Subtyping of Performance Trajectory During Medical School, Medical Internship, and the First Year of Residency in Training Physicians: A Longitudinal Cohort Study.

BACKGROUND: Developmental trajectories of clinical skills in training physicians vary among tasks and show interindividual differences. This study examined the predictors of medical internship performance and residency entrance and found subtypes of performance trajectory in training physicians. METHODS: This retrospective cohort study involved 888 training physicians who completed a medical internship between 2015 and 2019. After the internship, 627 physicians applied for residency training between 2016 and 2020. Finally, 160 of them completed their first-year residency in internal medicine, surgery, pediatrics, and psychiatry departments between 2016 and 2020. Pearson's correlation coefficients of internship performance and first year-residency performance (n = 160) were calculated. Latent profile analysis identified performance trajectory subtypes according to medical school grade point average (GPA), internship performance, English proficiency, and residency selection procedures. Multivariate logistic regression models of residency acceptance (n = 627) and performance in the top 30%/lower 10% in the first year of residency were also constructed. RESULTS: Medical internship performance showed a significant positive correlation with the medical school GPA (r = 0.194) and the written score for the medical licensing examination (r = 0.125). Higher scores in the interview (adjusted odds ratio [aOR], 2.57) and written examination (aOR, 1.45) of residency selection procedures and higher medical internship performance (aOR, 1.19) were associated with a higher chance of residency acceptance. The latent profile analyses identified three training physician subgroups: average performance, consistently high performance (top 30%), and adaptation to changes (lowest 10%). Higher scores in the interview for residency selection (aOR, 1.35) and lower scores for medical internship performance (aOR, 0.79) were associated with a higher chance of performing in the top 30% or lowest 10% in the first year of residency, respectively. CONCLUSION: Performance in the interview and medical internship predicted being among the top 30% and lowest 10% of performers in the first year of residency training, respectively. Individualized educational programs to enhance the prospect of trainees becoming high-functioning physicians are needed.

How to enhance students' learning in a patient-centered longitudinal integrated clerkship: factors associated with students' learning experiences.

PURPOSE: Longitudinal integrated clerkships (LICs) have been introduced in medical schools, as learning relationships with clinical faculty or peers are important components of medical education. The purpose of this study was to investigate the characteristics of student-faculty and student-student interactions in the LIC and to identify other factors related to whether students understood and acquired the program's main outcomes. METHODS: The study was conducted among the 149 third-year students who participated in the LIC in 2019. We divided the students into groups of eight. These groups were organized into corresponding discussion classes, during which students had discussions with clinical faculty members and peers and received feedback. Clinical faculty members and students were matched through an e-portfolio, where records were approved and feedback was given. A course evaluation questionnaire was completed and analysed. RESULTS: A total of 144 valid questionnaires were returned. Logistic regression analysis showed that relevant feedback in discussion classes (adjusted odds ratio [AOR], 5.071; p<0.001), frequency of e-portfolio feedback (AOR, 1.813; p=0.012), and motivation by e-portfolio feedback (AOR, 1.790; p=0.026) predicted a greater likelihood of understanding the continuity of the patient's medical experience. Relevant feedback from faculty members in discussion classes (AOR, 3.455; p<0.001) and frequency of e-portfolio feedback (AOR, 2.232; p<0.001) also predicted a greater likelihood of understanding the concept of patient-centered care. CONCLUSION: Student-faculty interactions, including relevant feedback in discusstion classes, frequency of e-portfolio feedback, and motivation by e-portfolio feedback were found to be important factors in the LIC program.

Association of 3-hydroxy-3-methylglutaryl-coenzyme A reductase gene polymorphism with obesity and lipid metabolism in children and adolescents with autism spectrum disorder.

The prevalence of obesity among children and adolescents with autism spectrum disorder (ASD) is higher than that among typically developing children and adolescents. However, very few studies have explored the genetic factors associated with obesity in children and adolescents with ASD. Thus, the aim of this study was to examine the associations between 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) gene polymorphisms and obesity among children and adolescents with ASD. The study participants consisted of 33 children and adolescents with ASD and 271 age- and sex-matched typically developing controls. We compared the metabolic traits (body mass index, blood pressure, triglyceride, high-density lipoprotein, and fasting glucose levels) between the ASD and control group. Furthermore, we assessed the genotypes of rs12654264 in the HMGCR gene within the participants with ASD, and compared metabolic traits among the different allele subgroups. The mean body mass index (BMI) and triglyceride level of the ASD group were significantly higher than those of the control group. Within the ASD group, the triglyceride level of participants with rs12654264-T alleles was significantly higher than that of participants with A-alleles. A pattern of increasing values in the BMI and fasting glucose was also observed in participants with T allele. This is the first study to show that obesity in children and adolescents with ASD is associated with the cholesterol synthesis pathway. Future studies are needed to further clarify the molecular mechanisms by which the HMGCR gene influences metabolic traits.

Impact of COVID-19 on Lifestyle, Personal Attitudes, and Mental Health Among Korean Medical Students: Network Analysis of Associated Patterns.

The current COVID-19 pandemic have affected our daily lifestyle, pressed us with fear of infection, and thereby changed life satisfaction and mental health. The current study investigated influencing cascade of changes during the COVID-19 among the lifestyle, personal attitudes, and life (dis)satisfaction for medical students, using network-based approaches. This cross-sectional survey used self-reports of 454 medical students during June and July of 2020. Depressive mood, anxiety, and intention to drop out of school were observed in 11.9, 18.5, and 38.3% of medical students, respectively. Directed acyclic graph that estimated directional propagation of the COVID-19 in medical students' daily lives initiated from the perception of unexpected event, propagated to nervous and stressed feeling, trouble relaxing, feeling like a failure, and were followed by trouble concentrating, feeling loss of control for situation, and fear of infecting colleagues. These six features were also principal mediators within the intra-individual covariance networks comprised of changed lifestyle, personal attitude, and mental health at COVID-19 pandemic. Psychosocial supports targeting nervousness, trouble relaxing and concentrating, fear of spreading infection to colleagues, feelings of a failure or loss of situational control are required for better mental health of medical students during the COVID-19 pandemic.

Erratum: Correction of Text and Table in the Article "Establishing a Patient-centered Longitudinal Integrated Clerkship: Early Results from a Single Institution".

This corrects the article on p. e419 in vol. 35, PMID: 33372421.

Increased GM-CSF-producing NCR- ILC3s and neutrophils in the intestinal mucosa exacerbate inflammatory bowel disease.

OBJECTIVES: Inflammatory bowel disease (IBD) is characterised by dysregulated mucosal immune responses associated with genetic, environmental and microbial factors. Recent therapies targeting key inflammatory mediators such as tumor necrosis factor (TNF)-α emphasise the importance of innate immunity in the development of IBD. METHODS: We examined the distribution of innate immune cells such as innate lymphoid cells (ILCs) and myeloid cells in the intestinal epithelium from children diagnosed as IBD and murine models of colitis induced by dextran sulphate sodium (DSS) or an anti-CD40 antibodies. RESULTS: We found an increased number of type 3 ILCs (ILC3s) that do not express the natural cytotoxicity receptor (NCR) and neutrophils, in both human IBD patients and colitis-induced mice. A co-culture experiment of neutrophils with NCR- ILC3s revealed that NCR- ILC3s stimulate neutrophils by producing granulocyte-macrophage colony-stimulating factor (GM-CSF). Furthermore, a blockade of GM-CSF could inhibit the development of IBD by inhibiting neutrophil activity. CONCLUSION: The NCR- ILC3: GM-CSF: neutrophil axis could contribute to the development of IBD.

Is it feasible and effective to provide faculty development programs online for clinical teachers?

PURPOSE: Seoul National University College of Medicine operates a faculty development program for clinical teachers at multiple affiliated teaching hospitals. In 2020, the program was moved online due to coronavirus disease 2019. The purpose of this study was to determine whether it is feasible and effective to provide faculty development programs online in terms of clinical teachers' participation and satisfaction in comparison with offline programs. METHODS: Clinical teachers participated in the clinical teaching methods programs offline in 2019 and online in 2020. We analyzed participation rate and satisfaction level. All surveys items were rated on a 5-point Likert scale. We also interviewed instructors about the advantages and drawbacks of the online program. RESULTS: The participation rate of the online program (89.5%) was significantly higher than that of the offline program (67.8%). The overall satisfaction level for the online program (4.37) was similar to that for the offline program (4.50). CONCLUSION: Faculty development programs online are feasible and effective in medical education. We need to design training content that fits online programs, consider various online training methods to reinforce the strengths of online programs, and support participants to make good use of these programs.

How medical education survives and evolves during COVID-19: Our experience and future direction.

BACKGROUND: Due to the outbreak of coronavirus disease 2019 (COVID-19), school openings were postponed worldwide as a way to stop its spread. Most classes are moving online, and this includes medical school classes. The authors present their experience of running such online classes with offline clinical clerkship under pandemic conditions, and also present data on student satisfaction, academic performance, and preference. METHODS: The medical school changed every first-year to fourth-year course to an online format except the clinical clerkship, clinical skills training, and basic laboratory classes such as anatomy lab sessions. Online courses were pre-recorded video lectures or live-streamed using video communication software. At the end of each course, students and professors were asked to report their satisfaction with the online course and comment on it. The authors also compared students' academic performance before and after the introduction of online courses. RESULTS: A total of 69.7% (318/456) of students and 35.2% (44/125) of professors answered the questionnaire. Students were generally satisfied with the online course and 62.2% of them preferred the online course to the offline course. The majority (84.3%) of the students wanted to maintain the online course after the end of COVID-19. In contrast, just 13.6% of professors preferred online lectures and half (52.3%) wanted to go back to the offline course. With the introduction of online classes, students' academic achievement did not change significantly in four subjects, but decreased in two subjects. CONCLUSIONS: The inevitable transformation of medical education caused by COVID-19 is still ongoing. As the safety of students and the training of competent physicians are the responsibilities of medical schools, further research into how future physicians will be educated is needed.

Establishing a Patient-centered Longitudinal Integrated Clerkship: Early Results from a Single Institution.

BACKGROUND: Longitudinal integrated clerkships (LICs) have been adopted by medical schools to overcome the limitations of traditional block clerkship rotations and to promote continuity of care. In 2018, Seoul National University College of Medicine introduced a patient-centered LIC program as part of a new curriculum in parallel with traditional block rotation clerkships. The purpose of this study was to present the patient-centered LIC program and to investigate its educational effects. METHODS: In 2018 and 2019, a total of 298 third-year medical students participated in the LIC program. We divided the students into groups of eight, which were organized into corresponding discussion classes. Throughout the academic year, students followed up patients by interviewing them at the hospital or reviewing their electric medical records. Discussion classes on set topics were held seven times per year with facilitators and clinical faculites. Students completed a course evaluation questionnaire at the end of the academic year. The questionnaire included 22 items measured on a 5-point scale and two open-ended questions asking about the benefits and limitations of the program. The items covered three domains: student experience, satisfaction, and self-assessment. Final reflective essays were collected as both student assessments and data for qualitative analysis. RESULTS: During the study period, the overall experience of the students improved. We increased the number of faculty members and patients and decreased the number of students in each discussion class. We also provided additional feedback through an e-portfolio. Students' satisfaction changed positively. Compared to the rotational clerkship, students answered that the LIC provided additional help in learning the two core competencies. During the first 2 years of the program, the percentage of students who answered that the program was more helpful than the rotational clerkship increased from 23.7% to 46.4% for continuity of care (P < 0.001), and from 20.5% to 50.7% for patient-centered care (P < 0.001). CONCLUSION: Our patient-centered LIC, in parallel with traditional block rotation clerkships, had a positive effect on students' experience of continuity of care and patient-centered care.

Development of a Prognostic Score to Predict Mortality in Patients With Pediatric Acute Liver Failure.

OBJECTIVES: This study aims to develop a new prognostic score based on changes in serial laboratory data from patients with pediatric acute liver failure (PALF). METHODS: We retrospectively reviewed data on 146 patients with PALF at the Seoul National University Children Hospital (SNUCH) and the Asan Medical Center (AMC). Daily morning laboratory records were obtained for up to 7 days after diagnosis of PALF: total bilirubin (TB) (mg/dL), international normalized ratio for prothrombin time (INR) at enrolment; peak TB, peak INR, peak ammonia (µmol/L); the difference between the peak TB and TB at enrollment (ie, Δpeak TB), the difference between the peak INR and INR at enrollment (ie, Δpeak INR), the maximum change in serial TB (ie, Δdaily TB), the maximum change in serial INR level (ie, Δdaily INR). We assigned nontransplanted patients in SNUCH and AMC to derivation and validation cohorts, respectively. RESULTS: Δpeak TB, Δdaily TB, Δpeak INR, and Δdaily INR were significantly higher in the nonsurvival group. We developed a new score that can predict mortality in nontransplanted patients (derivation cohort n = 42, validation cohort n = 33). PALF-Delta score (PALF-Ds) = [0.232 × Δpeak TB (mg/dL)] + [2.263 × Δdaily INR] + [0.013 × peak ammonia (µmol/L)] - 4.498. The score yielded AUC 0.918 in the derivation cohort (sensitivity 81%, specificity 91%) and AUC 0.947 in the validation cohort (sensitivity 100%, specificity 89%). CONCLUSION: A prognostic scoring system using the change of TB/INR may be useful for predicting mortality in patients with PALF.

Successful Treatment of a Korean Infant with Giant Cell Hepatitis with Autoimmune Hemolytic Anemia Using Rituximab.

Giant cell hepatitis with autoimmune hemolytic anemia (AHA) is a rare disease of infancy characterized by the presence of both Coombs-positive hemolytic anemia and progressive liver disease with giant cell transformation of hepatocytes. Here, we report a case involving a seven-month-old male infant who presented with AHA followed by cholestatic hepatitis. The clinical features included jaundice, pallor, and red urine. Physical examination showed generalized icterus and splenomegaly. The laboratory findings suggested warm-type AHA with cholestatic hepatitis. Liver biopsy revealed giant cell transformation of hepatocytes and moderate lobular inflammation. The patient was successfully treated with four doses of rituximab. Early relapse of hemolytic anemia and hepatitis was observed, which prompted the use of an additional salvage dose of rituximab. He is currently in clinical remission.

Endoscopic Management of Pancreaticopleural Fistula in a Child with Hereditary Pancreatitis.

Pancreaticopleural fistula (PPF) a fistulous connection between the pancreas and pleural space due to prolonged chronic pancreatitis (CP). PPF is a very rare complication which presents in 0.4% of chronic pancreatitis cases, especially among children. We report a case involving a 3-year-old boy who presented with pleural effusion caused by a PPF, a complication of hereditary pancreatitis, which was, for the first time in Korea, successfully managed with endoscopic treatment. Chest radiography and computed tomography showed massive pleural effusion. Percutaneous catheter drainage was performed. High amylase levels were observed in the pleural fluid and serum, suggesting PPF. The patient was managed with bowel rest and octreotide infusion. Endoscopic retrograde cholangiopancreatography revealed CP, and pleural effusion was successfully managed with stent placement. PRSS1 genetic screening revealed R122H mutation.

Use of Anti-TNF Alpha Blockers Can Reduce Operation Rate and Lead to Growth Gain in Pediatric Crohn's Disease.

PURPOSE: Pediatric Crohn's disease (CD) is directly related to growth and has a high probability of requiring surgical intervention(s); therefore, more active treatment for CD is required for children. This study investigated the impact of biologics on growth and disease course associated with surgery. METHODS: This was a retrospective cohort study involving patients diagnosed with CD at the Seoul National University Children's Hospital (Seoul, Korea) between January 2006 and October 2017. The aim was to determine the characteristics of pediatric patients with CD and whether biologics affected growth and the surgical disease course. RESULTS: Among patients who underwent surgery for CD, the mean number of operations per patient was 1.89. The mean time from initial diagnosis to surgery was 19.3 months. The most common procedure was fistulectomy (34%), followed by incision and drainage (25%). In all patients, the use of biologics increased the height (p=0.002) and body mass index (BMI) (p=0.005). Among patients who underwent surgery, height (p=0.004) and BMI (p=0.048) were increased in the group using biologics. Patients who used biologics exhibited a low operation rate only within 2 years after diagnosis, with no differences thereafter (p=0.027). CONCLUSION: Although biologics could not mitigate the operation rate in pediatric patients who underwent surgery for CD, biological therapy delayed disease progression within 2 years of disease onset. Additionally, biologics conferred growth and BMI benefits in this window period. Therefore, it may be helpful to use biologics for optimal growth in pediatric patients with a high probability of undergoing future surgery.

Association Between Vitamin D Deficiency and Suspected Nonalcoholic Fatty Liver Disease in an Adolescent Population.

PURPOSE: Vitamin D deficiency is a condition widespread throughout the world. Recent studies have suggested that vitamin D deficiency was associated with obesity and metabolic syndrome. The purpose of the study was to examine the relationship between vitamin D deficiency and nonalcoholic fatty liver disease (NAFLD) in adolescents. METHODS: The data were obtained from the Korean National Health and Nutrition Examination Survey from 2008-2014. A total of 3,878 adolescents were included in the study. Vitamin D deficiency was defined as a 25-hydroxyvitamin D concentration <20 ng/mL and suspected NAFLD was defined as an alanine transaminase concentration >30 U/L. RESULTS: Vitamin D deficiency was noted in 78.9% of the studied population. Age, body mass index, waist circumference, and blood pressure, glucose, cholesterol, and triglyceride levels were significantly higher in adolescents with suspected NAFLD than in adolescents without suspected NAFLD, while the mean vitamin D level was significantly lower in adolescents with suspected NAFLD. The multivariate-adjusted odds of suspected NAFLD were higher with increased age, male gender, obesity, and metabolic syndrome. Individuals with vitamin D deficiency were at higher risk of suspected NAFLD (odds ratio, 1.77; 95% confidence interval, 1.07-2.95) after adjusting for age, gender, obesity, and metabolic syndrome. CONCLUSION: Vitamin D deficiency was associated with suspected NAFLD, independent of obesity and metabolic syndrome, in adolescents.

Deliberate Practice as an Effective Remediation Strategy for Underperforming Medical Students Focused on Clinical Skills: a Prospective Longitudinal Study.

BACKGROUND: It is critical to develop remedial education for underperforming medical students, but little is known about how to create an effective remediation program. Deliberate practice (DP) is a structured and reflective activity that is designed to optimize performance. Here we applied the concept of DP to create remedial education to improve the clinical practices of medical students. We also analyzed the effectiveness of the remediation program. METHODS: Based on the expert performance approach of DP, we designed a 4-week remedial program for clinical performance that included feedback and reflection. There were 74 student participants in this program from 2014 to 2017. Their clinical performance was re-evaluated after completion, and changes in their clinical performance scores were analyzed. RESULTS: Students who completed the remediation program showed significant improvements in clinical performance scores (P < 0.001). Most students found the program to be instructive and helpful for improving their clinical performance. They reported that role play with peers was the most helpful for improving their skills. CONCLUSION: The DP-based remediation program improved the clinical performance of failing medical students. This remediation program should continue to be offered to underperforming students to ensure that medical school graduates are competent.

Prevalence and risk factors of elevated alanine aminotransferase among Korean adolescents: 2001-2014.

BACKGROUND: An elevated alanine aminotransferase (ALT) level is a surrogate marker of non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in adolescents. The majority of previous NAFLD studies in adolescents were performed in selected obese populations or had a cross-sectional design without a time-trend analysis. The purpose of this study was to estimate the prevalence and time trends of elevated ALT levels in a general adolescent population and to identify factors associated with ALT elevation. METHODS: We analysed data of adolescent participants (aged 10-18 years) from the Korean National Health and Nutrition Examination Survey 2001-2014, a representative sample of the general population in South Korea. Suspected NAFLD was defined as ALT elevation (> 30 U/L) without hepatitis B surface antigen. In all statistical analyses, sampling weight- and design-based data were used. RESULTS: ALT was elevated in 5.3% (standard error: 0.3%) of the study population of adolescent participants (N = 8455). No significant trends were found from 2001 to 2014 in the prevalence of elevated ALT among male and female adolescents. In multiple logistic regression analysis, elevated ALT was independently associated with sex (odds ratio [OR] male versus female 4.5; 95% CI, 3.3-6.2), obesity (OR 7.6; 95% CI, 5.3-11.0), and truncal obesity (OR 2.5; 95% CI, 1.8-3.5). Furthermore, male sex, obesity, truncal obesity and high household income level were associated with log-transformed ALT levels in multiple regression analysis. CONCLUSIONS: In Korean adolescents of both genders, the prevalence of elevated ALT levels was stable from 2001 to 2014. This study has revealed that sex, obesity, truncal obesity and household income level are associated with ALT elevation in adolescents.

Higher Morbidity of Monogenic Inflammatory Bowel Disease Compared to the Adolescent Onset Inflammatory Bowel Disease.

PURPOSE: Monogenic inflammatory bowel disease (IBD) patients do not respond to conventional therapy and are associated with a higher morbidity. We summarized the clinical characteristics of monogenic IBD patients and compared their clinical outcomes to that of non-monogenic IBD patients. METHODS: We performed a retrospective cohort study of all children <18 years old who were diagnosed with IBD between 2005 and 2016. A total of 230 children were enrolled. Monogenic IBD was defined as a presentation age less than 6 years old with confirmation of a genetic disorder. We subdivided the groups into monogenic IBD (n=18), non-monogenic very early-onset IBD (defined as patients with a presentation age <6 years old without a confirmed genetic disorder, n=12), non-monogenic IBD (defined as all patients under 18 years old excluding monogenic IBD, n=212), and severe IBD (defined as patients treated with an anti-tumor necrosis factor excluding monogenic IBD, n=92). We compared demographic data, initial pediatric Crohn disease activity index/pediatric ulcerative colitis activity index (PCDAI/PUCAI) score, frequency of hospitalizations, surgical experiences, and height and weight under 3rd percentile among the patients enrolled. RESULTS: The initial PCDAI/PUCAI score (p<0.05), incidence of surgery per year (p<0.05), and hospitalization per year (p<0.05) were higher in the monogenic IBD group than in the other IBD groups. Additionally, the proportion of children whose weight and height were less than the 3rd percentile (p<0.05 and p<0.05, respectively) was also higher in the monogenic IBD group. CONCLUSION: Monogenic IBD showed more severe clinical manifestations than the other groups.

A Multicenter Study of the Antiviral Efficacy of Entecavir Monotherapy Compared to Lamivudine Monotherapy in Children with Nucleos(t)ide-naïve Chronic Hepatitis B.

BACKGROUND: The aim of this study was to compare the long-term efficacy of entecavir (ETV) and lamivudine (LAM) therapy in children with chronic hepatitis B (CHB) who had not received nucleoside analogue treatment. METHODS: In this multicenter, retrospective study, we included pediatric CHB patients younger than 20 years who received ETV or LAM treatment for at least 12 months and had no concomitant diseases. All of the patients were followed up every 1 to 3 months. At each visit, the patients underwent clinical evaluation and biochemical testing. RESULTS: Eight (53.3%), 14 (93.3%), and 2 (15.4%) of the ETV-treated patients achieved virologic suppression, alanine aminotransferase (ALT) normalization and hepatitis B e antigen (HBeAg) seroconversion, respectively, at 1 year. In the ETV group, the cumulative rate of virologic suppression at 3 years was 91.7%, which was significantly higher than that in the LAM group (P < 0.001). The mean duration of treatment before virologic suppression was shorter in the ETV group than in the LAM group (P = 0.040). The cumulative rate of seroconversion in the ETV group at 3 years was 39.4%, which was not significantly different from that in the LAM group (P = 0.439). The ETV group showed lower cumulate rates of virologic breakthrough (33.3% at 6 years) and genotypic mutation than the LAM group (P = 0.033 and P = 0.011, respectively). CONCLUSION: ETV is superior to LAM in pediatric CHB treatment because of its higher virologic suppression rate and lower cumulative rates of virologic breakthrough and genotypic mutation.

An Outbreak of Measles in a University in Korea, 2014.

Measles has been declared eliminated from the Korea since 2006. In April 2014, a measles outbreak occurred at a University in Seoul. A total of 85 measles cases were identified. In order to estimate vaccine effectiveness of measles vaccine, we reviewed the vaccination records of the university students. The vaccine effectiveness of two doses of measles containing vaccine was 60.0% (95% CI, 38.2-74.1; P < 0.05). Transmission was interrupted after the introduction of outbreak-response immunization. The outbreak shows that pockets of under-immunity among college students may have facilitated the disease transmission despite the high 2-dose vaccination coverage in the community.

Effect of the Baseline Vitamin D Level on Growth Outcome in Pediatric Crohn Disease.

PURPOSE: Vitamin D deficiency is common in Crohn disease (CD). The aim of the study was to examine the prevalence of vitamin D deficiency and evaluate the association between vitamin D status and growth outcome in Korean pediatric CD patients. METHODS: In this retrospective study, 17 children younger than 18 years old diagnosed with CD were enrolled and their serum 25-hydroxy vitamin D (25[OH]D) was checked between 2011 and 2015. We categorized the patients into two groups, Group 1 and Group 2. Group 1 included patients with serum 25(OH)D levels below 10 ng/mL, and Group 2 was for patients with a 25(OH)D serum levels between 10 ng/mL and 30 ng/mL. The z-scores for height (Htz), weight (Wtz), and body mass index (BMIz) were measured at baseline, 6 months, and 12 months. RESULTS: The mean serum 25(OH)D levels of the total 65 CD patients and 17 enrolled patients were 15.64±6.9 ng/mL and 13.1±5.1 ng/mL, respectively. There was no correlation at the beginning of the study between vitamin D level and growth parameters (Htz, Wtz, BMIz) or other variables including laboratory data and Pediatric Crohn Disease Activity Index. The Htz, Wtz, and BMIz in Group 1 showed no significant improvement at 6 months and 12 months follow-up. In Group 2, Wtz and BMIz showed significant improvements sustained until 12 months of follow-up. Htz showed no significant improvement at 6 months but there was significant improvement at 12 months. CONCLUSION: It seems that baseline vitamin D status affects growth outcome in pediatric CD.