1.Development and Application of New Risk-Adjustment Models to Improve the Current Model for Hospital Standardized Mortality Ratio in South Korea
Hyeki PARK ; Ji-Sook CHOI ; Min Sun SHIN ; Soomin KIM ; Hyekyoung KIM ; Nahyeong IM ; Soon Joo PARK ; Donggyo SHIN ; Youngmi SONG ; Yunjung CHO ; Hyunmi JOO ; Hyeryeon HONG ; Yong-Hwa HWANG ; Choon-Seon PARK
Yonsei Medical Journal 2025;66(3):179-186
		                        		
		                        			 Purpose:
		                        			This study assessed the validity of the hospital standardized mortality ratio (HSMR) risk-adjusted model by comparing models that include clinical information and the current model based on administrative information in South Korea. 
		                        		
		                        			Materials and Methods:
		                        			The data of 53976 inpatients were analyzed. The current HSMR risk-adjusted model (Model 1) adjusts for sex, age, health coverage, emergency hospitalization status, main diagnosis, surgery status, and Charlson Comorbidity Index (CCI) using administrative data. As candidate variables, among clinical information, the American Society of Anesthesiologists score, Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) 3, present on admission CCI, and cancer stage were collected. Surgery status, intensive care in the intensive care unit, and CCI were selected as proxy variables among administrative data. In-hospital death was defined as the dependent variable, and a logistic regression analysis was performed. The statistical performance of each model was compared using C-index values. 
		                        		
		                        			Results:
		                        			There was a strong correlation between variables in the administrative data and those in the medical records. The C-index of the existing model (Model 1) was 0.785; Model 2, which included all clinical data, had a higher C-index of 0.857. In Model 4, in which APACHE II and SAPS 3 were replaced with variables recorded in the administrative data from Model 2, the C-index further increased to 0.863. 
		                        		
		                        			Conclusion
		                        			The HSMR assessment model improved when clinical data were adjusted. Simultaneously, the validity of the evaluation method could be secured even if some of the clinical information was replaced with the information in the administrative data. 
		                        		
		                        		
		                        		
		                        	
2.Development and Application of New Risk-Adjustment Models to Improve the Current Model for Hospital Standardized Mortality Ratio in South Korea
Hyeki PARK ; Ji-Sook CHOI ; Min Sun SHIN ; Soomin KIM ; Hyekyoung KIM ; Nahyeong IM ; Soon Joo PARK ; Donggyo SHIN ; Youngmi SONG ; Yunjung CHO ; Hyunmi JOO ; Hyeryeon HONG ; Yong-Hwa HWANG ; Choon-Seon PARK
Yonsei Medical Journal 2025;66(3):179-186
		                        		
		                        			 Purpose:
		                        			This study assessed the validity of the hospital standardized mortality ratio (HSMR) risk-adjusted model by comparing models that include clinical information and the current model based on administrative information in South Korea. 
		                        		
		                        			Materials and Methods:
		                        			The data of 53976 inpatients were analyzed. The current HSMR risk-adjusted model (Model 1) adjusts for sex, age, health coverage, emergency hospitalization status, main diagnosis, surgery status, and Charlson Comorbidity Index (CCI) using administrative data. As candidate variables, among clinical information, the American Society of Anesthesiologists score, Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) 3, present on admission CCI, and cancer stage were collected. Surgery status, intensive care in the intensive care unit, and CCI were selected as proxy variables among administrative data. In-hospital death was defined as the dependent variable, and a logistic regression analysis was performed. The statistical performance of each model was compared using C-index values. 
		                        		
		                        			Results:
		                        			There was a strong correlation between variables in the administrative data and those in the medical records. The C-index of the existing model (Model 1) was 0.785; Model 2, which included all clinical data, had a higher C-index of 0.857. In Model 4, in which APACHE II and SAPS 3 were replaced with variables recorded in the administrative data from Model 2, the C-index further increased to 0.863. 
		                        		
		                        			Conclusion
		                        			The HSMR assessment model improved when clinical data were adjusted. Simultaneously, the validity of the evaluation method could be secured even if some of the clinical information was replaced with the information in the administrative data. 
		                        		
		                        		
		                        		
		                        	
3.Development and Application of New Risk-Adjustment Models to Improve the Current Model for Hospital Standardized Mortality Ratio in South Korea
Hyeki PARK ; Ji-Sook CHOI ; Min Sun SHIN ; Soomin KIM ; Hyekyoung KIM ; Nahyeong IM ; Soon Joo PARK ; Donggyo SHIN ; Youngmi SONG ; Yunjung CHO ; Hyunmi JOO ; Hyeryeon HONG ; Yong-Hwa HWANG ; Choon-Seon PARK
Yonsei Medical Journal 2025;66(3):179-186
		                        		
		                        			 Purpose:
		                        			This study assessed the validity of the hospital standardized mortality ratio (HSMR) risk-adjusted model by comparing models that include clinical information and the current model based on administrative information in South Korea. 
		                        		
		                        			Materials and Methods:
		                        			The data of 53976 inpatients were analyzed. The current HSMR risk-adjusted model (Model 1) adjusts for sex, age, health coverage, emergency hospitalization status, main diagnosis, surgery status, and Charlson Comorbidity Index (CCI) using administrative data. As candidate variables, among clinical information, the American Society of Anesthesiologists score, Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) 3, present on admission CCI, and cancer stage were collected. Surgery status, intensive care in the intensive care unit, and CCI were selected as proxy variables among administrative data. In-hospital death was defined as the dependent variable, and a logistic regression analysis was performed. The statistical performance of each model was compared using C-index values. 
		                        		
		                        			Results:
		                        			There was a strong correlation between variables in the administrative data and those in the medical records. The C-index of the existing model (Model 1) was 0.785; Model 2, which included all clinical data, had a higher C-index of 0.857. In Model 4, in which APACHE II and SAPS 3 were replaced with variables recorded in the administrative data from Model 2, the C-index further increased to 0.863. 
		                        		
		                        			Conclusion
		                        			The HSMR assessment model improved when clinical data were adjusted. Simultaneously, the validity of the evaluation method could be secured even if some of the clinical information was replaced with the information in the administrative data. 
		                        		
		                        		
		                        		
		                        	
4.Incidence of complicated appendicitis before and after the COVID-19 pandemic: a comparative analysis
Haksoo KIM ; Dongkil JEONG ; Young Soon CHO ; Geum Jong SONG ; Hyung Jun MOON ; Tae Yong SHIN ; Dong Wook LEE ; Hyun Joon KIM ; Hyun Jung LEE ; Sun In HONG
Journal of the Korean Society of Emergency Medicine 2025;36(1):12-19
		                        		
		                        			 Objective:
		                        			It has been 1 year since the start of the worldwide coronavirus disease-19 (COVID-19) pandemic. This study analyzed the indirect effects of COVID-19 on treating patients with non-infectious diseases by comparing the incidence of complicated appendicitis before and after the pandemic. 
		                        		
		                        			Methods:
		                        			The target group included patients aged at least 16 years diagnosed with acute appendicitis between February 23 and July 31, 2020. Patients diagnosed during the same period in 2019 were selected as the control group. The differences in the incidence of complicated appendicitis before and after COVID-19 were investigated, and the association with various variables was analyzed using the odds ratios and 95% confidence intervals (CIs). 
		                        		
		                        			Results:
		                        			The study included 120 subjects in 2019 (pre-COVID group) and 119 cases in 2020 (post-COVID group). The pre-COVID group included 25 cases (20.8%) of complicated appendicitis, while the post-COVID group included 48 cases (40.3%). The median time from symptom onset to visit (pre-hospital time) increased from 15 to 22 hours, and the median time from the visit to surgery (in-hospital time) increased from 7 to 11 hours. Multivariate regression analysis of the three variables revealed odds ratios (95% CIs) of pre-hospital time, erythrocyte sedimentation rate, and inclusion in the post-COVID group of 1.02 (1.01-1.02), 2.07 (1.11-3.86), and 2.15 (1.12-4.11), respectively. 
		                        		
		                        			Conclusion
		                        			The incidence of complicated appendicitis increased after the COVID-19 pandemic. Therefore, a healthcare system that can minimize the delay in treating non-infectious emergency patients is needed. 
		                        		
		                        		
		                        		
		                        	
5.Incidence of complicated appendicitis before and after the COVID-19 pandemic: a comparative analysis
Haksoo KIM ; Dongkil JEONG ; Young Soon CHO ; Geum Jong SONG ; Hyung Jun MOON ; Tae Yong SHIN ; Dong Wook LEE ; Hyun Joon KIM ; Hyun Jung LEE ; Sun In HONG
Journal of the Korean Society of Emergency Medicine 2025;36(1):12-19
		                        		
		                        			 Objective:
		                        			It has been 1 year since the start of the worldwide coronavirus disease-19 (COVID-19) pandemic. This study analyzed the indirect effects of COVID-19 on treating patients with non-infectious diseases by comparing the incidence of complicated appendicitis before and after the pandemic. 
		                        		
		                        			Methods:
		                        			The target group included patients aged at least 16 years diagnosed with acute appendicitis between February 23 and July 31, 2020. Patients diagnosed during the same period in 2019 were selected as the control group. The differences in the incidence of complicated appendicitis before and after COVID-19 were investigated, and the association with various variables was analyzed using the odds ratios and 95% confidence intervals (CIs). 
		                        		
		                        			Results:
		                        			The study included 120 subjects in 2019 (pre-COVID group) and 119 cases in 2020 (post-COVID group). The pre-COVID group included 25 cases (20.8%) of complicated appendicitis, while the post-COVID group included 48 cases (40.3%). The median time from symptom onset to visit (pre-hospital time) increased from 15 to 22 hours, and the median time from the visit to surgery (in-hospital time) increased from 7 to 11 hours. Multivariate regression analysis of the three variables revealed odds ratios (95% CIs) of pre-hospital time, erythrocyte sedimentation rate, and inclusion in the post-COVID group of 1.02 (1.01-1.02), 2.07 (1.11-3.86), and 2.15 (1.12-4.11), respectively. 
		                        		
		                        			Conclusion
		                        			The incidence of complicated appendicitis increased after the COVID-19 pandemic. Therefore, a healthcare system that can minimize the delay in treating non-infectious emergency patients is needed. 
		                        		
		                        		
		                        		
		                        	
6.Development and Application of New Risk-Adjustment Models to Improve the Current Model for Hospital Standardized Mortality Ratio in South Korea
Hyeki PARK ; Ji-Sook CHOI ; Min Sun SHIN ; Soomin KIM ; Hyekyoung KIM ; Nahyeong IM ; Soon Joo PARK ; Donggyo SHIN ; Youngmi SONG ; Yunjung CHO ; Hyunmi JOO ; Hyeryeon HONG ; Yong-Hwa HWANG ; Choon-Seon PARK
Yonsei Medical Journal 2025;66(3):179-186
		                        		
		                        			 Purpose:
		                        			This study assessed the validity of the hospital standardized mortality ratio (HSMR) risk-adjusted model by comparing models that include clinical information and the current model based on administrative information in South Korea. 
		                        		
		                        			Materials and Methods:
		                        			The data of 53976 inpatients were analyzed. The current HSMR risk-adjusted model (Model 1) adjusts for sex, age, health coverage, emergency hospitalization status, main diagnosis, surgery status, and Charlson Comorbidity Index (CCI) using administrative data. As candidate variables, among clinical information, the American Society of Anesthesiologists score, Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) 3, present on admission CCI, and cancer stage were collected. Surgery status, intensive care in the intensive care unit, and CCI were selected as proxy variables among administrative data. In-hospital death was defined as the dependent variable, and a logistic regression analysis was performed. The statistical performance of each model was compared using C-index values. 
		                        		
		                        			Results:
		                        			There was a strong correlation between variables in the administrative data and those in the medical records. The C-index of the existing model (Model 1) was 0.785; Model 2, which included all clinical data, had a higher C-index of 0.857. In Model 4, in which APACHE II and SAPS 3 were replaced with variables recorded in the administrative data from Model 2, the C-index further increased to 0.863. 
		                        		
		                        			Conclusion
		                        			The HSMR assessment model improved when clinical data were adjusted. Simultaneously, the validity of the evaluation method could be secured even if some of the clinical information was replaced with the information in the administrative data. 
		                        		
		                        		
		                        		
		                        	
7.Incidence of complicated appendicitis before and after the COVID-19 pandemic: a comparative analysis
Haksoo KIM ; Dongkil JEONG ; Young Soon CHO ; Geum Jong SONG ; Hyung Jun MOON ; Tae Yong SHIN ; Dong Wook LEE ; Hyun Joon KIM ; Hyun Jung LEE ; Sun In HONG
Journal of the Korean Society of Emergency Medicine 2025;36(1):12-19
		                        		
		                        			 Objective:
		                        			It has been 1 year since the start of the worldwide coronavirus disease-19 (COVID-19) pandemic. This study analyzed the indirect effects of COVID-19 on treating patients with non-infectious diseases by comparing the incidence of complicated appendicitis before and after the pandemic. 
		                        		
		                        			Methods:
		                        			The target group included patients aged at least 16 years diagnosed with acute appendicitis between February 23 and July 31, 2020. Patients diagnosed during the same period in 2019 were selected as the control group. The differences in the incidence of complicated appendicitis before and after COVID-19 were investigated, and the association with various variables was analyzed using the odds ratios and 95% confidence intervals (CIs). 
		                        		
		                        			Results:
		                        			The study included 120 subjects in 2019 (pre-COVID group) and 119 cases in 2020 (post-COVID group). The pre-COVID group included 25 cases (20.8%) of complicated appendicitis, while the post-COVID group included 48 cases (40.3%). The median time from symptom onset to visit (pre-hospital time) increased from 15 to 22 hours, and the median time from the visit to surgery (in-hospital time) increased from 7 to 11 hours. Multivariate regression analysis of the three variables revealed odds ratios (95% CIs) of pre-hospital time, erythrocyte sedimentation rate, and inclusion in the post-COVID group of 1.02 (1.01-1.02), 2.07 (1.11-3.86), and 2.15 (1.12-4.11), respectively. 
		                        		
		                        			Conclusion
		                        			The incidence of complicated appendicitis increased after the COVID-19 pandemic. Therefore, a healthcare system that can minimize the delay in treating non-infectious emergency patients is needed. 
		                        		
		                        		
		                        		
		                        	
8.Development and Application of New Risk-Adjustment Models to Improve the Current Model for Hospital Standardized Mortality Ratio in South Korea
Hyeki PARK ; Ji-Sook CHOI ; Min Sun SHIN ; Soomin KIM ; Hyekyoung KIM ; Nahyeong IM ; Soon Joo PARK ; Donggyo SHIN ; Youngmi SONG ; Yunjung CHO ; Hyunmi JOO ; Hyeryeon HONG ; Yong-Hwa HWANG ; Choon-Seon PARK
Yonsei Medical Journal 2025;66(3):179-186
		                        		
		                        			 Purpose:
		                        			This study assessed the validity of the hospital standardized mortality ratio (HSMR) risk-adjusted model by comparing models that include clinical information and the current model based on administrative information in South Korea. 
		                        		
		                        			Materials and Methods:
		                        			The data of 53976 inpatients were analyzed. The current HSMR risk-adjusted model (Model 1) adjusts for sex, age, health coverage, emergency hospitalization status, main diagnosis, surgery status, and Charlson Comorbidity Index (CCI) using administrative data. As candidate variables, among clinical information, the American Society of Anesthesiologists score, Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) 3, present on admission CCI, and cancer stage were collected. Surgery status, intensive care in the intensive care unit, and CCI were selected as proxy variables among administrative data. In-hospital death was defined as the dependent variable, and a logistic regression analysis was performed. The statistical performance of each model was compared using C-index values. 
		                        		
		                        			Results:
		                        			There was a strong correlation between variables in the administrative data and those in the medical records. The C-index of the existing model (Model 1) was 0.785; Model 2, which included all clinical data, had a higher C-index of 0.857. In Model 4, in which APACHE II and SAPS 3 were replaced with variables recorded in the administrative data from Model 2, the C-index further increased to 0.863. 
		                        		
		                        			Conclusion
		                        			The HSMR assessment model improved when clinical data were adjusted. Simultaneously, the validity of the evaluation method could be secured even if some of the clinical information was replaced with the information in the administrative data. 
		                        		
		                        		
		                        		
		                        	
9.Comparison of Statin With Ezetimibe Combination Therapy Versus Statin Monotherapy for Primary Prevention in Middle-Aged Adults
Jung-Joon CHA ; Soon Jun HONG ; Subin LIM ; Ju Hyeon KIM ; Hyung Joon JOO ; Jae Hyoung PARK ; Cheol Woong YU ; Do-Sun LIM ; Jang Young KIM ; Jin-Ok JEONG ; Jeong-Hun SHIN ; Chi Young SHIM ; Jong-Young LEE ; Young-Hyo LIM ; Sung Ha PARK ; Eun Joo CHO ; Hasung KIM ; Jungkuk LEE ; Ki-Chul SUNG ;
Korean Circulation Journal 2024;54(9):534-544
		                        		
		                        			 Background and Objectives:
		                        			Lipid lowering therapy is essential to reduce the risk of major cardiovascular events; however, limited evidence exists regarding the use of statin with ezetimibe as primary prevention strategy for middle-aged adults. We aimed to investigate the impact of single pill combination therapy on clinical outcomes in relatively healthy middleaged patients when compared with statin monotherapy. 
		                        		
		                        			Methods:
		                        			Using the Korean National Health Insurance Service database, a propensity score match analysis was performed for baseline characteristics of 92,156 patients categorized into combination therapy (n=46,078) and statin monotherapy (n=46,078) groups. Primary outcome was composite outcomes, including death, coronary artery disease, and ischemic stroke. And secondary outcome was all-cause death. The mean follow-up duration was 2.9±0.3 years. 
		                        		
		                        			Results:
		                        			The 3-year composite outcomes of all-cause death, coronary artery disease, and ischemic stroke demonstrated no significant difference between the 2 groups (10.3% vs.10.1%; hazard ratio [HR], 1.022; 95% confidence interval [CI], 0.980–1.064; p=0.309).Meanwhile, the 3-year all-cause death rate was lower in the combination therapy group than in the statin monotherapy group (0.2% vs. 0.4%; p<0.001), with a significant HR of 0.595 (95% CI, 0.460–0.769; p<0.001). Single pill combination therapy exhibited consistently lower mortality rates across various subgroups. 
		                        		
		                        			Conclusions
		                        			Compared to the statin monotherapy, the combination therapy for primary prevention showed no difference in composite outcomes but may reduce mortality risk in relatively healthy middle-aged patients. However, since the study was observational, further randomized clinical trials are needed to confirm these findings. 
		                        		
		                        		
		                        		
		                        	
10.Cohort profile: Multicenter Networks for Ideal Outcomes of Rare Pediatric Endocrine and Metabolic Diseases in Korea (OUTSPREAD study)
Yun Jeong LEE ; Chong Kun CHEON ; Junghwan SUH ; Jung-Eun MOON ; Moon Bae AHN ; Seong Hwan CHANG ; Jieun LEE ; Jin Ho CHOI ; Minsun KIM ; Han Hyuk LIM ; Jaehyun KIM ; Shin-Hye KIM ; Hae Sang LEE ; Yena LEE ; Eungu KANG ; Se Young KIM ; Yong Hee HONG ; Seung YANG ; Heon-Seok HAN ; Sochung CHUNG ; Won Kyoung CHO ; Eun Young KIM ; Jin Kyung KIM ; Kye Shik SHIM ; Eun-Gyong YOO ; Hae Soon KIM ; Aram YANG ; Sejin KIM ; Hyo-Kyoung NAM ; Sung Yoon CHO ; Young Ah LEE
Annals of Pediatric Endocrinology & Metabolism 2024;29(6):349-355
		                        		
		                        			
		                        			 Rare endocrine diseases are complex conditions that require lifelong specialized care due to their chronic nature and associated long-term complications. In Korea, a lack of nationwide data on clinical practice and outcomes has limited progress in patient care. Therefore, the Multicenter Networks for Ideal Outcomes of Pediatric Rare Endocrine and Metabolic Disease (OUTSPREAD) study was initiated. This study involves 30 centers across Korea. The study aims to improve the long-term prognosis of Korean patients with rare endocrine diseases by collecting comprehensive clinical data, biospecimens, and patient-reported outcomes to identify complications and unmet needs in patient care. Patients with childhood-onset pituitary, adrenal, or gonadal disorders, such as craniopharyngioma, congenital adrenal hyperplasia (CAH), and Turner syndrome were prioritized. The planned enrollment is 1,300 patients during the first study phase (2022–2024). Clinical, biochemical, and imaging data from diagnosis, treatment, and follow-up during 1980–2023 were retrospectively reviewed. For patients who agreed to participate in the prospective cohort, clinical data and biospecimens will be prospectively collected to discover ideal biomarkers that predict the effectiveness of disease control measures and prognosis. Patient-reported outcomes, including quality of life and depression scales, will be evaluated to assess psychosocial outcomes. Additionally, a substudy on CAH patients will develop a steroid hormone profiling method using liquid chromatography-tandem mass spectrometry to improve diagnosis and monitoring of treatment outcomes. This study will address unmet clinical needs by discovering ideal biomarkers, introducing evidence-based treatment guidelines, and ultimately improving long-term outcomes in the areas of rare endocrine and metabolic diseases. 
		                        		
		                        		
		                        		
		                        	
            
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