Background: Whether anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels post-third coronavirus disease (COVID-19) vaccination correlate with worse outcomes due to breakthrough infection is unclear. We evaluated the association between anti-SARS-CoV-2 antibody levels and symptomatic breakthrough infection or hospitalization during the Omicron surge in kidney transplant recipients. Methods: In total, 287 kidney transplant recipients expected to receive a third vaccination were enrolled between November 2021 and February 2022. The Abbott SARS-CoV-2 IgG II Quant test (Abbott, Chicago, IL, USA) was performed within three weeks before and four weeks after the third vaccination. The incidence of symptomatic breakthrough infection and hospitalization from two weeks to four months post-third vaccination was recorded. Results: After the third vaccination, the seropositive rate and median antibody titer of the 287 patients increased from 57.1% to 82.2% and from 71.7 (interquartile range [IQR] 7.2– 402.8) to 1,612.1 (IQR 153.9–5,489.1) AU/mL, respectively. Sixty-four (22.3%) patients had symptomatic breakthrough infections, of whom 12 required hospitalization. Lower anti-receptor-binding domain (RBD) IgG levels ( < 400 AU/mL) post-third vaccination were a risk factor for symptomatic breakthrough infection (hazard ratio [HR] = 3.46, P < 0.001).Anti-RBD IgG levels < 200 AU/mL were a critical risk factor for hospitalization (HR = 36.4, P = 0.007). Conclusions Low anti-spike IgG levels after third vaccination in kidney transplant recipients were associated with symptomatic breakthrough infection and, particularly, with hospitalization during the Omicron surge. These data can be used to identify patients requiring additional protective measures, such as passive immunization using monoclonal antibodies.

OBJECTIVES: In this study, we sought to evaluate the association between smoking status and subclinical coronary atherosclerosis, as detected by coronary computed tomography angiography (CCTA), in asymptomatic individuals. METHODS: We retrospectively analyzed 9,285 asymptomatic participants (mean age, 53.7±8.0 years; n=6,017, 64.8% male) with no history of coronary artery disease (CAD) who had undergone self-referred CCTA. Of these participants, 4,333 (46.7%) were considered never smokers, 2,885 (31.1%) former smokers, and 2,067 (22.3%) current smokers. We assessed the degree and characteristics of subclinical coronary atherosclerosis using CCTA, with obstructive CAD defined as a diameter stenosis of at least 50%. RESULTS: Compared with never-smokers, former smokers exhibited no significant differences in the probabilities of obstructive CAD, any coronary plaque, calcified plaque, or mixed plaque, as determined using adjusted odds ratios (aORs; p>0.05 for all). However, the risk of non-calcified plaque was significantly higher in former smokers (aOR, 1.34; 95% confidence interval [CI], 1.00 to 1.78; p=0.048). Current smokers had significantly higher rates of obstructive CAD (aOR, 1.46; 95% CI, 1.10 to 1.96; p=0.010), any coronary plaque (aOR, 1.41; 95% CI, 1.20 to 1.65; p<0.001), calcified plaque (aOR, 1.32; 95% CI, 1.13 to 1.55; p=0.001), non-calcified plaque (aOR, 1.72; 95% CI, 1.28 to 2.32; p<0.001), and mixed plaque (aOR, 2.00; 95% CI, 1.39 to 2.86; p<0.001) compared to never smokers. CONCLUSIONS This cross-sectional study revealed a significant association between current smoking and subclinical coronary atherosclerosis, as detected on CCTA. Additionally, former smoking demonstrated an association with non-calcified plaque, indicating elevated cardiovascular risk.

OBJECTIVES: In this study, we sought to evaluate the association between smoking status and subclinical coronary atherosclerosis, as detected by coronary computed tomography angiography (CCTA), in asymptomatic individuals. METHODS: We retrospectively analyzed 9,285 asymptomatic participants (mean age, 53.7±8.0 years; n=6,017, 64.8% male) with no history of coronary artery disease (CAD) who had undergone self-referred CCTA. Of these participants, 4,333 (46.7%) were considered never smokers, 2,885 (31.1%) former smokers, and 2,067 (22.3%) current smokers. We assessed the degree and characteristics of subclinical coronary atherosclerosis using CCTA, with obstructive CAD defined as a diameter stenosis of at least 50%. RESULTS: Compared with never-smokers, former smokers exhibited no significant differences in the probabilities of obstructive CAD, any coronary plaque, calcified plaque, or mixed plaque, as determined using adjusted odds ratios (aORs; p>0.05 for all). However, the risk of non-calcified plaque was significantly higher in former smokers (aOR, 1.34; 95% confidence interval [CI], 1.00 to 1.78; p=0.048). Current smokers had significantly higher rates of obstructive CAD (aOR, 1.46; 95% CI, 1.10 to 1.96; p=0.010), any coronary plaque (aOR, 1.41; 95% CI, 1.20 to 1.65; p<0.001), calcified plaque (aOR, 1.32; 95% CI, 1.13 to 1.55; p=0.001), non-calcified plaque (aOR, 1.72; 95% CI, 1.28 to 2.32; p<0.001), and mixed plaque (aOR, 2.00; 95% CI, 1.39 to 2.86; p<0.001) compared to never smokers. CONCLUSIONS This cross-sectional study revealed a significant association between current smoking and subclinical coronary atherosclerosis, as detected on CCTA. Additionally, former smoking demonstrated an association with non-calcified plaque, indicating elevated cardiovascular risk.

OBJECTIVES: In this study, we sought to evaluate the association between smoking status and subclinical coronary atherosclerosis, as detected by coronary computed tomography angiography (CCTA), in asymptomatic individuals. METHODS: We retrospectively analyzed 9,285 asymptomatic participants (mean age, 53.7±8.0 years; n=6,017, 64.8% male) with no history of coronary artery disease (CAD) who had undergone self-referred CCTA. Of these participants, 4,333 (46.7%) were considered never smokers, 2,885 (31.1%) former smokers, and 2,067 (22.3%) current smokers. We assessed the degree and characteristics of subclinical coronary atherosclerosis using CCTA, with obstructive CAD defined as a diameter stenosis of at least 50%. RESULTS: Compared with never-smokers, former smokers exhibited no significant differences in the probabilities of obstructive CAD, any coronary plaque, calcified plaque, or mixed plaque, as determined using adjusted odds ratios (aORs; p>0.05 for all). However, the risk of non-calcified plaque was significantly higher in former smokers (aOR, 1.34; 95% confidence interval [CI], 1.00 to 1.78; p=0.048). Current smokers had significantly higher rates of obstructive CAD (aOR, 1.46; 95% CI, 1.10 to 1.96; p=0.010), any coronary plaque (aOR, 1.41; 95% CI, 1.20 to 1.65; p<0.001), calcified plaque (aOR, 1.32; 95% CI, 1.13 to 1.55; p=0.001), non-calcified plaque (aOR, 1.72; 95% CI, 1.28 to 2.32; p<0.001), and mixed plaque (aOR, 2.00; 95% CI, 1.39 to 2.86; p<0.001) compared to never smokers. CONCLUSIONS This cross-sectional study revealed a significant association between current smoking and subclinical coronary atherosclerosis, as detected on CCTA. Additionally, former smoking demonstrated an association with non-calcified plaque, indicating elevated cardiovascular risk.

OBJECTIVES: In this study, we sought to evaluate the association between smoking status and subclinical coronary atherosclerosis, as detected by coronary computed tomography angiography (CCTA), in asymptomatic individuals. METHODS: We retrospectively analyzed 9,285 asymptomatic participants (mean age, 53.7±8.0 years; n=6,017, 64.8% male) with no history of coronary artery disease (CAD) who had undergone self-referred CCTA. Of these participants, 4,333 (46.7%) were considered never smokers, 2,885 (31.1%) former smokers, and 2,067 (22.3%) current smokers. We assessed the degree and characteristics of subclinical coronary atherosclerosis using CCTA, with obstructive CAD defined as a diameter stenosis of at least 50%. RESULTS: Compared with never-smokers, former smokers exhibited no significant differences in the probabilities of obstructive CAD, any coronary plaque, calcified plaque, or mixed plaque, as determined using adjusted odds ratios (aORs; p>0.05 for all). However, the risk of non-calcified plaque was significantly higher in former smokers (aOR, 1.34; 95% confidence interval [CI], 1.00 to 1.78; p=0.048). Current smokers had significantly higher rates of obstructive CAD (aOR, 1.46; 95% CI, 1.10 to 1.96; p=0.010), any coronary plaque (aOR, 1.41; 95% CI, 1.20 to 1.65; p<0.001), calcified plaque (aOR, 1.32; 95% CI, 1.13 to 1.55; p=0.001), non-calcified plaque (aOR, 1.72; 95% CI, 1.28 to 2.32; p<0.001), and mixed plaque (aOR, 2.00; 95% CI, 1.39 to 2.86; p<0.001) compared to never smokers. CONCLUSIONS This cross-sectional study revealed a significant association between current smoking and subclinical coronary atherosclerosis, as detected on CCTA. Additionally, former smoking demonstrated an association with non-calcified plaque, indicating elevated cardiovascular risk.

Complement component 3 glomerulonephritis (C3GN) is a rare kidney disease characterized by complement dysregulation that results in prominent complement component 3 (C3) deposition in the kidneys. The clinical course of C3GN varies from mild hematuria to progressive chronic kidney disease. In most patients, C3GN is driven by acquired factors, namely, autoantibodies that target C3 or C5 convertases. Genetic variations in complement-related genes are less frequent. We report the case of a 9-yearold Korean boy who presented with microscopic hematuria and a persistently low C3 level and had biopsy findings of C3GN, with the presence of a C3 gene mutation: a frameshift mutation associated with C3 deficiency. However, the patient did not exhibit any other symptoms of complement deficiency. Direct DNA sequencing of his family members revealed the same genetic mutation in his father and older brother. This case report is significant because there are very few such reports worldwide concerning gene mutations related to C3 deficiency to be discovered in patients with C3GN. Explaining C3GN pathogenesis is challenging; therefore, additional research is required in the future.

Purpose: Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (ARBs) are frequently employed to counteract the detrimental effects of proteinuria on glomerular diseases. However, the effects of ARBs remain poorly examined in pediatric patients with immunoglobulin A (IgA) nephropathy. Herein, we evaluated the efficacy and safety of losartan, an ARB, in pediatric IgA nephropathy with proteinuria. Methods: This prospective, single-arm, multicenter study included children with IgA nephropathy exhibiting proteinuria. Changes in proteinuria, blood pressure, and kidney function were prospectively evaluated before and 4 and 24 weeks after losartan administration. The primary endpoint was the difference in proteinuria between baseline and 24 weeks. Results: In total, 29 patients were enrolled and received losartan treatment. The full analysis set included 28 patients who received losartan at least once and had pre- and post-urinary protein to creatinine ratio measurements (n=28). The per-protocol analysis group included 22 patients who completed all scheduled visits without any serious violations during the study period. In both groups, the mean log (urine protein to creatinine ratio) value decreased significantly at 6 months. After 24 weeks, the urinary protein to creatinine ratio decreased by more than 50% in approximately 40% of the patients. The glomerular filtration rate was not significantly altered during the observation period. Conclusions Losartan decreased proteinuria without decreasing kidney function in patients with IgA nephropathy over 24 weeks. Losartan could be safely employed to reduce proteinuria in this patient population. ClinicalTrials.gov trial registration (NCT0223277)

OBJECTIVES: We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS: In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS: In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Identifying genetic mutations in individuals with inherited cystic kidney disease is necessary for precise treatment. We aimed to elucidate the genetic characteristics of cystic kidney disease in the Korean population. Methods: We conducted a 3-year prospective, multicenter cohort study at eight hospitals from May 2019 to May 2022. Patients with more than three renal cysts were enrolled and classified into two categories, typical autosomal dominant polycystic kidney disease (ADPKD) and atypical PKD. We identified the clinical characteristics and performed a genetic analysis using a targeted gene panel. Results: A total of 725 adult patients were included in the study, of which 560 (77.2%) were diagnosed with typical ADPKD and 165 (22.8%) had atypical PKD. Among the typical ADPKD cases, the Mayo imaging classification was as follows: 1A (55, 9.9%), 1B (149, 26.6%), 1C (198, 35.8%), 1D (90, 16.3%), and 1E (61, 11.0%). The atypical PKD cases were classified as bilateral cystic with bilateral atrophic (31, 37.3%), lopsided (27, 32.5%), unilateral (nine, 10.8%), segmental (eight, 9.6%), bilateral cystic with unilateral atrophic (seven, 8.4%), and asymmetric (one, 1.2%). Pathogenic variants were found in 64.3% of the patients using the ciliopathy-related targeted gene panel. The typical ADPKD group demonstrated a higher discovery rate (62.3%) than the atypical PKD group (41.8%). Conclusion: We present a nationwide genetic cohort’s baseline clinical and genetic characteristics for Korean cystic kidney disease.

Objectives: This study analyzed the decline in quality of life according to age in the chronic disease patient group, quantified it as a quantitative index, and compared it by sex and chronic disease. Methods: In the 2017-2019 Korea National Health and Nutrition Examination Survey database, 11,473 adults aged 19 years or older, excluding cancer patients, were analyzed for age-specific changes in the EQ-5D Index by chronic disease. The decline in quality of life according to age in patients with chronic diseases was analyzed by linear regression analysis while controlling for general characteristics. Then, linear regression analysis was performed according to sex. Results: In the case of the control group, the quality of life decreased by 0.0004 for every 1-year increase in age(P<0.001). By chronic disease, asthma(β=0.0019, P<0.001), arthritis(β=0.0017, P=0.002), thyroid disease(β=0.0016, P=0.015), dyslipidemia(β=0.0011, P=0.020), and hypertension(β=0.0009, P=0.027) mostly showed a greater decrease in quality of life than the control group. In addition, when divided into two groups by sex, hypertension(β=0.0012, P=0.029), thyroid disease(β=0.0041, P=0.038), and arthritis(β=0.0022, P<0.001) showed a significant decrease in quality of life only in male. Diabetes(β=0.0056, P=0.038), dyslipidemia(β=0.0022, P=0.001) significantly decreased quality of life only in female. Conclusions Chronic disease had a negative impact on patients perception of quality of life, and the more severe the pain and activity limitation due to the chronic disease, the more severe it was. It also showed different patterns according to sex. Therefore, it is necessary to allocate more medical resources and provide policy support to prevent chronic diseases, which are serious social problems.