1.Characteristics and Prevalence of Sequelae after COVID-19: A Longitudinal Cohort Study
Se Ju LEE ; Yae Jee BAEK ; Su Hwan LEE ; Jung Ho KIM ; Jin Young AHN ; Jooyun KIM ; Ji Hoon JEON ; Hyeri SEOK ; Won Suk CHOI ; Dae Won PARK ; Yunsang CHOI ; Kyoung-Ho SONG ; Eu Suk KIM ; Hong Bin KIM ; Jae-Hoon KO ; Kyong Ran PECK ; Jae-Phil CHOI ; Jun Hyoung KIM ; Hee-Sung KIM ; Hye Won JEONG ; Jun Yong CHOI
Infection and Chemotherapy 2025;57(1):72-80
Background:
The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments.
Materials and Methods:
We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19.
Results:
During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis.
Conclusion
Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.
2.Characteristics and Prevalence of Sequelae after COVID-19: A Longitudinal Cohort Study
Se Ju LEE ; Yae Jee BAEK ; Su Hwan LEE ; Jung Ho KIM ; Jin Young AHN ; Jooyun KIM ; Ji Hoon JEON ; Hyeri SEOK ; Won Suk CHOI ; Dae Won PARK ; Yunsang CHOI ; Kyoung-Ho SONG ; Eu Suk KIM ; Hong Bin KIM ; Jae-Hoon KO ; Kyong Ran PECK ; Jae-Phil CHOI ; Jun Hyoung KIM ; Hee-Sung KIM ; Hye Won JEONG ; Jun Yong CHOI
Infection and Chemotherapy 2025;57(1):72-80
Background:
The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments.
Materials and Methods:
We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19.
Results:
During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis.
Conclusion
Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.
3.Characteristics and Prevalence of Sequelae after COVID-19: A Longitudinal Cohort Study
Se Ju LEE ; Yae Jee BAEK ; Su Hwan LEE ; Jung Ho KIM ; Jin Young AHN ; Jooyun KIM ; Ji Hoon JEON ; Hyeri SEOK ; Won Suk CHOI ; Dae Won PARK ; Yunsang CHOI ; Kyoung-Ho SONG ; Eu Suk KIM ; Hong Bin KIM ; Jae-Hoon KO ; Kyong Ran PECK ; Jae-Phil CHOI ; Jun Hyoung KIM ; Hee-Sung KIM ; Hye Won JEONG ; Jun Yong CHOI
Infection and Chemotherapy 2025;57(1):72-80
Background:
The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments.
Materials and Methods:
We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19.
Results:
During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis.
Conclusion
Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.
4.Clinical Characteristics and Risk Factors for Mortality in Critical COVID-19 Patients Aged 50 Years or Younger During Omicron Wave in Korea:Comparison With Patients Older Than 50 Years of Age
Hye Jin SHI ; Jinyoung YANG ; Joong Sik EOM ; Jae-Hoon KO ; Kyong Ran PECK ; Uh Jin KIM ; Sook In JUNG ; Seulki KIM ; Hyeri SEOK ; Miri HYUN ; Hyun Ah KIM ; Bomi KIM ; Eun-Jeong JOO ; Hae Suk CHEONG ; Cheon Hoo JUN ; Yu Mi WI ; Jungok KIM ; Sungmin KYM ; Seungjin LIM ; Yoonseon PARK
Journal of Korean Medical Science 2023;38(28):e217-
Background:
The coronavirus disease 2019 (COVID-19) pandemic has caused the death of thousands of patients worldwide. Although age is known to be a risk factor for morbidity and mortality in COVID-19 patients, critical illness or death is occurring even in the younger age group as the epidemic spreads. In early 2022, omicron became the dominant variant of the COVID-19 virus in South Korea, and the epidemic proceeded on a large scale. Accordingly, this study aimed to determine whether young adults (aged ≤ 50 years) with critical COVID-19 infection during the omicron period had different characteristics from older patients and to determine the risk factors for mortality in this specific age group.
Methods:
We evaluated 213 critical adult patients (high flow nasal cannula or higher respiratory support) hospitalized for polymerase chain reaction-confirmed COVID-19 in nine hospitals in South Korea between February 1, 2022 and April 30, 2022. Demographic characteristics, including body mass index (BMI) and vaccination status; underlying diseases; clinical features and laboratory findings; clinical course; treatment received; and outcomes were collected from electronic medical records (EMRs) and analyzed according to age and mortality.
Results:
Overall, 71 critically ill patients aged ≤ 50 years were enrolled, and 142 critically ill patients aged over 50 years were selected through 1:2 matching based on the date of diagnosis. The most frequent underlying diseases among those aged ≤ 50 years were diabetes and hypertension, and all 14 patients who died had either a BMI ≥ 25 kg/m 2 or an underlying disease. The total case fatality rate among severe patients (S-CFR) was 31.0%, and the S-CFR differed according to age and was higher than that during the delta period. The S-CFR was 19.7% for those aged ≤ 50 years, 36.6% for those aged > 50 years, and 38.1% for those aged ≥ 65 years. In multivariate analysis, age (odds ratio [OR], 1.084; 95% confidence interval [CI], 1.043–1.127), initial low-density lipoprotein > 600 IU/L (OR, 4.782; 95% CI, 1.584–14.434), initial C-reactive protein > 8 mg/dL (OR, 2.940; 95% CI, 1.042–8.293), highest aspartate aminotransferase > 200 IU/L (OR, 12.931; 95% CI, 1.691–98.908), and mechanical ventilation implementation (OR, 3.671; 95% CI, 1.294–10.420) were significant independent predictors of mortality in critical COVID-19 patients during the omicron wave. A similar pattern was shown when analyzing the data by age group, but most had no statistical significance owing to the small number of deaths in the young critical group. Although the vaccination completion rate of all the patients (31.0%) was higher than that in the delta wave period (13.6%), it was still lower than that of the general population. Further, only 15 (21.1%) critically ill patients aged ≤ 50 years were fully vaccinated. Overall, the severity of hospitalized critical patients was significantly higher than that in the delta period, indicating that it was difficult to find common risk factors in the two periods only with a simple comparison.
Conclusion
Overall, the S-CFR of critically ill COVID-19 patients in the omicron period was higher than that in the delta period, especially in those aged ≤ 50 years. All of the patients who died had an underlying disease or obesity. In the same population, the vaccination rate was very low compared to that in the delta wave, indicating that non-vaccination significantly affected the progression to critical illness. Notably, there was a lack of prescription for Paxlovid for these patients although they satisfied the prescription criteria. Early diagnosis and active initial treatment was necessary, along with the proven methods of vaccination and personal hygiene. Further studies are needed to determine how each variant affects critically ill patients.
5.Reducing Microbial Contamination in Hematopoietic Stem Cell Products and Quality Improvement Strategy: Retrospective Analysis of 1996-2021 Data
You Keun KO ; Jong Kwon LEE ; Hye Kyung PARK ; Ae Kyung HAN ; Sun Kyoung MUN ; Hye Jeong PARK ; Hae Kyoung CHOUNG ; Se Mi KIM ; Kwang Mo CHOI ; Nam Yong LEE ; Duck CHO ; Dae Won KIM ; Eun-Suk KANG
Annals of Laboratory Medicine 2023;43(5):477-484
Background:
Sterility and safety assurance of hematopoietic stem cell (HSC) products is critical in transplantation. Microbial contamination can lead to product disposal and increases the risk of unsuccessful clinical outcomes. Therefore, it is important to implement and maintain good practice guidelines and regulations for the HSC collection and processing unit in each hospital. We aimed to share our experiences and suggest strategies to improve the quality assurance of HSC processing.
Methods:
We retrospectively analyzed microbial culture results of 11,743 HSC products processed over a 25-year period (January 1996 to May 2021). Because of reorganization of the HSC management system in 2008, the 25-year period was divided into periods 1 (January 1996 to December 2007) and 2 (January 2008 to May 2021). We reviewed all culture results of the HSC products and stored aliquot samples and collected culture results for peripheral blood and catheter samples.
Results:
Of the 11,743 products in total, 35 (0.3%) were contaminated by microorganisms, including 19 (0.5%) of 3,861 products during period 1 and 16 (0.2%) of 7,882 products during period 2. Penicillium was the most commonly identified microorganism (15.8%) during period 1 and coagulase-negative Staphylococcus was the most commonly identified (31.3%) during period 2. HSC product contamination occurred most often during HSC collection and processing.
Conclusions
The contamination rate decreased significantly during period 2, when the HSC management system was reorganized. Our results imply that handling HSC products by trained personnel and adopting established protocols, including quality assurance programs, aid in decreasing the contamination risk.
6.A Positive Association between the Atherogenic Index of Plasma and White Matter Hyperintensity
Hyun-Suk KWON ; Jun-Seong KO ; Jun-Hyuk LEE ; Kil-Young KWON ; Jee-Hye HAN
Korean Journal of Family Medicine 2022;43(3):193-198
Background:
White matter hyperintensity (WMH) is a risk factor for dementia and ischemic stroke. The atherogenic index of plasma (AIP) is a simple and cost-effective marker for the prediction of various vascular diseases. In this study, we evaluated the relationship between AIP and WMH in adults without cerebrovascular accidents.
Methods:
We analyzed the data of 281 adults, aged ≥26 years, who underwent brain magnetic resonance imaging (MRI) at the health promotion center of an education hospital between January 2014 and December 2018. Participants were divided into three categories according to tertiles of the AIP scores (T1: <0.20; T2: 0.20–0.48; and T3: >0.48). WMH was defined as a modified Fazekas scale score of 1–3 on brain MRI. A cubic spline curve was used to determine the linearity of the relationship between AIP and WMH. Multiple logistic regression analysis was used to evaluate the relationship between the AIP and WMH.
Results:
The prevalence of WMH was 45.7% in T1, 57.0% in T2, and 66.0% in T3 (T3 vs. T1, P for post-hoc analysis=0.005). The increased odds of WMH were associated with increased AIP. The odds ratio (OR) with a 95% confidence interval (CI) for WMH of T2 and T3 compared with T1 were 1.57 (0.88–2.80) and 2.30 (1.28–4.14), respectively. After adjusting for confounding variables, the OR with a 95% CI for WMH in the T2 and T3 groups vs. the referent T1 were 1.55 (0.76–3.13) and 2.27 (1.06–4.84), respectively.
Conclusion
AIP is independently and positively associated with WMH in a healthy population.
7.2020 Korean Consensus Guidelines for Diagnosis and Treatment of Chronic Hand Eczema
Hee Joo KIM ; Chul Hwan BANG ; Hye One KIM ; Dong Hoon LEE ; Joo Yeon KO ; Eun Joo PARK ; Sang Wook SON ; Young Suk RO ;
Annals of Dermatology 2021;33(4):351-361
Background:
Hand eczema refers to eczema located on the hands, regardless of its etiology or morphology. Despite its high prevalence and significant impact on patients’ quality of life, treatment is frequently challenging because of its heterogeneity, chronic and recurrent course, and lack of well-organized randomized controlled trials of the various treatment options.
Objective:
These consensus guidelines aim to provide evidence-based recommendations on the diagnosis and management of hand eczema to improve patient care by helping physicians make more efficient and transparent decisions.
Methods:
A modified Delphi method, comprising two rounds of email questionnaires with face-to-face meetings in between, was adopted for the consensus process that took place between February and September 2020. Forty experts in the field of skin allergy and contact dermatitis were invited to participate in the expert panel.
Results:
Consensus was reached for the domains of classification, diagnostic evaluation, and treatment; and a therapeutic ladder to manage chronic hand eczema was developed.
Conclusion
These are the first consensus guidelines for chronic hand eczema in the Asian population, which will help standardize care and assist clinical decision-making in the diagnosis and treatment of chronic hand eczema.
8.2020 Korean Consensus Guidelines for Diagnosis and Treatment of Chronic Hand Eczema
Hee Joo KIM ; Chul Hwan BANG ; Hye One KIM ; Dong Hoon LEE ; Joo Yeon KO ; Eun Joo PARK ; Sang Wook SON ; Young Suk RO ;
Annals of Dermatology 2021;33(4):351-361
Background:
Hand eczema refers to eczema located on the hands, regardless of its etiology or morphology. Despite its high prevalence and significant impact on patients’ quality of life, treatment is frequently challenging because of its heterogeneity, chronic and recurrent course, and lack of well-organized randomized controlled trials of the various treatment options.
Objective:
These consensus guidelines aim to provide evidence-based recommendations on the diagnosis and management of hand eczema to improve patient care by helping physicians make more efficient and transparent decisions.
Methods:
A modified Delphi method, comprising two rounds of email questionnaires with face-to-face meetings in between, was adopted for the consensus process that took place between February and September 2020. Forty experts in the field of skin allergy and contact dermatitis were invited to participate in the expert panel.
Results:
Consensus was reached for the domains of classification, diagnostic evaluation, and treatment; and a therapeutic ladder to manage chronic hand eczema was developed.
Conclusion
These are the first consensus guidelines for chronic hand eczema in the Asian population, which will help standardize care and assist clinical decision-making in the diagnosis and treatment of chronic hand eczema.
9.Impact of COVID-19-Related Stress and Depression in Public Sector Workers
Jinsol PARK ; Hye-mi CHO ; Min-soo KO ; Su-hyuk CHI ; Changsu HAN ; Hyun-suk YI ; Moon-Soo LEE
Korean Journal of Psychosomatic Medicine 2021;29(2):136-143
Objectives:
:The coronavirus disease 2019 (COVID-19) outbreak is a global medical crisis imposing particular burden on public sector employees. The aim of this study was to investigate the psychiatric distress among public sector workers amid the COVID-19 pandemic.
Methods:
:We conducted a cross-sectional study with 531 public sector workers in Gwangmyung city who completed Korean versions of the Perceived Stress Scale (PSS), Patient Health Questionnaire-9 (PHQ-9), and Impact of Event Scale-Revised-Korean (IES-R-K).
Results:
:The results revealed more than moderate levels of stress (85.2%), depressive symptoms (22.2%), and posttraumatic stress symptoms (38.8%). PSS total score was significantly correlated with PHQ-9, IES-R-K total scores as well as IES-R-K subscale scores. Total scores on the PSS, PHQ-9, and IES-R-K were all inversely correlated with age.
Conclusions
:COVID-19-related workers experience considerable stress and depressive symptoms, with self-rated stress correlating significantly with depression scores. Age may serve as a protective factor against oc-cupational stress and burnout. These findings highlight the need for adequate psychiatric screening and interven-tion for public sector workers.
10.Validation of a Strict Obesity Definition Proposed for Asians to Predict Adverse Pregnancy Outcomes in Korean Pregnant Women
Seo-Yeon KIM ; Soo-young OH ; Ji-Hee SUNG ; Suk-Joo CHOI ; Cheong-Rae ROH ; Seung Mi LEE ; Jong Kwan JUN ; Mi-Young LEE ; JoonHo LEE ; Soo Hyun KIM ; Dong Hyun CHA ; You Jung HAN ; Min Hyoung KIM ; Geum Joon CHO ; Han-Sung KWON ; Byoung Jae KIM ; Mi Hye PARK ; Hee Young CHO ; Hyun Sun KO ; Jae-Yoon SHIM ; Hyun Mee RYU
Journal of Korean Medical Science 2021;36(44):e281-
Background:
People are generally considered overweight and obese if their body mass index (BMI) is above 25 kg/m 2 and 30.0 kg/m 2 , respectively. The World Health Organization proposed stricter criteria for Asians (≥ 23 kg/m2 : overweight, ≥ 25 kg/m2 : obese). We aimed to verify whether this criteria could predict adverse pregnancy outcomes in Korean women.
Methods:
We included 7,547 Korean women from 12 institutions enrolled between June 2016 and October 2018. Women with no pre-pregnancy BMI data, not Korean, or lost to followup were excluded, leaving 6,331. The subjects were categorized into underweight, normal, overweight, class I obesity, and class II/III obesity based on a pre-pregnancy BMI of < 18.5, 18.5–22.9, 23.0–24.9, 25.0–29.9, and ≥ 30.0 kg/m2 , respectively.
Results:
Overall, 13.4%, 63.0%, 11.8%, 9.1%, and 2.6% of women were underweight, normal, and overweight and had class I obesity and class II/III obesity, respectively. In the multivariable analysis adjusted for maternal age, a higher BMI significantly increased the risk of preeclampsia, gestational diabetes, preterm delivery caused by maternal-fetal indications, cesarean section, large for gestational age, and neonatal intensive care unit admission.
Conclusion
Adverse pregnancy outcomes started to increase in those with a pre-pregnancy BMI ≥ 23.0 kg/m2 after adjusting for maternal age. The modified obesity criteria could help predict adverse pregnancy outcomes in Koreans.

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