• Journal of Preventive Medicine and Public Health
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• v.43 no.4
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• pp.330-340
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• 2010

Objectives: This study aims to evaluate and explain the socioeconomic inequalities of all-cause mortality after breast cancer surgery in South Korea. Methods: This population based study included all 8868 females who underwent radical mastectomy for breast cancer between January 2002 and June 2003. Follow-up for mortality continued from January 2002 to June 2006. The patients were divided into 4 socioeconomic classes according to their socioeconomic status as defined by the National Health Insurance contribution rate. The relationship between socioeconomic status and all-cause mortality after breast cancer surgery was assessed using the Cox proportional hazards model with adjusting for age, the Charlson’s index score, emergency hospitalization, the type of hospital and the hospital ownership. Results: Those in the lowest socioeconomic status group had a significantly higher hazard ratio of 2.09 (95% CI =1.50 - 2.91) compared with those in the highest socioeconomic group after controlling for all the identifiable confounding variables. For allcause mortality after radical mastectomy, all the other income groups showed significantly higher 3-year mortality rates than did the highest income group. Conclusions: The socioeconomic status of breast cancer patients should be considered as an independent prognostic factor that affects all-cause mortality after radical mastectomy, and this is possibly due to a delayed diagnosis, limited access or minimal treatment leading to higher mortality. This study may provide tangible support to intensify surveillance and treatment for breast cancer among low socioeconomic class women.

• Health Policy and Management
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• v.29 no.2
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• pp.237-244
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• 2019

Background: Weekend admission is known for having association with increased mortality attributed by poor quality of care and severe patients. We investigated the association between hospital admission on weekends and the in-hospital mortality rates of patients with cardiovascular disease. Furthermore, we examined this association stratified by admission via emergency room or not. Methods: We analyzed claim data provided by the Health Insurance Review & Assessment in 2013. In total, 80,817 cardiovascular patients were included in this study, which treated in-hospital mortality (early and during total length of stay) as a dependent variable. A generalized linear mixed effects model was used. We conducted subgroup analyses stratified by admission via emergency room or not. Results: Patients who admitted on weekend showed higher in-hospital mortality both early (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.23-1.78) and during total length of stay (OR, 1.17; 95% CI, 1.02-1.33) compared to those admitted on weekdays. Patients who were admitted to the hospital on a weekend by emergency room were more likely to experience early in-hospital mortality compared to those admitted on weekdays. Furthermore, we found that patients not admitted to the hospital through the emergency department were more likely to experience both early and total length of stay in-hospital mortality. Conclusion: Our study shows higher in-hospital mortality rates for cardiovascular patients admitted on weekends. Efforts to improve the quality of care on weekend are important to mitigate the 'weekend effect' and improve patient outcomes.

• Journal of Korean Society of Forest Science
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• v.113 no.2
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• pp.187-197
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• 2024

In this study, we aimed to identify the factors influencing post-fire mortality in Korean red pine (Pinus densiflora) using Cox's proportional hazards model and analyze the impact of these factors. We monitored the mortality rate of fire-damaged pine trees for seven years after a forest fire. Our survival analysis revealed that the risk of mortality increased with higher values of the delta normalized difference vegetation index (dNDVI), delat normalized burn ratio (dNBR), bark scorch index (BSI), bark scorch height (BSH) and slope. Conversely, the risk of mortality decreased with higher elevation, greater diameter at breast height (DBH), and higher value of delta moisture stress index (dMSI) (p < 0.01). Verification of the proportional hazards assumption for each variable showed that all factors, except slope aspect, were suitable for the model and significantly influenced fire occurrence. Among the variables, BSI caused the greatest change in the survival curves (p < 0.0001). The environmental change factors determined through remote sensing also significantly influenced the survival rates (p < 0.0001). These results will be useful in establishing restoration plans considering the potential mortality risk of Korean red pine after a forest fire.

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.845-873
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• 2008

This study estimates the VSL(value of a statistical life) as well as the WTP(willingness to pay) for mortality risk reduction using sample selection model with data on liver cancer examination which is associated with little possibility of multi-purpose(i.e. joint production) in averting behavior. The marginal benefits of mortality risk reduction are estimated by applying for household production function model with medical expense and the time required for medical examination of liver cancer. Individuals are more likely to take liver cancer test if they are male, older, higher educated, those with spouse, smoker, more income of household, and more anxious about their health. The costs of liver cancer examination are statistically significantly affected with expected signs by size of mortality risk reduction, sex, period of eduction, those with spouse, and household income. The marginal effect of mortality risk reduction owing to taking liver cancer examination is estimated at 321,097 won. The costs of liver cancer examination are increased by 905 won with more one year of education period and by 1,743 won with more one million won in household income. On liver cancer examination, male spends more 12,310 won than female and those with spouse pay more 7,969 won than those without spouse. Therefore the VSL from mortality risk reduction due to liver cancer examination is 321.10 million won at mean size of mortality risk reduction and mean cost of liver cancer examination. The results of sensitivity tests on costs and effects of liver cancer test shows that the VSLs are estimated in a range from 160.55 million won to 642.19 million won.

• Tuberculosis and Respiratory Diseases
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• v.81 no.3
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• pp.247-255
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• 2018

Background: Patients with acute respiratory failure secondary to tuberculous destroyed lung (TDL) have a poor prognosis. The aim of the present retrospective study was to develop a mortality prediction model for TDL patients who require mechanical ventilation. Methods: Data from consecutive TDL patients who had received mechanical ventilation at a single university-affiliated tertiary care hospital in Korea were reviewed. Binary logistic regression was used to identify factors predicting intensive care unit (ICU) mortality. A TDL on mechanical Ventilation (TDL-Vent) score was calculated by assigning points to variables according to ${\beta}$ coefficient values. Results: Data from 125 patients were reviewed. A total of 36 patients (29%) died during ICU admission. On the basis of multivariate analysis, the following factors were included in the TDL-Vent score: age ${\geq}65$ years, vasopressor use, and arterial partial pressure of oxygen/fraction of inspired oxygen ratio <180. In a second regression model, a modified score was then calculated by adding brain natriuretic peptide. For TDL-Vent scores 0 to 3, the 60-day mortality rates were 11%, 27%, 30%, and 77%, respectively (p<0.001). For modified TDL-Vent scores 0 to ${\geq}3$, the 60-day mortality rates were 0%, 21%, 33%, and 57%, respectively (p=0.001). For both the TDL-Vent score and the modified TDL-Vent score, the areas under the receiver operating characteristic curve were larger than that of other illness severity scores. Conclusion: The TDL-Vent model identifies TDL patients on mechanical ventilation with a high risk of mortality. Prospective validation studies in larger cohorts are now warranted.

• Environmental and Resource Economics Review
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• v.12 no.1
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• pp.49-74
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• 2003

This study used a slightly modified version of contingent valuation questionnaire designed and developed by Krupnick et al.(2000) to estimate the value of mortality risk reduction for environmental policy. Because that environmental policy, especially air pollution policy with some latency main effect on mortality risk reduction of old people with some latency period, respondents were asked about their current WTP for 5/1,000 mortality risk reduction being to take place beginning at 70 over the course of ten years. The annual mean WTP is 233,370 won (standard error 32,570 won) in spike/continuous/interval data model. The implied VSL is 466 million won. The 95% confidence interval is 339 million won~594 million won.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.554-563
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• 2006

Numerous epidemiological studies have shown stronger associations between $PM_{2.5}$ and both mortality and morbidity than $PM_{10}$. The association of $PM_{2.5}$ with respiratory mortality was examined in Seoul, during the period of $1996{\sim}2002$. Because $PM_{2.5}$ data were available for only 10% of this time period, a prediction regression model was developed to estimate $PM_{2.5}$ concentration. Death count due to respiratory-related diseases(total respiratory mortality; ICD-10, J00-J98) and death counts(cause-specific mortality) due to pneumonia(ICD-10, J12-J18), COPD(ICD-10, J40-J44) and asthma(ICD-10, J45-J46) were considered in this study. Averaged daily mortality was 5.6 for total respiratory mortality and 1.1 to 1.6 for cause-specific mortality. Generalized additive Poisson models controlling for confounders were used to evaluate the acute effects of particle exposures on total respiratory mortality and cause-specific mortality. An IQR increase in 5-day moving average of $PM_{2.5}(22.6{\mu}g/m^3)$ was associated with an 8.2%(95% CI: 4.5 to 12.1%) increase in total respiratory mortality The association of $PM_{2.5}$ was stronger for the elderly ($\geq$65 years old, 10.1%, 95% CI: 5.8 to 14.5%) and for males(8.9%, 95% CI: 2.1 to 11.3%). A $10{\mu}g/m^3$ increase in 5-day moving average of $PM_{2.5}$ was strongly associated with total respiratory mortality in winter(9.5%, 95% CI: 6.6 to 12.4%), followed by spring(3.1%, 95% CI: -1.2 to 7.5%), which was a different pattern with the finding in North American cities. However, our results are generally consistent with those observed in recent epidemiological studies, and suggest that $PM_{2.5}$ has a stronger effect on respiratory mortality in Seoul.

• Health Policy and Management
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• v.31 no.4
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• pp.462-471
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• 2021

Background: The purpose of this study was to identify the association between participation in social activities and mortality rates for those aged 45 aged and older in Korea. Methods: In this study, the 1st to 6th Korea Longitude Study of Aging was used to analyze 10,217 people excluding missing values among middle and old age groups aged 45 or older. The scope of social activities was classified into "religious gatherings," "religious gatherings," "leisure/cultural/sports-related organizations," and "clubs/hometowns/religious associations," and analyzed using a chi-square test and Cox proportional risk model. Results: In the case of non-participating groups in religious activities, the mortality rate was 1.24 times higher (hazard ratio [HR], 1.24; p=0.000) than those of the participating group. The non-participating group of social gatherings had a 1.27 times higher mortality rate (HR, 1.27; p<0.0001) than the participating group. In addition, the mortality rate of non-participating groups related to leisure/cultural/sports was 1.79 times higher (HR, 1.79; p=0.000). The mortality rate of the group that did not participate in the alumni association/festival/folklore society was 1.51 times higher than that of the participating group (HR, 1.51; p<0.0001). As a result of correcting the control variable to analyze the relationship between the number of participants in social activities and the mortality rate, the mortality rate of the group participating in one or less social activities was 2.26 times higher (HR, 2.26; p<0.0001) compared to the four or more social activity participating groups, and the mortality rate of the 1-3 social activities was 1.64 times higher (HR, 1.64; p<0.0001). Conclusion: As a result of the study, it was found that participation in social activities of the middle-aged and elderly groups was effective in reducing mortality, and in particular, it was found that there was a strong relationship with mortality in less than one social activity group. Therefore, it is intended to provide an academic basis for lowering the mortality rate of the group in line with the continuous improvement of domestic social activity participation conditions, and through this, this study can be expected to serve as a policy and institutional basis for lowering the mortality rate of the group.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.218-228
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• 2000

Background : Among 'structure', 'process' and 'outcome' approaches, outcome evaluation is considered as the most direct and best approach to assess the quality of health care providers. Risk-adjustment is an essential method to compare outcome across providers. This study has aims to judge performance of hospitals by severity adjusted mortality rates of coronary artery bypass graft (CABG) surgery. Methods : Medical records of 584 patients who got the CABG surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups was used to quantify severity of patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex. For evaluation of hospital performance, we calculated ratio of observed number to expected number of deaths and z score [(observed number of deaths - expected number of deaths)/square root of the variance in the number of deaths], and compared observed mortality rate with confidence interval of adjusted mortality rate for each hospital. Results : The overall in-hospital mortality was 7.0%, ranged from 2.7% to 15.7% by hospital. After severity adjustment the mortality by hospital was from 2.7% to 10.7%. One hospital with poor performance was distinctly divided from others with good performance. Conclusion : In conclusion, severity-adjusted mortality rate of CABG surgery might be applied as an indicator for hospital performance evaluation in Korea. But more pilot studies and improvement of methodologies has to be done to use it as quality indicator.

• Journal of Preventive Medicine and Public Health
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• v.39 no.6
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• pp.469-476
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• 2006

Objectives : To investigate the effect of parents' social class on infant and child mortality rates among the birth cohort, for the period of transition to and from the Koran economic crisis 1995-2004. Methods : All births reported to between 1995 and 2004 (n=5,711,337) were analyzed using a Cox regression model, to study the role of the social determinants of parents in infant and child mortality. The results were adjusted for the parents' age, education and occupation, together with mother's obstetrical history. Results. The crude death rate among those under 10 was 3.71 per 1000 births (21,217 deaths among 5,711,337 births) between 1995 and 2004. The birth cohorts from lower educated parents less than elementary school showed higher mortality rates compared with those from higher educated parents over university level (HR:3.0 (95%CI:2.8-3.7) for father and HR:3.4 (95%CI:3.3-4.5) for mother). The mother's education level showed a stronger relationship with mortality among the birth cohort than that of the fathers. The gaps in infant mortality rates by parents' social class, and educational level became wider from 1995 to 2004. In particular, the breadth of the existing gap between higher and lower parents' social class groups has dramatically widened since the economic crisis of 1998. Discussions : This study shows that social differences exist in infant and child mortality rates. Also, the gap for the infant mortality due to social class has become wider since the economic crisis of 1998.