1.The Impact of Hospital Volume and Region on Mortality, Medical Costs, and Length of Hospital Stay in Elderly Patients Following Hip Fracture:A Nationwide Claims Database Analysis
Seung Hoon KIM ; Suk-Yong JANG ; Yonghan CHA ; Hajun JANG ; Bo-Yeon KIM ; Hyo-Jung LEE ; Gui-Ok KIM
Clinics in Orthopedic Surgery 2025;17(1):80-90
Background:
The purpose of our study was to analyze the effects of hospital volume and region on in-hospital and long-term mortality, direct medical costs (DMCs), and length of hospital stay (LOS) in elderly patients following hip fracture, utilizing nationwide claims data.
Methods:
This retrospective nationwide study sourced its subjects from the Korean National Health Insurance Review and Assessment Service database spanning from January 2011 to December 2018. A generalized estimating equation model with a Poisson distribution and logarithmic link function was used to estimate adjusted odds ratios (aORs) and 95% CIs to assess the association of hospital volume with in-hospital and 1-year mortality, DMCs, and LOS .
Results:
A total of 172,144 patients were included. Comparing the risk of in-hospital death between high-volume and low-volume hospitals, the risk of in-hospital death was 1.2 times higher at low-volume hospitals (aOR, 1.20; 95% CI, 1.07–1.33; p = 0.002).Additionally, the risk of death at 1 year was 1.05 times higher at low-volume hospitals (aOR, 1.05; 95% CI, 1.01–1.09; p = 0.008) compared to high-volume hospitals. DMCs were 0.84 times lower at low-volume hospitals for in-hospital period (aOR, 0.84; 95% CI, 0.84–0.85; p < 0.001) and 0.87 times lower for 1 year (aOR, 0.87; 95% CI, 0.86–0.88; p < 0.001) compared to high-volume hospitals. In-hospital LOS was 1.21 times longer at low-volume hospitals (aOR, 1.21; 95% CI, 1.20–1.22; p < 0.001) than at high-volume hospitals. In addition, the risk of in-hospital death was 1.22 times higher (aOR, 1.22; 95% CI, 1.12–1.33; p < 0.001) and the risk of 1-year death was 1.07 times higher (aOR, 1.07; 95% CI, 1.04–1.10; p < 0.001) at rural hospitals compared to urban hospitals.
Conclusions
Clinicians should focus on improving clinical outcomes for hip fracture patients in low-volume and rural hospital settings, with a specific emphasis on reducing mortality rates.
2.Tuberculous and Malignant Pleural Effusions With Adenosine Deaminase Levels of 40–70 IU/L: Trends in New Cases Over Time and Differentiation Between Groups
Jaehee LEE ; Jongmin PARK ; Jae Kwang LIM ; Ji Eun PARK ; Yong Hoon LEE ; Sun Ha CHOI ; Hyewon SEO ; Seung Soo YOO ; Shin Yup LEE ; Seung-Ick CHA ; Jae Yong PARK ; Chang Ho KIM
Journal of Korean Medical Science 2025;40(13):e35-
Background:
The diagnosis of tuberculous pleural effusion (TPE) often relies on pleural fluid adenosine deaminase (ADA) levels. The diagnostic utility of ADA, however, is influenced by the prevalence of tuberculosis (TB) in local populations. Malignant pleural effusion (MPE) cases can exhibit moderately elevated ADA levels comparable to those seen in TPE. As population aging potentially impacts ADA levels, global TB incidence is decreasing whereas the burden of malignancy is on the rise. Consequently, epidemiological shifts and temporal changes in ADA distribution complicate the differential diagnosis between TPE and MPE when ADA levels are within the 40–70 IU/L range. Nonetheless, data specific to this subset are scarce.
Methods:
This retrospective study included consecutive patients aged > 18 years with confirmed TPE and MPE, spanning from 2012 to 2023. ADA levels in pleural fluid were categorized into three groups: < 40 IU/L, 40–70 IU/L, and > 70 IU/L. The study examined annual trends in the frequency of new cases and ADA level distributions over time and identified discriminating factors between TPE and MPE in cases with ADA levels of 40–70 IU/L.
Results:
In total, 297 TPE and 369 MPE cases were included in this study. Over the study period, the frequency of TPE progressively declined, while that of MPE increased. In the most recent four-year period, new TPE and MPE cases with ADA levels of 40–70 IU/L occurred at comparable numbers. Multivariable analysis identified pleural fluid carcinoembryonic antigen (CEA) levels and the number of focal pleural nodules as independent predictors for MPE. Specifically, the presence of either CEA levels > 15.7 ng/mL or more than eight pleural nodules yielded the highest diagnostic accuracy with a sensitivity of 88%, specificity of 100%, and an area under the curve of 0.95.
Conclusion
The differential diagnosis between TPE and MPE with pleural ADA levels of 40–70 IU/L has become increasingly critical due to evolving epidemiological patterns and ADA distribution changes over time. Pleural fluid CEA levels and the characteristics of pleural nodules may offer valuable guidance in distinguishing between TPE and MPE within this diagnostic gray zone.
3.Tuberculous and Malignant Pleural Effusions With Adenosine Deaminase Levels of 40–70 IU/L: Trends in New Cases Over Time and Differentiation Between Groups
Jaehee LEE ; Jongmin PARK ; Jae Kwang LIM ; Ji Eun PARK ; Yong Hoon LEE ; Sun Ha CHOI ; Hyewon SEO ; Seung Soo YOO ; Shin Yup LEE ; Seung-Ick CHA ; Jae Yong PARK ; Chang Ho KIM
Journal of Korean Medical Science 2025;40(13):e35-
Background:
The diagnosis of tuberculous pleural effusion (TPE) often relies on pleural fluid adenosine deaminase (ADA) levels. The diagnostic utility of ADA, however, is influenced by the prevalence of tuberculosis (TB) in local populations. Malignant pleural effusion (MPE) cases can exhibit moderately elevated ADA levels comparable to those seen in TPE. As population aging potentially impacts ADA levels, global TB incidence is decreasing whereas the burden of malignancy is on the rise. Consequently, epidemiological shifts and temporal changes in ADA distribution complicate the differential diagnosis between TPE and MPE when ADA levels are within the 40–70 IU/L range. Nonetheless, data specific to this subset are scarce.
Methods:
This retrospective study included consecutive patients aged > 18 years with confirmed TPE and MPE, spanning from 2012 to 2023. ADA levels in pleural fluid were categorized into three groups: < 40 IU/L, 40–70 IU/L, and > 70 IU/L. The study examined annual trends in the frequency of new cases and ADA level distributions over time and identified discriminating factors between TPE and MPE in cases with ADA levels of 40–70 IU/L.
Results:
In total, 297 TPE and 369 MPE cases were included in this study. Over the study period, the frequency of TPE progressively declined, while that of MPE increased. In the most recent four-year period, new TPE and MPE cases with ADA levels of 40–70 IU/L occurred at comparable numbers. Multivariable analysis identified pleural fluid carcinoembryonic antigen (CEA) levels and the number of focal pleural nodules as independent predictors for MPE. Specifically, the presence of either CEA levels > 15.7 ng/mL or more than eight pleural nodules yielded the highest diagnostic accuracy with a sensitivity of 88%, specificity of 100%, and an area under the curve of 0.95.
Conclusion
The differential diagnosis between TPE and MPE with pleural ADA levels of 40–70 IU/L has become increasingly critical due to evolving epidemiological patterns and ADA distribution changes over time. Pleural fluid CEA levels and the characteristics of pleural nodules may offer valuable guidance in distinguishing between TPE and MPE within this diagnostic gray zone.
4.The Impact of Hospital Volume and Region on Mortality, Medical Costs, and Length of Hospital Stay in Elderly Patients Following Hip Fracture:A Nationwide Claims Database Analysis
Seung Hoon KIM ; Suk-Yong JANG ; Yonghan CHA ; Hajun JANG ; Bo-Yeon KIM ; Hyo-Jung LEE ; Gui-Ok KIM
Clinics in Orthopedic Surgery 2025;17(1):80-90
Background:
The purpose of our study was to analyze the effects of hospital volume and region on in-hospital and long-term mortality, direct medical costs (DMCs), and length of hospital stay (LOS) in elderly patients following hip fracture, utilizing nationwide claims data.
Methods:
This retrospective nationwide study sourced its subjects from the Korean National Health Insurance Review and Assessment Service database spanning from January 2011 to December 2018. A generalized estimating equation model with a Poisson distribution and logarithmic link function was used to estimate adjusted odds ratios (aORs) and 95% CIs to assess the association of hospital volume with in-hospital and 1-year mortality, DMCs, and LOS .
Results:
A total of 172,144 patients were included. Comparing the risk of in-hospital death between high-volume and low-volume hospitals, the risk of in-hospital death was 1.2 times higher at low-volume hospitals (aOR, 1.20; 95% CI, 1.07–1.33; p = 0.002).Additionally, the risk of death at 1 year was 1.05 times higher at low-volume hospitals (aOR, 1.05; 95% CI, 1.01–1.09; p = 0.008) compared to high-volume hospitals. DMCs were 0.84 times lower at low-volume hospitals for in-hospital period (aOR, 0.84; 95% CI, 0.84–0.85; p < 0.001) and 0.87 times lower for 1 year (aOR, 0.87; 95% CI, 0.86–0.88; p < 0.001) compared to high-volume hospitals. In-hospital LOS was 1.21 times longer at low-volume hospitals (aOR, 1.21; 95% CI, 1.20–1.22; p < 0.001) than at high-volume hospitals. In addition, the risk of in-hospital death was 1.22 times higher (aOR, 1.22; 95% CI, 1.12–1.33; p < 0.001) and the risk of 1-year death was 1.07 times higher (aOR, 1.07; 95% CI, 1.04–1.10; p < 0.001) at rural hospitals compared to urban hospitals.
Conclusions
Clinicians should focus on improving clinical outcomes for hip fracture patients in low-volume and rural hospital settings, with a specific emphasis on reducing mortality rates.
5.The Impact of Hospital Volume and Region on Mortality, Medical Costs, and Length of Hospital Stay in Elderly Patients Following Hip Fracture:A Nationwide Claims Database Analysis
Seung Hoon KIM ; Suk-Yong JANG ; Yonghan CHA ; Hajun JANG ; Bo-Yeon KIM ; Hyo-Jung LEE ; Gui-Ok KIM
Clinics in Orthopedic Surgery 2025;17(1):80-90
Background:
The purpose of our study was to analyze the effects of hospital volume and region on in-hospital and long-term mortality, direct medical costs (DMCs), and length of hospital stay (LOS) in elderly patients following hip fracture, utilizing nationwide claims data.
Methods:
This retrospective nationwide study sourced its subjects from the Korean National Health Insurance Review and Assessment Service database spanning from January 2011 to December 2018. A generalized estimating equation model with a Poisson distribution and logarithmic link function was used to estimate adjusted odds ratios (aORs) and 95% CIs to assess the association of hospital volume with in-hospital and 1-year mortality, DMCs, and LOS .
Results:
A total of 172,144 patients were included. Comparing the risk of in-hospital death between high-volume and low-volume hospitals, the risk of in-hospital death was 1.2 times higher at low-volume hospitals (aOR, 1.20; 95% CI, 1.07–1.33; p = 0.002).Additionally, the risk of death at 1 year was 1.05 times higher at low-volume hospitals (aOR, 1.05; 95% CI, 1.01–1.09; p = 0.008) compared to high-volume hospitals. DMCs were 0.84 times lower at low-volume hospitals for in-hospital period (aOR, 0.84; 95% CI, 0.84–0.85; p < 0.001) and 0.87 times lower for 1 year (aOR, 0.87; 95% CI, 0.86–0.88; p < 0.001) compared to high-volume hospitals. In-hospital LOS was 1.21 times longer at low-volume hospitals (aOR, 1.21; 95% CI, 1.20–1.22; p < 0.001) than at high-volume hospitals. In addition, the risk of in-hospital death was 1.22 times higher (aOR, 1.22; 95% CI, 1.12–1.33; p < 0.001) and the risk of 1-year death was 1.07 times higher (aOR, 1.07; 95% CI, 1.04–1.10; p < 0.001) at rural hospitals compared to urban hospitals.
Conclusions
Clinicians should focus on improving clinical outcomes for hip fracture patients in low-volume and rural hospital settings, with a specific emphasis on reducing mortality rates.
6.Tuberculous and Malignant Pleural Effusions With Adenosine Deaminase Levels of 40–70 IU/L: Trends in New Cases Over Time and Differentiation Between Groups
Jaehee LEE ; Jongmin PARK ; Jae Kwang LIM ; Ji Eun PARK ; Yong Hoon LEE ; Sun Ha CHOI ; Hyewon SEO ; Seung Soo YOO ; Shin Yup LEE ; Seung-Ick CHA ; Jae Yong PARK ; Chang Ho KIM
Journal of Korean Medical Science 2025;40(13):e35-
Background:
The diagnosis of tuberculous pleural effusion (TPE) often relies on pleural fluid adenosine deaminase (ADA) levels. The diagnostic utility of ADA, however, is influenced by the prevalence of tuberculosis (TB) in local populations. Malignant pleural effusion (MPE) cases can exhibit moderately elevated ADA levels comparable to those seen in TPE. As population aging potentially impacts ADA levels, global TB incidence is decreasing whereas the burden of malignancy is on the rise. Consequently, epidemiological shifts and temporal changes in ADA distribution complicate the differential diagnosis between TPE and MPE when ADA levels are within the 40–70 IU/L range. Nonetheless, data specific to this subset are scarce.
Methods:
This retrospective study included consecutive patients aged > 18 years with confirmed TPE and MPE, spanning from 2012 to 2023. ADA levels in pleural fluid were categorized into three groups: < 40 IU/L, 40–70 IU/L, and > 70 IU/L. The study examined annual trends in the frequency of new cases and ADA level distributions over time and identified discriminating factors between TPE and MPE in cases with ADA levels of 40–70 IU/L.
Results:
In total, 297 TPE and 369 MPE cases were included in this study. Over the study period, the frequency of TPE progressively declined, while that of MPE increased. In the most recent four-year period, new TPE and MPE cases with ADA levels of 40–70 IU/L occurred at comparable numbers. Multivariable analysis identified pleural fluid carcinoembryonic antigen (CEA) levels and the number of focal pleural nodules as independent predictors for MPE. Specifically, the presence of either CEA levels > 15.7 ng/mL or more than eight pleural nodules yielded the highest diagnostic accuracy with a sensitivity of 88%, specificity of 100%, and an area under the curve of 0.95.
Conclusion
The differential diagnosis between TPE and MPE with pleural ADA levels of 40–70 IU/L has become increasingly critical due to evolving epidemiological patterns and ADA distribution changes over time. Pleural fluid CEA levels and the characteristics of pleural nodules may offer valuable guidance in distinguishing between TPE and MPE within this diagnostic gray zone.
7.The Impact of Hospital Volume and Region on Mortality, Medical Costs, and Length of Hospital Stay in Elderly Patients Following Hip Fracture:A Nationwide Claims Database Analysis
Seung Hoon KIM ; Suk-Yong JANG ; Yonghan CHA ; Hajun JANG ; Bo-Yeon KIM ; Hyo-Jung LEE ; Gui-Ok KIM
Clinics in Orthopedic Surgery 2025;17(1):80-90
Background:
The purpose of our study was to analyze the effects of hospital volume and region on in-hospital and long-term mortality, direct medical costs (DMCs), and length of hospital stay (LOS) in elderly patients following hip fracture, utilizing nationwide claims data.
Methods:
This retrospective nationwide study sourced its subjects from the Korean National Health Insurance Review and Assessment Service database spanning from January 2011 to December 2018. A generalized estimating equation model with a Poisson distribution and logarithmic link function was used to estimate adjusted odds ratios (aORs) and 95% CIs to assess the association of hospital volume with in-hospital and 1-year mortality, DMCs, and LOS .
Results:
A total of 172,144 patients were included. Comparing the risk of in-hospital death between high-volume and low-volume hospitals, the risk of in-hospital death was 1.2 times higher at low-volume hospitals (aOR, 1.20; 95% CI, 1.07–1.33; p = 0.002).Additionally, the risk of death at 1 year was 1.05 times higher at low-volume hospitals (aOR, 1.05; 95% CI, 1.01–1.09; p = 0.008) compared to high-volume hospitals. DMCs were 0.84 times lower at low-volume hospitals for in-hospital period (aOR, 0.84; 95% CI, 0.84–0.85; p < 0.001) and 0.87 times lower for 1 year (aOR, 0.87; 95% CI, 0.86–0.88; p < 0.001) compared to high-volume hospitals. In-hospital LOS was 1.21 times longer at low-volume hospitals (aOR, 1.21; 95% CI, 1.20–1.22; p < 0.001) than at high-volume hospitals. In addition, the risk of in-hospital death was 1.22 times higher (aOR, 1.22; 95% CI, 1.12–1.33; p < 0.001) and the risk of 1-year death was 1.07 times higher (aOR, 1.07; 95% CI, 1.04–1.10; p < 0.001) at rural hospitals compared to urban hospitals.
Conclusions
Clinicians should focus on improving clinical outcomes for hip fracture patients in low-volume and rural hospital settings, with a specific emphasis on reducing mortality rates.
8.Tuberculous and Malignant Pleural Effusions With Adenosine Deaminase Levels of 40–70 IU/L: Trends in New Cases Over Time and Differentiation Between Groups
Jaehee LEE ; Jongmin PARK ; Jae Kwang LIM ; Ji Eun PARK ; Yong Hoon LEE ; Sun Ha CHOI ; Hyewon SEO ; Seung Soo YOO ; Shin Yup LEE ; Seung-Ick CHA ; Jae Yong PARK ; Chang Ho KIM
Journal of Korean Medical Science 2025;40(13):e35-
Background:
The diagnosis of tuberculous pleural effusion (TPE) often relies on pleural fluid adenosine deaminase (ADA) levels. The diagnostic utility of ADA, however, is influenced by the prevalence of tuberculosis (TB) in local populations. Malignant pleural effusion (MPE) cases can exhibit moderately elevated ADA levels comparable to those seen in TPE. As population aging potentially impacts ADA levels, global TB incidence is decreasing whereas the burden of malignancy is on the rise. Consequently, epidemiological shifts and temporal changes in ADA distribution complicate the differential diagnosis between TPE and MPE when ADA levels are within the 40–70 IU/L range. Nonetheless, data specific to this subset are scarce.
Methods:
This retrospective study included consecutive patients aged > 18 years with confirmed TPE and MPE, spanning from 2012 to 2023. ADA levels in pleural fluid were categorized into three groups: < 40 IU/L, 40–70 IU/L, and > 70 IU/L. The study examined annual trends in the frequency of new cases and ADA level distributions over time and identified discriminating factors between TPE and MPE in cases with ADA levels of 40–70 IU/L.
Results:
In total, 297 TPE and 369 MPE cases were included in this study. Over the study period, the frequency of TPE progressively declined, while that of MPE increased. In the most recent four-year period, new TPE and MPE cases with ADA levels of 40–70 IU/L occurred at comparable numbers. Multivariable analysis identified pleural fluid carcinoembryonic antigen (CEA) levels and the number of focal pleural nodules as independent predictors for MPE. Specifically, the presence of either CEA levels > 15.7 ng/mL or more than eight pleural nodules yielded the highest diagnostic accuracy with a sensitivity of 88%, specificity of 100%, and an area under the curve of 0.95.
Conclusion
The differential diagnosis between TPE and MPE with pleural ADA levels of 40–70 IU/L has become increasingly critical due to evolving epidemiological patterns and ADA distribution changes over time. Pleural fluid CEA levels and the characteristics of pleural nodules may offer valuable guidance in distinguishing between TPE and MPE within this diagnostic gray zone.
9.Appendicular Skeletal Muscle Mass to Visceral Fat Area Ratio Predicts Hepatic Morbidities
Eugene HAN ; Yong-ho LEE ; Sang Hoon AHN ; Bong-Soo CHA ; Seung Up KIM ; Byung-Wan LEE
Gut and Liver 2024;18(3):509-519
Background/Aims:
Reports on the association between sarcopenic visceral obesity and nonalcoholic fatty liver disease (NAFLD)-associated morbidities remain scarce. We investigated the association between sarcopenia and visceral obesity, and the influence of this association on hepatic and coronary comorbidities.
Methods:
The appendicular skeletal muscle mass to visceral fat area ratio (SV ratio) was evaluated using bioelectric impedance analysis. NAFLD and significant liver fibrosis were assessed using transient elastography, and high atherosclerotic cardiovascular disease (ASCVD) risk was defined as a 10-year ASCVD risk score >10%. Sarcopenia was defined as appendicular skeletal muscle mass adjusted by body mass index (<0.789 for men and <0.512 for women).
Results:
In total, 82.0% (n=1,205) of the entire study population had NAFLD, and 14.6% of these individuals (n=176) exhibited significant liver fibrosis. Individuals with the lowest SV ratio had a significantly increased risk of NAFLD, significant liver fibrosis, and high ASCVD risk (all p<0.05). Individuals with both the lowest SV ratio and sarcopenia had the highest risk of developing NAFLD (odds ratio [OR]=3.11), significant liver fibrosis (OR=2.03), and high ASCVD risk (OR=4.15), compared with those with a higher SV ratio and without sarcopenia (all p<0.05).
Conclusions
Low SV ratio combined with sarcopenia was significantly associated with an increased risk of NAFLD, significant liver fibrosis, and high ASCVD risk among individuals with a high risk of NAFLD.
10.Comparative Interrupted Time Series Analysis of Medical Expenses in Patients with Intertrochanteric Fracture Who Underwent Internal Fixation and Hemiarthroplasty
Seung-Hoon KIM ; Yonghan CHA ; Suk-Yong JANG ; Bo-Yeon KIM ; Hyo-Jung LEE ; Gui-Ok KIM
Hip & Pelvis 2024;36(2):144-154
Purpose:
The objective of this study was to assess postoperative direct medical expenses and medical utilization of elderly patients who underwent either hemiarthroplasty (HA) or internal fixation (IF) for treatment of a femoral intertrochanteric fracture and to analyze differences according to surgical methods and age groups.
Materials and Methods:
Data from the 2011 to 2018 Korean National Health Insurance Review & Assessment Service database were used. Risk-set matching was performed for selection of controls representing patients with the same sex, age, and year of surgery. A comparative interrupted time series analysis was performed for evaluation of differences in medical expenses and utilization between the two groups.
Results:
A total of 10,405 patients who underwent IF surgery and 10,405 control patients who underwent HA surgery were included. Medical expenses were 18% lower in the IF group compared to the HA group during the first year after the fracture (difference-in-difference [DID] estimate ratio 0.82, 95% confidence interval [CI] 0.77-0.87, P<0.001), and 9% lower in the second year (DID estimate ratio 0.91, 95% CI 0.85-0.99, P=0.018). Length of hospital stay was significantly shorter in the IF group compared to the HA group during the first two years after time zero in the age ≥80 group.
Conclusion
A noticeable increase in medical expenses was observed for patients who underwent HA for treatment of intertrochanteric fractures compared to those who underwent IF over a two-year period after surgery. Therefore, consideration of such findings is critical when designing healthcare policy support for management of intertrochanteric fractures.

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