Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Background/Aims: Fecal microbiota transplantation (FMT) is a promising therapy for inducing and maintaining remission in patients with ulcerative colitis (UC). However, FMT has not been approved for UC treatment in Korea. Our study aimed to investigate patient perceptions of FMT under the national medical policy. Methods: This was a prospective, multicenter study. Patients with UC ≥ 19 years of age were included. Patients were surveyed using 22 questions on FMT. Changes in perceptions of FMT before and after education were also compared. Results: A total of 210 patients with UC were enrolled. We found that 51.4% of the patients were unaware that FMT was an alternative treatment option for UC. After reading the educational materials on FMT, more patients were willing to undergo this procedure (27.1% vs. 46.7%; p < 0.001). The preferred fecal donor was the one recommended by a physician (41.0%), and the preferred transplantation method was the oral capsule (30.4%). A large proportion of patients (50.0%) reported that the national medical policy influenced their choice of FMT treatment. When patients felt severe disease activity, their willingness to undergo FMT increased (92.3% vs. 43.1%; p = 0.001). Conclusions Education can increase preference for FMT in patients with UC. When patients have severe disease symptoms or their quality of life decreases their willingness to undergo FMT increases. Moreover, national medical policies may influence patient choices regarding FMT.

The omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to have high infectivity and is more likely to evade vaccine immunity. However, booster vaccination is expected to strengthen cross-reactive immunity, thereby increasing the vaccine effectiveness (VE). This study aimed to evaluate the relative VE of the 3-dose (booster) vaccination compared with the 2-dose primary series vaccination in healthcare workers during omicron variant-dominant periods. During the omicron-dominant period from February 1, 2022 to February 28, 2022, a 1:1 matched case-control study was conducted.Healthcare workers with positive SARS-CoV-2 test results were classified as positive cases, whereas those with negative results served as controls. Compared with the 2-dose primary series vaccination, booster vaccination with mRNA vaccine showed moderate VE (53.1%).However, in multivariate analysis including the time elapsed after vaccination, the significant VE disappeared, reflecting the impact of recent vaccination rather than the third dose itself.

PURPOSE: It is controversial whether indoor pet exposure is either a risk or protective factor developing sensitization to pet allergens or asthma. Therefore, we investigated whether indoor pet ownership entails a risk for the development of asthma and sensitization in childhood. METHODS: The Panel Study of Korean Children (PSKC) is a general-population-based birth cohort study that recruited 2,078 mother-baby dyads in Korea between April and July of 2008. Among 1,577 children who were followed up in 2015, 559 underwent skin prick tests, spirometry and bronchial provocation tests using Provocholine. Having a cat or a dog and the prevalence of asthma were evaluated by using self-reported questionnaires and physicians’ medical records. RESULTS: During infancy, the rate of dog ownership was 4.5% (71 of 1,574) and that of cat ownership was 0.5% (8 of 1,574). Of the subjects, 7.9% (n=109) currently had at least 1 dog and 2.5% (n=34) had at least 1 cat. Pet ownership during infancy was associated with sensitization to cats or dogs (adjusted odds ratio [aOR], 4.24; 95% confidence interval [CI], 1.29–13.98), wheezing within 12 months (aOR, 5.56; 95% CI, 1.65–18.75) and current asthma (wheezing episode in the last 12 months+diagnosed asthma by physicians) (aOR, 6.36; 95% CI, 1.54–26.28). In contrast, pet ownership during the last 12 months was not associated with sensitization to cats or dogs or current asthma. CONCLUSION: Indoor pet exposure during infancy can be critical for developing sensitization to cats or dogs and asthma in childhood. Avoidance of pet exposure in early life may reduce sensitization to cats or dogs and development of asthma.
Allergens ; Animals ; Asthma ; Bronchial Provocation Tests ; Cats ; Child ; Cohort Studies ; Dogs ; Humans ; Infant ; Korea ; Medical Records ; Methacholine Chloride ; Odds Ratio ; Ownership ; Parturition ; Pets ; Prevalence ; Protective Factors ; Respiratory Sounds ; Risk Factors ; Skin ; Spirometry

BACKGROUND: Mitochondrial DNA (mtDNA) mutations may regulate the progression and chemosensitivity of leukemia. Few studies regarding mitochondrial aberrations and haplogroups in acute myeloid leukemia (AML) and their clinical impacts have been reported. Therefore, we focused on the mtDNA length heteroplasmies minisatellite instability (MSI), copy number alterations, and distribution of mitochondrial haplogroups in Korean patients with AML. METHODS: This study investigated 74 adult patients with AML and 70 controls to evaluate mtDNA sequence alterations, MSI, mtDNA copy number, haplogroups, and their clinical implications. The hypervariable (HV) control regions (HV1 and HV2), tRNA(leu1)gene, and cytochrome b gene of mtDNA were analyzed. Two mtDNA minisatellite markers, 16189 poly-C (¹⁶¹⁸⁴CCCCCTCCCC¹⁶¹⁹³, 5CT4C) and 303 poly-C (³⁰³CCCCCCCTCCCCC³¹⁵, 7CT5C), were used to examine the mtDNA MSI. RESULTS: In AML, most mtDNA sequence variants were single nucleotide substitutions, but there were no significant differences compared to those in controls. The number of mtMSI patterns increased in AML. The mean mtDNA copy number of AML patients increased approximately 9-fold compared to that of controls (P < 0.0001). Haplogroup D4 was found in AML with a higher frequency compared to that in controls (31.0% vs. 15.7%, P=0.046). None of the aforementioned factors showed significant impacts on the outcomes. CONCLUSION: AML cells disclosed more heterogeneous patterns with the mtMSI markers and had increased mtDNA copy numbers. These findings implicate mitochondrial genome instability in primary AML cells. Therefore, mtDNA haplogroup D4 might be associated with AML risk among Koreans.
Adult ; Cytochromes b ; DNA, Mitochondrial ; Genome, Mitochondrial* ; Humans ; Leukemia ; Leukemia, Myeloid, Acute* ; Minisatellite Repeats

BACKGROUND/AIMS: While surgical resection remains the standard of care in the treatment of upper urinary tract malignancies, nephrectomy is a risk factor for the development of chronic kidney disease (CKD). The aim of this study was to determine whether histologic evaluation of non-neoplastic kidney could enable early identification of unrecognized kidney disease and could be of prognostic value in predicting postoperative renal outcomes. METHODS: We retrospectively analyzed 51 patients with upper urinary tract malignancies who received uninephrectomy or uninephroureterectomy. A thorough pathologic evaluation of non-neoplastic kidney including special stains, immunofluorescence, and electron microscopic studies was performed. The degree of parenchymal changes was graded from 0 to 15. RESULTS: Of 51 patients, only 13 showed normal kidney pathology. Fifteen patients showed glomerular abnormalities, 14 showed diabetic nephropathy, and 11 showed vascular nephropathy. There was one case each of reflux nephropathy and chronic pyelonephritis. The median histologic score was 5 points. Only 25.4% of patients had ≤ 3 points. Score more than 5 was observed in 47.1% of patients. Postoperative estimated glomerular filtration rate (eGFR) at 3 to 36 months were obtained from 90.2% of patients, and of those, 34.8% had de novo CKD. Since no one had CKD in partial nephrectomized patients, we determined risk factors for CKD in radical nephrectomized patients. Cox regression analysis revealed that postoperative AKI, preoperative eGFR, and histologic score of non-neoplastic kidney were the independent predictors for CKD. CONCLUSIONS: We conclude that routine pathologic evaluation of non-neoplastic kidney provides valuable diagnostic and prognostic information.
Coloring Agents ; Diabetic Nephropathies ; Fluorescent Antibody Technique ; Glomerular Filtration Rate ; Humans ; Kidney Diseases ; Kidney Neoplasms ; Kidney* ; Nephrectomy ; Pathology ; Pyelonephritis ; Renal Insufficiency, Chronic ; Retrospective Studies ; Risk Factors ; Standard of Care ; Urinary Tract*

BACKGROUND/AIMS: An association between serum uric acid and cancer risk has been noted over the past few decades. There is ongoing debate about whether hyperuricemia represents an independent risk factor for colorectal neoplasm. We investigated the association between serum uric acid and prevalence of colorectal adenoma considering numerous confounding factors. METHODS: A cross-sectional study was performed with individuals who underwent a routine health check-up examination, including a screening colonoscopy and blood chemistry. The association between serum uric acid and prevalence of colorectal adenoma was estimated from the results of a logistic regression analysis. RESULTS: Of the 1,066 participants, 402 had colorectal adenoma (37.7%). In univariate models, the prevalence of colorectal adenoma was higher in participants in the fourth quartile uric acid level, compared to those in the first quartile uric acid level (OR, 1.67; 95% CI, 1.17-2.42; p=0.004). However, no significant association was detected between serum uric acid and prevalence of colorectal adenoma in multiple logistic regression analysis. A number of metabolic syndrome components exhibited a strong association with the prevalence of colorectal adenoma in the multivariate model (OR, 3.46 for highest vs. lowest; 95% CI, 1.30-9.20; p=0.021). Moreover, serum uric acid was strongly associated with metabolic syndrome-associated variables, including waist circumference, fasting blood glucose, systolic blood pressure, diastolic blood pressure, triglyceride, and high-density lipoprotein. CONCLUSIONS: Uric acid is not an independent risk factor for colorectal adenoma but is a risk indicator for metabolic syndrome-related colorectal adenoma.
Adenoma/*diagnosis/epidemiology/etiology ; Adult ; Asian Continental Ancestry Group ; Blood Glucose/analysis ; Blood Pressure ; Colonoscopy ; Colorectal Neoplasms/*diagnosis/epidemiology/etiology ; Cross-Sectional Studies ; Female ; Humans ; Logistic Models ; Male ; Metabolic Syndrome X/*diagnosis ; Middle Aged ; Odds Ratio ; Prevalence ; Republic of Korea ; Risk Factors ; Triglycerides/blood ; Uric Acid/*blood/urine ; Waist Circumference