1.A Nationwide Survey on Infection Prevention and Control in Acute Care Hospitals of Korea
Sun Hee NA ; Yubin SEO ; Hye Jin SHI ; In Sun HWANG ; Kyong A SHIN ; Kwang Yul SON ; Sung Ran KIM ; Myoungjin SHIN ; Hee-jung SON ; Ji Youn CHOI ; Heekyung CHUN ; Sook-Kyung PARK ; Jeongsuk SONG ; Namyi KIM ; Jacob LEE ; Joong Sik EOM
Journal of Korean Medical Science 2025;40(4):e41-
		                        		
		                        			 Background:
		                        			Healthcare-associated infections impose a significant burden on antibiotic usage, healthcare expenditures, and morbidity. Therefore, it is crucial to revise policies to minimize such losses. This nationwide survey aimed to evaluate infection prevention and control (IPC) components in healthcare facilities and encourage improvements in acute care hospitals with inadequate infection prevention settings. This study aims to enhance the infection control capabilities of healthcare facilities. 
		                        		
		                        			Methods:
		                        			From December 27, 2021, to May 13, 2022, we conducted a survey of 1,767 acute care hospitals in the Republic of Korea. A survey was conducted to evaluate the infection control components in 1,767 acute care hospitals. Infection control officers provided direct responses to a systematically developed questionnaire. Subsequently, 10% of the respondents were randomly selected for the site investigation. 
		                        		
		                        			Results:
		                        			Overall, 1,197 (67.7%) hospitals responded to the online survey. On-site investigations were conducted at 125 hospitals. Hospitals with ≥ 150 beds are advised to have an IPC team under Article 3 of the Medical Service Act; however, only 87.0% (598/687) of hospitals with ≥ 100 beds had one. Conversely, 22.7% (116/510) of hospitals with < 100 beds had an IPC team. Regulations for hand hygiene, waste management, healthcare worker protection and safety, environmental cleaning, standard precautions, and prevention of the transmission of multidrug-resistant pathogens were present in 84.2%, 80.1%, 77.4%, 76.2%, 75.8%, and 63.5% of the hospitals, respectively. Hospitals with < 100 beds had low availability of all categories of standard operating procedures. 
		                        		
		                        			Conclusion
		                        			This study is the first national survey of acute care hospitals in the Republic of Korea. The data presented in the current study will improve the understanding of IPC status and will help establish a survey system. Our survey provides a basis for improving policies related to IPC in healthcare facilities. 
		                        		
		                        		
		                        		
		                        	
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.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
		                        		
		                        			
		                        			 Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity. 
		                        		
		                        		
		                        		
		                        	
4.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. 
		                        		
		                        		
		                        		
		                        	
5.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. 
		                        		
		                        		
		                        		
		                        	
6.A Nationwide Survey on Infection Prevention and Control in Acute Care Hospitals of Korea
Sun Hee NA ; Yubin SEO ; Hye Jin SHI ; In Sun HWANG ; Kyong A SHIN ; Kwang Yul SON ; Sung Ran KIM ; Myoungjin SHIN ; Hee-jung SON ; Ji Youn CHOI ; Heekyung CHUN ; Sook-Kyung PARK ; Jeongsuk SONG ; Namyi KIM ; Jacob LEE ; Joong Sik EOM
Journal of Korean Medical Science 2025;40(4):e41-
		                        		
		                        			 Background:
		                        			Healthcare-associated infections impose a significant burden on antibiotic usage, healthcare expenditures, and morbidity. Therefore, it is crucial to revise policies to minimize such losses. This nationwide survey aimed to evaluate infection prevention and control (IPC) components in healthcare facilities and encourage improvements in acute care hospitals with inadequate infection prevention settings. This study aims to enhance the infection control capabilities of healthcare facilities. 
		                        		
		                        			Methods:
		                        			From December 27, 2021, to May 13, 2022, we conducted a survey of 1,767 acute care hospitals in the Republic of Korea. A survey was conducted to evaluate the infection control components in 1,767 acute care hospitals. Infection control officers provided direct responses to a systematically developed questionnaire. Subsequently, 10% of the respondents were randomly selected for the site investigation. 
		                        		
		                        			Results:
		                        			Overall, 1,197 (67.7%) hospitals responded to the online survey. On-site investigations were conducted at 125 hospitals. Hospitals with ≥ 150 beds are advised to have an IPC team under Article 3 of the Medical Service Act; however, only 87.0% (598/687) of hospitals with ≥ 100 beds had one. Conversely, 22.7% (116/510) of hospitals with < 100 beds had an IPC team. Regulations for hand hygiene, waste management, healthcare worker protection and safety, environmental cleaning, standard precautions, and prevention of the transmission of multidrug-resistant pathogens were present in 84.2%, 80.1%, 77.4%, 76.2%, 75.8%, and 63.5% of the hospitals, respectively. Hospitals with < 100 beds had low availability of all categories of standard operating procedures. 
		                        		
		                        			Conclusion
		                        			This study is the first national survey of acute care hospitals in the Republic of Korea. The data presented in the current study will improve the understanding of IPC status and will help establish a survey system. Our survey provides a basis for improving policies related to IPC in healthcare facilities. 
		                        		
		                        		
		                        		
		                        	
7.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
		                        		
		                        			
		                        			 Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity. 
		                        		
		                        		
		                        		
		                        	
8.A Nationwide Survey on Infection Prevention and Control in Acute Care Hospitals of Korea
Sun Hee NA ; Yubin SEO ; Hye Jin SHI ; In Sun HWANG ; Kyong A SHIN ; Kwang Yul SON ; Sung Ran KIM ; Myoungjin SHIN ; Hee-jung SON ; Ji Youn CHOI ; Heekyung CHUN ; Sook-Kyung PARK ; Jeongsuk SONG ; Namyi KIM ; Jacob LEE ; Joong Sik EOM
Journal of Korean Medical Science 2025;40(4):e41-
		                        		
		                        			 Background:
		                        			Healthcare-associated infections impose a significant burden on antibiotic usage, healthcare expenditures, and morbidity. Therefore, it is crucial to revise policies to minimize such losses. This nationwide survey aimed to evaluate infection prevention and control (IPC) components in healthcare facilities and encourage improvements in acute care hospitals with inadequate infection prevention settings. This study aims to enhance the infection control capabilities of healthcare facilities. 
		                        		
		                        			Methods:
		                        			From December 27, 2021, to May 13, 2022, we conducted a survey of 1,767 acute care hospitals in the Republic of Korea. A survey was conducted to evaluate the infection control components in 1,767 acute care hospitals. Infection control officers provided direct responses to a systematically developed questionnaire. Subsequently, 10% of the respondents were randomly selected for the site investigation. 
		                        		
		                        			Results:
		                        			Overall, 1,197 (67.7%) hospitals responded to the online survey. On-site investigations were conducted at 125 hospitals. Hospitals with ≥ 150 beds are advised to have an IPC team under Article 3 of the Medical Service Act; however, only 87.0% (598/687) of hospitals with ≥ 100 beds had one. Conversely, 22.7% (116/510) of hospitals with < 100 beds had an IPC team. Regulations for hand hygiene, waste management, healthcare worker protection and safety, environmental cleaning, standard precautions, and prevention of the transmission of multidrug-resistant pathogens were present in 84.2%, 80.1%, 77.4%, 76.2%, 75.8%, and 63.5% of the hospitals, respectively. Hospitals with < 100 beds had low availability of all categories of standard operating procedures. 
		                        		
		                        			Conclusion
		                        			This study is the first national survey of acute care hospitals in the Republic of Korea. The data presented in the current study will improve the understanding of IPC status and will help establish a survey system. Our survey provides a basis for improving policies related to IPC in healthcare facilities. 
		                        		
		                        		
		                        		
		                        	
9.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. 
		                        		
		                        		
		                        		
		                        	
10.Role of HIF-1α in the Responses of Tumors to Radiotherapy and Chemotherapy
Chang W SONG ; Hyunkyung KIM ; Mi-Sook KIM ; Heon J PARK ; Sun-Ha PAEK ; Stephanie TEREZAKIS ; L Chinsoo CHO
Cancer Research and Treatment 2025;57(1):1-10
		                        		
		                        			
		                        			 Tumor microenvironment is intrinsically hypoxic with abundant hypoxia-inducible factors-1α (HIF-1α), a primary regulator of the cellular response to hypoxia and various stresses imposed on the tumor cells. HIF-1α increases radioresistance and chemoresistance by reducing DNA damage, increasing repair of DNA damage, enhancing glycolysis that increases antioxidant capacity of tumors cells, and promoting angiogenesis. In addition, HIF-1α markedly enhances drug efflux, leading to multidrug resistance. Radiotherapy and certain chemotherapy drugs evoke profound anti-tumor immunity by inducing immunologic cell death that release tumor-associated antigens together with numerous pro-immunological factors, leading to priming of cytotoxic CD8+ T cells and enhancing the cytotoxicity of macrophages and natural killer cells. Radiotherapy and chemotherapy of tumors significantly increase HIF-1α activity in tumor cells. Unfortunately, HIF-1α effectively promotes various immune suppressive pathways including secretion of immune suppressive cytokines, activation of myeloid-derived suppressor cells, activation of regulatory T cells, inhibition of T cells priming and activity, and upregulation of immune checkpoints. Consequently, the anti-tumor immunity elevated by radiotherapy and chemotherapy is counterbalanced or masked by the potent immune suppression promoted by HIF-1α. Effective inhibition of HIF-1α may significantly increase the efficacy of radiotherapy and chemotherapy by increasing radiosensitivity and chemosensitivity of tumor cells and also by upregulating anti-tumor immunity. 
		                        		
		                        		
		                        		
		                        	
            
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