severity was associated with disease extent in pediatric patients with UC at diagnosis.

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients.The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold.Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cellmediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Background: Self-sampling procedures to detect severe acute respiratory syndrome coronavirus 2 is important for patients who have difficulty visiting the hospital and may decrease the burden for health care workers (HCWs). The objective of this study was to evaluate the diagnostic performance, stability and usability of self-collected nasal and oral combo swabs and saliva specimens. Materials and Methods: We conducted a case-control study with 50 patients with coronavirus disease 2019 (COVID-19) and 50 healthy volunteers from March, 2021 to June, 2021. We performed real-time reverse-transcription polymerase chain reaction to compare the diagnostic performance of self-collected specimens using positive percent agreements (PPAs). Results: The PPAs between self-collected and HCW-collected specimens were 77.3 - 81.0% and 80.5 -86.7% for the combo swabs and saliva specimens, respectively. The PPAs increased to 88.9 - 89.2% and 81.2 - 82.1% with a cycle threshold value ≤30. Conclusion The diagnostic performance of self sampling was comparable to that of HCW sampling in patients with high viral loads and may thus assist in the early diagnosis of COVID-19.