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.Prevalence of Carbon Monoxide Poisoning and Hyperbaric Oxygen Therapy in Korea: Analysis of National Claims Data in 2010–2019
Eunah HAN ; Gina YU ; Hye Sun LEE ; Goeun PARK ; Sung Phil CHUNG
Journal of Korean Medical Science 2023;38(15):e125-
This study aimed to investigate the prevalence of carbon monoxide (CO) poisoning and the provision of hyperbaric oxygen therapy (HBOT) in South Korea. We used data from the Korea Health Insurance Review and Assessment service. In total, 44,361 patients with CO poisoning were identified across 10 years (2010–2019). The prevalence of CO poisoning was found to be 8.64/10,000 people, with a gradual annual increment. The highest prevalence was 11.01/10,000 individuals, among those aged 30–39 years. In 2010, HBOT was claimed from 15 hospitals, and increased to 30 hospitals in 2019. A total of 4,473 patients received HBOT in 10 years and 2,684 (60%) were treated for more than 2 hours. This study suggested that the prevalence of both CO poisoning and HBOT in Korea gradually increased over the past 10 years, and disparities in prevalence were observed by region.
5.Status and trends of medical expenditures for poisoning patients
Eung Nam KIM ; Soyoung JEON ; Hye Sun LEE ; Sung Phil CHUNG
Journal of The Korean Society of Clinical Toxicology 2023;21(1):24-31
Purpose:
The purpose of this study was to estimate the medical expenditures for poisoning patients in Korea using data from National Health Insurance and the Korea Health Panel Survey.
Methods:
The operational definition of poisoning was the presence of Korean Standard Classification of Diseases codes from T36 to T65. The number of poisoning patients, the amount of legal copayments, and benefit and non-benefit costs were extracted from both databases. The frequency of emergency, inpatient, and outpatient treatment utilization by poisoning patients was determined, and medical expenses were calculated. Linear regression analyses were performed to investigate factors affecting the medical expenses of poisoning patients.
Results:
The number of poisoning patients increased from 97,965 in 2011 to 147,984 persons in 2020. Medical expenses also increased by 74% from Korean won (KRW) 30.1 billion to KRW 52.3 billion, and benefit costs also increased by 79%. The average outpatient cost per person was KRW 67,660, and the inpatient cost was KRW 1,485,103. The average non-benefit medical expenses were KRW 80,298, accounting for about 16.2% of the total expenses. Multivariable analysis showed that the total expenditure was associated with economic status and disabilities.
Conclusion
The average medical expenditure per poisoning patient was KRW 534,302 in 2020, and poisoning-related costs gradually increased during the study period. Further research on the economic burden of poisoning should include indirect costs and reflect disease-adjusted life years.
6.Thrombotic Microangiopathy Score as a New Predictor of Neurologic Outcomes in Patients after Out-of-Hospital Cardiac Arrest
Je Sung YOU ; Hye Sun LEE ; Soyoung JEON ; Jong Wook LEE ; Hyun Soo CHUNG ; Sung Phil CHUNG ; Taeyoung KONG
Yonsei Medical Journal 2022;63(5):461-469
Purpose:
Given the morphological characteristics of schistocytes, thrombotic microangiopathy (TMA) score can be beneficial as it can be automatically and accurately measured. This study aimed to investigate whether serial TMA scores until 48 h post admission are associated with clinical outcomes in patients undergoing targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA).
Materials and Methods:
We retrospectively evaluated a cohort of 185 patients using a prospective registry. We analyzed TMA scores at admission and after 12, 24, and 48 hours. The primary outcome measures were poor neurological outcome at discharge and 30-day mortality.
Results:
Increased TMA scores at all measured time points were independent predictors of poor neurological outcomes and 30-day mortality, with TMA score at time-12 showing the strongest correlation [odds ratio (OR), 3.008; 95% confidence interval (CI), 1.707–5.300; p<0.001 and hazard ratio (HR), 1.517; 95% CI, 1.196–1.925; p<0.001]. Specifically, a TMA score ≥2 at time-12 was closely associated with an increased predictability of poor neurological outcomes (OR, 6.302; 95% CI, 2.841–13.976; p<0.001) and 30-day mortality (HR, 2.656; 95% CI, 1.675–4.211; p<0.001).
Conclusion
Increased TMA scores predicted neurological outcomes and 30-day mortality in patients undergoing TTM after OHCA. In addition to the benefit of being serially measured using an automated hematology analyzer, TMA score may be a helpful tool for rapid risk stratification and identification of the need for intensive care in patients with return of spontaneous circulation after OHCA.
8.Effect of fast track on prognosis in patients with common bile duct obstruction with cholangitis in emergency department
Sang Yong LEE ; Sung Ill JANG ; Sung Phil CHUNG ; Hye Sun LEE ; Soyoung JEON ; Je Sung YOU ; Tae Young KONG ; Jin Ho BEOM ; Dong Ryul KO
Journal of the Korean Society of Emergency Medicine 2022;33(3):279-287
Objective:
Biliary decompression through bile drainage is a key treatment for common bile duct obstruction with cholangitis. However, the effectiveness of early interventions has not been studied sufficiently in Korea. This study investigated the effectiveness of fast-track biliary decompression.
Methods:
A group of patients diagnosed with common bile duct obstruction with cholangitis between January 1, 2014, and December 31, 2019, was reviewed retrospectively. We divided them into two groups: before and after the implementation of fast-track biliary decompression. The following items were analyzed in the two groups: time to intervention, number of hospital days, length of stay in the emergency department, and intensive care unit (ICU) admission.
Results:
Between January 1, 2014, and December 31, 2019, 418 patients were admitted for common bile duct obstruction, and a total of 369 patients were included in this study. Of these, 168 patients visited the hospital prior to implementation of the treatment, and 201 patients visited after implementation. The time to intervention was 6.1 (4.2-11.0) hours in the fast-track group, which was about 9 hours shorter than the other group (P<0.001). There was no statistical difference in the number of hospital days, emergency department length of stay, and ICU admissions (P=0.535, P=0.034, P=0.322).
Conclusion
The time to intervention was shortened significantly in the fast-track group. However, we did not observe a significant improvement in patient prognosis. It may be possible that the procedure time may need to be shortened for a better prognosis. This should be investigated in future studies.
9.Maternal and Neonatal Outcomes in Pregnant Women With Coronavirus Disease 2019 in Korea
Youseung CHUNG ; Eun Jin KIM ; Hee-Sung KIM ; Kyung-Hwa PARK ; Ji Hyeon BAEK ; Jungok KIM ; Ji Yeon LEE ; Chang-Seop LEE ; Seungjin LIM ; Shin-Woo KIM ; Eu Suk KIM ; Hye Jin SHI ; Shin Hee HONG ; Jae-Bum JUN ; Kyung-Wook HONG ; Jae-Phil CHOI ; Jinyeong KIM ; Kyung Sook YANG ; Young Kyung YOON
Journal of Korean Medical Science 2022;37(41):e297-
Background:
This study aimed to describe the maternal, obstetrical, and neonatal outcomes in pregnant women with coronavirus disease 2019 (COVID-19) and identify the predictors associated with the severity of COVID-19.
Methods:
This multicenter observational study included consecutive pregnant women admitted because of COVID-19 confirmed using reverse transcriptase-polymerase chain reaction (RT-PCR) test at 15 hospitals in the Republic of Korea between January 2020 and December 2021.
Results:
A total of 257 women with COVID-19 and 62 newborns were included in this study. Most of the patients developed this disease during the third trimester. Nine patients (7.4%) developed pregnancy-related complications. All pregnant women received inpatient treatment, of whom 9 (3.5%) required intensive care, but none of them died. The gestational age at COVID-19 diagnosis (odds ratio [OR], 1.096, 95% confidence interval [CI], 1.04–1.15) and parity (OR, 1.703, 95% CI, 1.13–2.57) were identified as significant risk factors of severe diseases. Among women who delivered, 78.5% underwent cesarean section. Preterm birth (38.5%), premature rupture of membranes (7.7%), and miscarriage (4.6%) occurred, but there was no stillbirth or neonatal death. The RT-PCR test of newborns’ amniotic fluid and umbilical cord blood samples was negative for severe acute respiratory syndrome coronavirus 2.
Conclusion
At the time of COVID-19 diagnosis, gestational age and parity of pregnant women were the risk factors of disease severity. Vertical transmission of COVID-19 was not observed, and maternal severity did not significantly affect the neonatal prognosis.
10.Potential Link Between Cognition and Motor Reserve in Patients With Parkinson’s Disease
Seok Jong CHUNG ; Yae Ji KIM ; Yun Joong KIM ; Hye Sun LEE ; Mijin YUN ; Phil Hyu LEE ; Yong JEONG ; Young H. SOHN
Journal of Movement Disorders 2022;15(3):249-257
Objective:
To investigate whether there is a link between cognitive function and motor reserve (i.e., individual capacity to cope with nigrostriatal dopamine depletion) in patients with newly diagnosed Parkinson’s disease (PD).
Methods:
A total of 163 patients with drug-naïve PD who underwent 18F-FP-CIT PET, brain MRI, and a detailed neuropsychological test were enrolled. We estimated individual motor reserve based on initial motor deficits and striatal dopamine depletion using a residual model. We performed correlation analyses between motor reserve estimates and cognitive composite scores. Diffusion connectometry analysis was performed to map the white matter fiber tracts, of which fractional anisotropy (FA) values were well correlated with motor reserve estimates. Additionally, Cox regression analysis was used to assess the effect of initial motor reserve on the risk of dementia conversion.
Results:
The motor reserve estimate was positively correlated with the composite score of the verbal memory function domain (γ = 0.246) and with the years of education (γ = 0.251). Connectometry analysis showed that FA values in the left fornix were positively correlated with the motor reserve estimate, while no fiber tracts were negatively correlated with the motor reserve estimate. Cox regression analysis demonstrated that higher motor reserve estimates tended to be associated with a lower risk of dementia conversion (hazard ratio, 0.781; 95% confidence interval, 0.576–1.058).
Conclusion
The present study demonstrated that the motor reserve estimate was well correlated with verbal memory function and with white matter integrity in the left fornix, suggesting a possible link between cognition and motor reserve in patients with PD.

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