• Journal of Technology Innovation
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• v.26 no.4
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• pp.98-121
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• 2018

This article analyzes the survival of Korean software firms from 1995 to 2015 by Cox regression model and product-limit method. The results show that survival rates are different for each sector: IT service, package software, game software and internet service. In addition, firm growth and investment in research and development positively affect software firm's survival, while slack resources negatively affect the software firm's survival. The implication of this study is that characteristics of the software industry and technologies should be taken into consideration in survival strategy of software firms and government policy. Previous research on survival analysis has been mainly conducted in the manufacturing industry or at the special circumstance such as the foreign exchange crisis of Korea in the late 1990s. The contribution of this study is that expanding the survival analysis to software firms in Korea which are becoming more important recently.

• Journal of Korean Neurosurgical Society
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• v.65 no.4
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• pp.507-513
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• 2022

Objective : The goal of the following statewide age and gender-coordinated cohort study in Korea is to find out if there is a link between acute myocardial infarction (AMI) and Parkinson's disease (PD). Methods : Utilizing the National Health Insurance Sharing Service cohort, patient data were collected. Six thousand four hundred seventy-five individuals with PD were distinguished by utilizing the International Classification of Diseases 10 code G20 and have enrolled in the PD group. The number of participants decreased to 5259 after excluding 1039 patients who were hospitalized less than one time or who visited an outpatient clinic less than twice. Then, 26295 individuals were selected as part of the control group after case control matching was conducted through 1 : 5 age- and gender-coordinated matching. The Cox proportional hazard regression analysis and Kaplan-Meier method were utilized to analyze the likelihood of AMI in PD. Results : After controlling for age and gender, the hazard ratio of AMI in the PD group was 3.603 (95% confidence interval [CI], 2.837-4.577). After that, the following hazard ratio of AMI in the PD group was modified against for co-morbid medical disorders, resulting in 3.551 (95% CI, 2.795-4.511). According to a subgroup analysis, in males and females aged <65 and aged ≥65 and in the non-diabetes and diabetes, hypertension and non-hypertension, dyslipidemia and non-dyslipidemia subgroups, the AMI incidence rates were dramatically higher in the PD group compared to that of the control. Conclusion : Individuals with PD have a greater chance of AMI, according to this cross-national study.

• Korean Journal of Social Welfare Studies
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• v.40 no.1
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• pp.115-138
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• 2009

The primary focus of this study is to examine the characteristics of the asset poor and to empirically investigate those factors affecting the likelihood of the asset poor's poverty exit and entry. The 2nd wave through 8th wave data from KLIPS were used for analysis. The asset poverty lined of 50% of the household net asset was set up so that households below 50% are classified as the asset poor. The characteristics of the asset poor were examined in a static manner by analyzing only the 8th wave KLIPS data. To investigate those factors affecting the likelihood of asset poor's poverty transferal with a dynamic perspective, the authors employed two survival analysis methods, the life table analysis and the Time-dependent Cox regression analysis. Based on the findings, some recommendations were made for future policy efforts to support the asset poor and for the current poverty policies as well. In specific, if the 'Individual Development Account' is to be initiated in the future, it would be essential to build a systematic model to utilize accumulated asset by enhancing job competencies and ability to gain a decent job.

• Journal of Hospice and Palliative Care
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• v.5 no.2
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• pp.111-124
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• 2002

Purpose : Although the average life expectancy has increased due to advances in medicine, mortality due to cancer is on an increasing trend. Consequently, the number of terminally ill cancer patients is also on the rise. Predicting the survival period is an important issue in the treatment of terminally ill cancer patients since the choice of treatment would vary significantly by the patents, their families, and physicians according to the expected survival. Therefore, we investigated the prognostic factors for increased mortality risk in terminally ill cancer patients to help treat these patients by predicting the survival period. Methods : We investigated 31 clinical parameters in 157 terminally ill cancer patients admitted to in the Department of Family Medicine, National Health Insurance Corporation Ilsan Hospital between July 1, 2000 and August 31, 2001. We confirmed the patients' survival as of October 31, 2001 based on medical records and personal data. The survival rates and median survival times were estimated by the Kaplan-Meier method and Log-rank test was used to compare the differences between the survival rates according to each clinical parameter. Cox's proportional hazard model was used to determine the most predictive subset from the prognostic factors among many clinical parameters which affect the risk of death. We predicted the mean, median, the first quartile value and third quartile value of the expected lifetimes by Weibull proportional hazard regression model. Results : Out of 157 patients, 79 were male (50.3%). The mean age was $65.1{\pm}13.0$ years in males and was $64.3{\pm}13.7$ years in females. The most prevalent cancer was gastric cancer (36 patients, 22.9%), followed by lung cancer (27, 17.2%), and cervical cancer (20, 12.7%). The survival time decreased with to the following factors; mental change, anorexia, hypotension, poor performance status, leukocytosis, neutrophilia, elevated serum creatinine level, hypoalbuminemia, hyperbilirubinemia, elevated SGPT, prolonged prothrombin time (PT), prolonged activated partial thromboplastin time (aPTT), hyponatremia, and hyperkalemia. Among these factors, poor performance status, neutrophilia, prolonged PT and aPTT were significant prognostic factors of death risk in these patients according to the results of Cox's proportional hazard model. We predicted that the median life expectancy was 3.0 days when all of the above 4 factors were present, $5.7{\sim}8.2$ days when 3 of these 4 factors were present, $11.4{\sim}20.0$ days when 2 of the 4 were present, and $27.9{\sim}40.0$ when 1 of the 4 was present, and 77 days when none of these 4 factors were present. Conclusions : In terminally ill cancer patients, we found that the prognostic factors related to reduced survival time were poor performance status, neutrophilia, prolonged PT and prolonged am. The four prognostic factors enabled the prediction of life expectancy in terminally ill cancer patients.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.630-642
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• 1997

The purpose of this study was to examine the mortality risk associated with cognitive impairment among the rural elderly. The subjective of study was 558 of 'A Study on the Depression and Cognitive Impairment in the Rural Elderly' of Jung Ae Rhee and Hyang Gyun Jung's study(1993). Cognitive impairment and other social and health factors were assessed in 558 elderly rural community residents. For this study, a Korean version of the Mini-Mental State Examination(MMSEK) was used as a global indicator of cognitive functioning. And mortality risk factors for each cognitive impairment subgroup were identified by univariate and multivariate Cox regression analysis. At baseline 22.6% of the sample were mildly impaired and 14.2% were severely impaired. As the age increased, the cognitive function was more impaired. Sexual difference was existed in the cognitive function level. Also the variables such as smoking habits, physical disorders had the significant relationship with cognitive function impairment. Across a 3-year observation period the mortality rate was 8.5% for the cognitively unimpaired, 11.1% for the mildly impaired, and 16.5% for the severly impaired respendents. And the survival probability was .92 for the cognitively unimpaired, .90 for the mildly impaired, and .86 for the severly impaired respondents. Compared to survival curve for the cognitively unimpaired group, each survival curve for the mildly and the severely impaired group was not significantly different. When adjustments models were not made for the effects of other health and social covariates, each hazard ratio of death of mildly and severely impaired persons was not significantly different as compared with the cognitively unimpaired. But, as MMSEK score increased, significantly hazard ratio of death decreased. Employing Cox univariate proportional hazards model, statistically other significant variables were age, monthly income, smoking habits, physical disorders. Also when adjustments were made for the effects of other health and social covariates, there was no difference in hazard ratio of death between those with severe or mild impairment and unimpaired persons. And as MMSEK score increased, significantly hazard ratio of death did not decrease. Employing Cox multivariate proportional hazards model, statistically other significant variables were age, monthly income, physical disorders. Employing Cox multivariate proportional hazards model by sex, at men and women statistically significant variable was only age. For both men and women, also cognitive impairment was not a significant risk factor. Other investigators have found that cognitive impairment is a significant predictor of mortality. But we didn't find that it is a significant predictor of mortality. Even though the conclusions of our study were not related to cognitive impairment and mortality, early detection of impaired cognition and attention to associated health problems could improve the quality of life of these older adults and perhaps extend their survival.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.845-855
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• 2000

As high as 50% of pregnancies are known to fail and the majority of such losses occur during the peri-implantation period. For the establishment of pregnancy in mammalian species, therefore, implantation of the conceptus to the maternal endometrium must be completed successfully. Physiological events associated with implantation differ among mammals. In ruminant ungulates, an elongation of the trophohlast in early conceptus development is required before the attachment of the conceptus to the uterine endometrium. Moreover, implantation sites are restricted to each uterine caruncula where tissue remodeling, feto-maternal cell fusion and placentation take place in a coordinated manner. These unique events occur under strict conditions and are regulated by numerous factors from the uterine endometrium and trophoblast in a spatial manner. Interferon-tau (IFN-${\tau}$), a conceptus-derived anti-Iuteolytic factor, which rescues corpus luteum from its regression in ruminants, is particularly apt to play an important role as a local regulator in coordination with other factors, such as TGF-${\beta}$, Cox-2 and MMPs at the attachment and placentation sites.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.391-394
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• 2012

Aim: Depression is thought to be a predictor of poor survival among cancer patients. In our study, we aimed to investigate the association between depression and survival in patients with gastric cancer. Methods: The subjects were a total of 300 patients aged 20-75 years who had histological confirmed diagnosis of gastric cancer from January 2004 to May 2006. Three months after patients diagnosis, depression was scored using by the Depression Status Inventory (DSI) designed by Willian WK Zung. The follow-up period consisted of a total of 13,643 person-months. A Cox's regression analysis was used to assess the association between depression and survival. Results: The percentage of subjects with depression according to the DSI depression criteria was 31%. Tumor stage and treatment methods were significantly associated with depression of patients. Age (60 years or older), annual income, tumor stage, lymph nodes metastasis and treatment were significantly associated with increased hazard ratio (HR) for gastric cancer survival. The adjusted HR for mortality risk in gastric cancer patients with depression tended to be high (HR=3.34, 95% CI=1.23-5.49) and a significant trend was found (P<0.05). Conclusion: The data obtained in this prospective study in Chinese support the hypothesis that depression is associated with poor survival among gastric cancer patients. Further studies with a large sample and longer term follow-up period are needed.

• Korean Journal of Community Nutrition
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• v.25 no.1
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• pp.61-70
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• 2020

Objectives: This study examined the association of the total diet quality with the incidence risk of metabolic syndrome constituents and metabolic syndrome among Korean adults. Methods: Based on a community-based cohort of the Korean Genome and Epidemiology Study (KoGES) from 2001 to 2014, data from a total of 5,549 subjects (2,805 men & 2,744 women) aged 40~69 years at the baseline with a total follow-up period of 38,166 person-years were analyzed. The criteria of the National Cholesterol Education Program Adult Treatment Panel was employed to define metabolic syndrome. The total diet quality was estimated using the Korean Healthy Eating Index (KHEI). Hazard ratios (HR) and 95% confidence intervals (CI) for risk of metabolic syndrome constituents and metabolic syndrome in relation to KHEI quintile groups was calculated by multivariate Cox proportional hazards regression model. Results: After adjusting for age, energy intake, income, education, physical activity, smoking, and drinking, the incidence of abdominal obesity and high blood pressure was significantly lower, by approximately 29.7% (P < 0.01) and 25.2% (P < 0.01), respectively, in the fifth KHEI quintile compared to the first quintile in men. A significant decreasing trend of the metabolic syndrome incidence was observed across the improving levels of KHEI (HRq5vs.q1: 0.775, 95% CIq5vs.q1: 0.619~0.971, P for trend < 0.01). In women, the incidence of abdominal obesity and metabolic syndrome was significantly lower, by approximately 29.8% (P < 0.01) and 22.5% (P < 0.05), respectively, in the fifth KHEI quintile compared to the first quintile adjusting for multiple covariates. On the other hand, the linear trend of metabolic syndrome risk across the KHEI levels did not reach the significance level. Conclusions: A better diet quality can prevent future metabolic syndrome and its certain risk factors among Korean men and women.

• Journal of Preventive Medicine and Public Health
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• v.50 no.5
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• pp.328-335
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• 2017

Objectives: The prevalence of underweight in children under 5 years of age is anomalously high in Konawe District, Southeast Sulawesi Province, Indonesia. This state of affairs may be related to poor housing conditions, such as limited access to clean water, the absence of a sanitary latrine, and the use of poor housing materials. Therefore, this study aimed to examine the effect of housing conditions on underweight in under-5 children in Konawe District. Methods: This study was conducted in 2013 in 5 health centres in Konawe District, Southeast Sulawesi Province, and used a case-control study design. The study recruited 400 under-5 children, including 100 of whom were cases and 300 of whom were age-matched controls (1:3). Cases were underweight children, while the controls were children with a normal nutritional status. The independent variables were the availability and types of water and latrine facilities and housing materials (roof, wall, and floor). The statistical analysis used Cox regression. Results: A lack of water availability (odds ratio [OR], 5.0; 95% confidence interval [CI], 2.7 to 9.5; p<0.001), a lack of latrine availability in the home (OR, 2.5; 95% CI, 1.5 to 4.0; p<0.001), and poor-quality roofing materials (OR, 1.7; 95% CI, 1.1 to 2.7; p<0.02) significantly contributed to underweight in children. In contrast, the walls and the floors did not contribute to under-5 year children being underweight (p=0.09 and p=0.71, respectively). Conclusions: Sanitation facilities and roofing were identified as important factors to address in order to improve children's nutritional status. Children's health status was directly impacted by food intake via their nutritional status.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10231-10236
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• 2015

This study aimed to evaluate the prevalence of preoperative thrombocytosis and its prognostic significance in Thai patients with endometrial cancer. We retrospectively reviewed the medical records of 238 cases who had undergone surgical staging procedures between January 2005 and December 2008. Associations between clinicopathological variables and preoperative platelet counts were analyzed using Pearson's chi square or two-tailed Fisher's exact tests. Survival analysis was performed with Kaplan-Meier estimates. Univariate and Cox-regression models were used to evaluate the prognostic impact of various factors including platelet count in terms of disease-free survival and overall survival. The mean preoperative platelet count was $315,437/{\mu}L$ (SD $100,167/{\mu}L$). Patients who had advanced stage, adnexal involvement, lymph node metastasis, and positive peritoneal cytology had significantly higher mean preoperative platelet counts when compared with those who had not. We found thrombocytosis (platelet count greater than $400,000/{\mu}L$) in 18.1% of our patients with endometrial cancer. These had significant higher rates of advanced stage, cervical involvement, adnexal involvement, positive peritoneal cytology, and lymph node involvement than patients with a normal pretreatment platelet count. The 5-year disease-free survival and overall survival were significantly lower in patients who had thrombocytosis compared with those who had not (67.4% vs. 85.1%, p=0.001 and 86.0% vs. 94.9%, p=0.034, respectively). Thrombocytosis was shown to be a prognostic factor in the univariate but not the multivariate analysis. In conclusion, presence of thrombocytosis is not uncommon in endometrial cancer and may reflect unfavorable prognostic factors but its prognostic impact on survival needs to be clarified in further studies.