Objective: Using a nationally representative cohort of medical claims data in Korea, this study aimed to analyze the association between the use of various anti-rheumatic agents and the risk of acute myocardial infarction (AMI) in patients with rheumatoid arthritis (RA). Methods: This nested case-control study used the Korean Health Insurance Review and Assessment data of 35,133 patients newly diagnosed with RA between 2011 and 2020. Incident AMI patients were identified and matched at a 1:4 ratio with randomly selected controls. The usage of anti-rheumatic agents was measured from the date of RA diagnosis to the index date and stratified based on exposure time and duration. The risk of AMI associated with each anti-rheumatic agent was estimated using conditional logistic regression, adjusted for comorbidities and concomitant drug use. Results: Of the 35,133 patients with RA, 484 were diagnosed with AMI. In total, 484 AMI patients and 1,924 controls with newly diagnosed RA were included in the analysis. Current exposure and long-term exposure to glucocorticoids (adjusted odds ratio [aOR]: 2.301, 95% confidence interval [CI]: 1.741~3.041; aOR: 1.792, 95% CI: 1.378~2.330) and leflunomide (aOR: 1.525, 95% CI: 1.196~1.944; aOR: 1.740, 95% CI: 1.372~2.207) were associated with an increased risk of AMI. Conclusion The study demonstrates a significant association between the current and long-term use of glucocorticoids and leflunomide and an increased risk of AMI in patients with RA. These findings underscore the importance of careful consideration of cardiovascular risks when selecting anti-rheumatic agents for RA treatment.

Objective: Using a nationally representative cohort of medical claims data in Korea, this study aimed to analyze the association between the use of various anti-rheumatic agents and the risk of acute myocardial infarction (AMI) in patients with rheumatoid arthritis (RA). Methods: This nested case-control study used the Korean Health Insurance Review and Assessment data of 35,133 patients newly diagnosed with RA between 2011 and 2020. Incident AMI patients were identified and matched at a 1:4 ratio with randomly selected controls. The usage of anti-rheumatic agents was measured from the date of RA diagnosis to the index date and stratified based on exposure time and duration. The risk of AMI associated with each anti-rheumatic agent was estimated using conditional logistic regression, adjusted for comorbidities and concomitant drug use. Results: Of the 35,133 patients with RA, 484 were diagnosed with AMI. In total, 484 AMI patients and 1,924 controls with newly diagnosed RA were included in the analysis. Current exposure and long-term exposure to glucocorticoids (adjusted odds ratio [aOR]: 2.301, 95% confidence interval [CI]: 1.741~3.041; aOR: 1.792, 95% CI: 1.378~2.330) and leflunomide (aOR: 1.525, 95% CI: 1.196~1.944; aOR: 1.740, 95% CI: 1.372~2.207) were associated with an increased risk of AMI. Conclusion The study demonstrates a significant association between the current and long-term use of glucocorticoids and leflunomide and an increased risk of AMI in patients with RA. These findings underscore the importance of careful consideration of cardiovascular risks when selecting anti-rheumatic agents for RA treatment.

Objective: Using a nationally representative cohort of medical claims data in Korea, this study aimed to analyze the association between the use of various anti-rheumatic agents and the risk of acute myocardial infarction (AMI) in patients with rheumatoid arthritis (RA). Methods: This nested case-control study used the Korean Health Insurance Review and Assessment data of 35,133 patients newly diagnosed with RA between 2011 and 2020. Incident AMI patients were identified and matched at a 1:4 ratio with randomly selected controls. The usage of anti-rheumatic agents was measured from the date of RA diagnosis to the index date and stratified based on exposure time and duration. The risk of AMI associated with each anti-rheumatic agent was estimated using conditional logistic regression, adjusted for comorbidities and concomitant drug use. Results: Of the 35,133 patients with RA, 484 were diagnosed with AMI. In total, 484 AMI patients and 1,924 controls with newly diagnosed RA were included in the analysis. Current exposure and long-term exposure to glucocorticoids (adjusted odds ratio [aOR]: 2.301, 95% confidence interval [CI]: 1.741~3.041; aOR: 1.792, 95% CI: 1.378~2.330) and leflunomide (aOR: 1.525, 95% CI: 1.196~1.944; aOR: 1.740, 95% CI: 1.372~2.207) were associated with an increased risk of AMI. Conclusion The study demonstrates a significant association between the current and long-term use of glucocorticoids and leflunomide and an increased risk of AMI in patients with RA. These findings underscore the importance of careful consideration of cardiovascular risks when selecting anti-rheumatic agents for RA treatment.

Purpose: To identify the prevalence and risk factors of coronavirus disease 2019 (COVID-19) reinfection in patients with rheumatoid arthritis (RA). Materials and Methods: This study retrospectively analyzed patients with RA with a documented COVID-19 infection between January 2021 and December 2022 at a tertiary hospital in Seoul, South Korea. Reinfection was defined as a subsequent positive test result for severe acute respiratory syndrome coronavirus 2 at least 3 months after the initial infection. Cox proportional hazards models with backward elimination were employed to assess the association between potential risk factors and risk of reinfection. Results: Of 351 included patients with RA {female, 81.5%; median age, 58.0 years [interquartile range (IQR), 48.0–66.0]}, 252 (71.8%) were treated with methotrexate and 12 (3.4%) received leflunomide during the initial infection. Over a median follow-up of 1.5 (IQR, 1.1–1.6) years, 43 (12.3%) patients experienced reinfection, equating to an incidence rate of 8.97 per 100 patient-years.The median time interval between infections was 0.8 (IQR, 0.6–1.2) years. Among the risk factors, leflunomide use showed a significant association with reinfection (hazard ratio, 2.968; 95% confidence interval, 1.057–8.335; p=0.039). However, no significant changes occurred in disease activity following reinfection [disease activity score using 28 joints: baseline median, 2.3 (IQR, 1.9– 2.8); post-reinfection median, 2.3 (IQR, 1.8–2.6), p for change=0.895]. Conclusion In this retrospective cohort study of patients with RA with COVID-19 infection, approximately 12% of patients experienced reinfection without significant change in disease activity. Leflunomide use was associated with a higher risk of reinfection.

Purpose: To identify the prevalence and risk factors of coronavirus disease 2019 (COVID-19) reinfection in patients with rheumatoid arthritis (RA). Materials and Methods: This study retrospectively analyzed patients with RA with a documented COVID-19 infection between January 2021 and December 2022 at a tertiary hospital in Seoul, South Korea. Reinfection was defined as a subsequent positive test result for severe acute respiratory syndrome coronavirus 2 at least 3 months after the initial infection. Cox proportional hazards models with backward elimination were employed to assess the association between potential risk factors and risk of reinfection. Results: Of 351 included patients with RA {female, 81.5%; median age, 58.0 years [interquartile range (IQR), 48.0–66.0]}, 252 (71.8%) were treated with methotrexate and 12 (3.4%) received leflunomide during the initial infection. Over a median follow-up of 1.5 (IQR, 1.1–1.6) years, 43 (12.3%) patients experienced reinfection, equating to an incidence rate of 8.97 per 100 patient-years.The median time interval between infections was 0.8 (IQR, 0.6–1.2) years. Among the risk factors, leflunomide use showed a significant association with reinfection (hazard ratio, 2.968; 95% confidence interval, 1.057–8.335; p=0.039). However, no significant changes occurred in disease activity following reinfection [disease activity score using 28 joints: baseline median, 2.3 (IQR, 1.9– 2.8); post-reinfection median, 2.3 (IQR, 1.8–2.6), p for change=0.895]. Conclusion In this retrospective cohort study of patients with RA with COVID-19 infection, approximately 12% of patients experienced reinfection without significant change in disease activity. Leflunomide use was associated with a higher risk of reinfection.

Purpose: To identify the prevalence and risk factors of coronavirus disease 2019 (COVID-19) reinfection in patients with rheumatoid arthritis (RA). Materials and Methods: This study retrospectively analyzed patients with RA with a documented COVID-19 infection between January 2021 and December 2022 at a tertiary hospital in Seoul, South Korea. Reinfection was defined as a subsequent positive test result for severe acute respiratory syndrome coronavirus 2 at least 3 months after the initial infection. Cox proportional hazards models with backward elimination were employed to assess the association between potential risk factors and risk of reinfection. Results: Of 351 included patients with RA {female, 81.5%; median age, 58.0 years [interquartile range (IQR), 48.0–66.0]}, 252 (71.8%) were treated with methotrexate and 12 (3.4%) received leflunomide during the initial infection. Over a median follow-up of 1.5 (IQR, 1.1–1.6) years, 43 (12.3%) patients experienced reinfection, equating to an incidence rate of 8.97 per 100 patient-years.The median time interval between infections was 0.8 (IQR, 0.6–1.2) years. Among the risk factors, leflunomide use showed a significant association with reinfection (hazard ratio, 2.968; 95% confidence interval, 1.057–8.335; p=0.039). However, no significant changes occurred in disease activity following reinfection [disease activity score using 28 joints: baseline median, 2.3 (IQR, 1.9– 2.8); post-reinfection median, 2.3 (IQR, 1.8–2.6), p for change=0.895]. Conclusion In this retrospective cohort study of patients with RA with COVID-19 infection, approximately 12% of patients experienced reinfection without significant change in disease activity. Leflunomide use was associated with a higher risk of reinfection.

Purpose: To identify the prevalence and risk factors of coronavirus disease 2019 (COVID-19) reinfection in patients with rheumatoid arthritis (RA). Materials and Methods: This study retrospectively analyzed patients with RA with a documented COVID-19 infection between January 2021 and December 2022 at a tertiary hospital in Seoul, South Korea. Reinfection was defined as a subsequent positive test result for severe acute respiratory syndrome coronavirus 2 at least 3 months after the initial infection. Cox proportional hazards models with backward elimination were employed to assess the association between potential risk factors and risk of reinfection. Results: Of 351 included patients with RA {female, 81.5%; median age, 58.0 years [interquartile range (IQR), 48.0–66.0]}, 252 (71.8%) were treated with methotrexate and 12 (3.4%) received leflunomide during the initial infection. Over a median follow-up of 1.5 (IQR, 1.1–1.6) years, 43 (12.3%) patients experienced reinfection, equating to an incidence rate of 8.97 per 100 patient-years.The median time interval between infections was 0.8 (IQR, 0.6–1.2) years. Among the risk factors, leflunomide use showed a significant association with reinfection (hazard ratio, 2.968; 95% confidence interval, 1.057–8.335; p=0.039). However, no significant changes occurred in disease activity following reinfection [disease activity score using 28 joints: baseline median, 2.3 (IQR, 1.9– 2.8); post-reinfection median, 2.3 (IQR, 1.8–2.6), p for change=0.895]. Conclusion In this retrospective cohort study of patients with RA with COVID-19 infection, approximately 12% of patients experienced reinfection without significant change in disease activity. Leflunomide use was associated with a higher risk of reinfection.

Purpose: To identify the prevalence and risk factors of coronavirus disease 2019 (COVID-19) reinfection in patients with rheumatoid arthritis (RA). Materials and Methods: This study retrospectively analyzed patients with RA with a documented COVID-19 infection between January 2021 and December 2022 at a tertiary hospital in Seoul, South Korea. Reinfection was defined as a subsequent positive test result for severe acute respiratory syndrome coronavirus 2 at least 3 months after the initial infection. Cox proportional hazards models with backward elimination were employed to assess the association between potential risk factors and risk of reinfection. Results: Of 351 included patients with RA {female, 81.5%; median age, 58.0 years [interquartile range (IQR), 48.0–66.0]}, 252 (71.8%) were treated with methotrexate and 12 (3.4%) received leflunomide during the initial infection. Over a median follow-up of 1.5 (IQR, 1.1–1.6) years, 43 (12.3%) patients experienced reinfection, equating to an incidence rate of 8.97 per 100 patient-years.The median time interval between infections was 0.8 (IQR, 0.6–1.2) years. Among the risk factors, leflunomide use showed a significant association with reinfection (hazard ratio, 2.968; 95% confidence interval, 1.057–8.335; p=0.039). However, no significant changes occurred in disease activity following reinfection [disease activity score using 28 joints: baseline median, 2.3 (IQR, 1.9– 2.8); post-reinfection median, 2.3 (IQR, 1.8–2.6), p for change=0.895]. Conclusion In this retrospective cohort study of patients with RA with COVID-19 infection, approximately 12% of patients experienced reinfection without significant change in disease activity. Leflunomide use was associated with a higher risk of reinfection.

Background/Aims: Systemic lupus erythematosus (SLE) responder index (SRI)-4 response has been achieved with belimumab treatment in patients with moderate disease activity in cornerstone clinical trials and following studies. However, most studies involved patients treated with a mean prednisolone-equivalent dose of approximately 10 mg/d and focused on the steroid-sparing effect of belimumab. We aimed to identify the effect of belimumab in patients with mild-to-moderate SLE who were treated with low-dose or no corticosteroids. Methods: We retrospectively reviewed the electronic medical records of patients treated with belimumab for at least 6 months between May 2021 and June 2022. The primary endpoint was SRI-4 response at 6 months. Results: Thirty-one patients were included (13 low dose- and 18 steroid non-users). The mean age was 39.2 ± 11.4 years, and 90.3% of patients were female. The baseline Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) score was 6.0 (4.0–9.0). The primary endpoint was achieved in 32.3% (10/31) of patients. Significant improvements in anemia, C4 levels, and SELENA-SLEDAI score were observed during treatment. Univariate analysis showed that the baseline SELENA-SLEDAI and arthritis were significantly associated with SRI-4 response at 6 months, and only the SELENA-SLEDAI remained significant (p = 0.014) in multivariate analysis. Conclusions This cohort study is the first to report the efficacy of belimumab after minimizing the effect of corticosteroids. Belimumab showed efficacy in improving the SELENA-SLEDAI score, anemia, and low C4 in patients who did not receive corticosteroids or received only low doses.

Objective: Renal involvement in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can lead to severe renal dysfunction requiring dialysis at diagnosis. We aimed to study the clinical and pathologic characteristics of patients with AAV dependent on dialysis at presentation and the long-term renal outcomes of patients who recovered from dialysis. Methods: This retrospective study analyzed data of patients diagnosed with AAV who were on dialysis from July 2005 to May 2021 at a single tertiary center in Korea. Results: Thirty-four patients were included in the study (median age: 64.5 years, females: 61.8%), of which 13 discontinued and 21 continued dialysis. The proportion of normal glomeruli (p<0.001) and interstitial fibrosis (p=0.024) showed significant differences between both groups. Multivariable analysis showed that the proportion of normal glomeruli was associated with dialysis discontinuation (odds ratio=1.29, 95% confidence interval 0.99~1.68, p=0.063), although without statistical significance. Treatment modalities, including plasmapheresis, did not show significance with dialysis discontinuation. In the follow-up analysis of 13 patients who had discontinued dialysis for a median of 81 months, 12 did not require dialysis, and their glomerular filtration rate values significantly increased at follow-up time compared to when they stopped dialysis (37.5 [28.5~45.5] vs. 24.0 [18.5~30.0] mL/ min/1.73 m²; p=0.008). Conclusion Approximately 38% of AAV patients on dialysis discontinued dialysis, and the recovered patients had improved renal function without dialysis during longer follow-up. Patients with AAV on dialysis should be given the possibility of dialysis discontinuation and renal recovery, especially those with normal glomeruli in kidney pathology.