• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6773-6777
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• 2015

We used to LASSO-Cox method for determining prognostic factors of male breast cancer survival and showed the superiority of this method compared to Cox proportional hazard model in low sample size setting. In order to identify and estimate exactly the relative hazard of the most important factors effective for the survival duration of male breast cancer, the LASSO-Cox method has been used. Our data includes the information of male breast cancer patients in Fars province, south of Iran, from 1989 to 2008. Cox proportional hazard and LASSO-Cox models were fitted for 20 classified variables. To reduce the impact of missing data, the multiple imputation method was used 20 times through the Markov chain Mont Carlo method and the results were combined with Rubin's rules. In 50 patients, the age at diagnosis was 59.6 (SD=12.8) years with a minimum of 34 and maximum of 84 years and the mean of survival time was 62 months. Three, 5 and 10 year survival were 92%, 77% and 26%, respectively. Using the LASSO-Cox method led to eliminating 8 low effect variables and also decreased the standard error by 2.5 to 7 times. The relative efficiency of LASSO-Cox method compared with the Cox proportional hazard method was calculated as 22.39. The19 years follow of male breast cancer patients show that the age, having a history of alcohol use, nipple discharge, laterality, histological grade and duration of symptoms were the most important variables that have played an effective role in the patient's survival. In such situations, estimating the coefficients by LASSO-Cox method will be more efficient than the Cox's proportional hazard method.

• The Korean Journal of Applied Statistics
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• v.15 no.2
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• pp.233-250
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• 2002

Cox's proportional hazard model is highly-used for the regression analysis of survival data in various fields. Regression diagnostics for the proportional hazards model, however, is not as well-known as the diagnostics for the classical linear models and so these diagnostic methods are not used widely in our practical data analyses. For this reason, we review the residuals proposed by several authors, and investigate how to use them in assessing the model. We also provide the results and interpretation with the analysis of PBC data using S-plus 2000 program.

• Journal of Korea Planning Association
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• v.54 no.2
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• pp.5-16
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• 2019

The purpose of this study is to analyze the spatial characteristics of business-type-changed parcel in the Hongik-University commercial area, from the view point of commercial gentrification. A commercial gentrification occurs through a business-type-change in a spatial basic unit (microscopic spatial unit such as parcel) of an area which has not been considered in relavent policies and research. So, this study analyzed the spatial characteristics of business-type-changed parcels using the Cox's proportional hazard regression model. The main results of this study are as follows. First, as new developments in the adjacent area occur, the business-type-change probability increases. Second, by the commercial area division, the business-type-change probability is different. Finally, the accessibility is better, the probability is higher. These results could suggest that a consideration of the spatial characteristics form microscopic viewpoint is necessary to understand the commercial gentrification. And these could be used as basic data for a gentrification diagnostic and management system, which can predict gentrification from the view point of business-type-change on the basis of a parcel.

• Annals of dermatology
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• v.30 no.6
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• pp.668-675
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• 2018

Background: Drug survival, defined as the time until discontinuation, is a parameter reflecting real-world therapeutic effectiveness. Few studies have examined the influence of economic factors on the drug survival of biologic agents for psoriasis, particularly in Asian countries. Objective: To determine the drug survival for ustekinumab in real-life settings and investigate the factors affecting drug survival for psoriasis patients in Korea. Methods: We evaluated 98 psoriasis patients who were treated with ustekinumab at a single center. We analyzed the efficacy and drug survival of ustekinumab. Cox proportional hazard analysis and competing risk regression analysis were performed to reveal the factors affecting the drug survival of ustekinumab. Results: The overall mean drug survival was 1,596 days (95% confidence interval [CI], 904~2,288). Among the 39 cessations of ustekinumab treatment, 9 (23.1%) patients discontinued treatment after experiencing satisfactory results. Multivariate Cox proportional hazard analysis revealed that paying on patients' own expense was the major predictor for the discontinuation of ustekinumab (hazard ratio [HR], 9.696; 95% CI, 4.088~22.998). Competing risk regression analysis modeling of discontinuation because of factors other than satisfaction of an event also revealed that ustekinumab treatment at the patient's expense (HR, 4.138; 95% CI, 1.684~10.168) was a predictor of discontinuation rather than satisfaction. Conclusion: The results of our study revealed that the cost of biologics treatment affects the drug survival of ustekinumab and suggested that economic factors affect the drug survival of ustekinumab treatment in Korea.

• Korean Journal of Social Welfare
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• v.59 no.1
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• pp.301-327
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• 2007

The purpose of this study is to examine the timing and the risk factors associated with the adoption of legally-free foster children. The sample of the study was drawn from foster care files of Adoption and Foster Care Analysis and Reporting System(AFCARS) in 32 states between October 1998 (FY 1999) and September 2002(FY 2002). The timing post-TPR to adoption was examined by plotting the Kaplan-Meier cumulative hazard function for adoption and by plotting the KM hazard functions stratified by child's race and child's age at TPR. Cox proportional-hazards regression analysis was used to identify risk factors for adoption of legally-free foster children after TPR. The hazard of adoption was very low immediately after TPR but increased steadily starting at 3 months and then declined after 20 months. The cumulative hazard functions for White non-Hispanic children and Black non-Hispanic children crossed over at 13 months after TPR. Racial minority status, older age, and disability were negatively associated with the hazard of adoption. Physical abuse, sexual abuse had the lower hazard for adoption compared by neglect. Caretaker's inability to cope had the slightly lower hazard for adoption whereas inadequate housing showed the slightly greater hazard for adoption. Characteristics of foster care services turned into be powerful predictors of adoption. Specifically, legally-free children placed in pre-adoptive homes, those who shared the same racial/ethnic background with their foster caretakers, and those who were placed in two-parent families have a greater likelihood of adoption. The findings highlight the importance of foster care service provisions after TPR to facilitate adoption of legally-free foster children. Furthermore, a more substantial resources and targeted support for foster children who experience physical abuse and sexual abuse in need of adoption should be provided for moving the foster children into permanency.

• Journal of the Korean Data and Information Science Society
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• v.23 no.2
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• pp.257-269
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• 2012

Global crisis expedites the change in the environment of industry and puts small size enterprises in danger of mass bankruptcy. Because of this, domestic small size enterprises is an urgent need of restructuring. Based on the small business data registered in the Credit Guarantee Fund, we estimated the survival probability in the context of the survival analysis. We also analyzed the survival time which are distinguished depending on the types of business in the small business. Financial variables were also conducted using COX regression analysis of small businesses by types of business. In terms of types of business wholesale and retail trade industry and services were relatively high in the survival probability than light, heavy, and the construction industries. Especially the construction industry showed the lowest survival probability. In addition, we found that construction industry, the bigger BIS (bank of international settlements capital ratio) and current ratio are, the smaller default-rate is. But the bigger borrowing bond is, the bigger default-rate is. In the light industry, the bigger BIS and ROA (return on assets) are, the smaller a default-rate is. In the wholesale and retail trade industry, the bigger bis and current ratio are, the smaller a default-rate is. In the heavy industry, the bigger BIS, ROA, current ratio are, the smaller default-rate is. Finally, in the services industry, the bigger current ratio is, the smaller a default-rate is.

• Journal of agricultural medicine and community health
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• v.32 no.1
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• pp.13-26
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• 2007

Objectives: This study was conducted to investigate the association between health risk factors and mortality in Juam cohort. Methods: The subjects were 1,447 males and 1,889 females who had been followed up for 68.5 months to 1 January 2001. Whether they were alive or not was confirmed by the mortality data of the National Statistical Office. A total of 289 persons among them died during the follow-up period. The Cox's proportional hazard regression model was used for survival analysis. Results: Age, type of medical insurance, self cognitive health level, habit of alcohol drinking, smoking, exercise and BMI level were included in Cox's proportional hazard model by gender. The hazard ratio of age was 1.07(95% CI: 1.05-1.10) in men, 1.09(95% CI: 1.06-1.12) in women. The hazard ratio of medical aid(lower socioeconomic state) was 1.43(95% CI 1.02-2.19) in women. The hazard ratios of current alcohol drinking and current smoking were respectively 1.69(95% CI: 1.01-2.98), 1.52(95% CI: 1.02-2.28) in women. The hazard ratio of underweight was 1.56(95% CI 1.08-2.47) in men. The hazard ratios of underweight, normoweight, overweight, and obesity were respectively 1.63(95% CI: 1.02-2.67), 1.0(referent), 0.62(95% CI: 0.32-1.63), 1.27(95% CI: 0.65-3.06), which supported the U-shaped relationship between body mass index and mortality among the men over 65. Conclusions: The health risk factors increasing mortality were age, underweight in male, age, lower socioeconomic state, current alcohol drinking, current smoking in female. To evaluate long-term association between health risk factors and mortality, further studies need to be carried out.

• Journal of Hospice and Palliative Care
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• v.18 no.1
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• pp.51-59
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• 2015

Purpose: Predicting life expectancy of terminally ill cancer patients is very important. In many studies, ferritin is detected at higher levels in the sera of cancer patients, and higher ferritin level correlates with aggressiveness of disease and poor outcomes of patients. This study evaluated a prognostic role of serum ferritin levels in terminally ill cancer patients. Methods: This study enrolled 65 terminally ill cancer patients from March through June 2012. We assessed routine laboratory findings including serum ferritin levels as well as demographic and clinical characteristics of the patients. To examine the association between serum ferritin levels and patient's characteristics, we used Spearman's correlation analysis, Wilcoxon's rank sum test or Kruskal-Wallis test, as appropriately. For multivariate analysis, Cox's proportional hazard regression model was used to evaluate significance of serum ferritin levels as a prognostic factor. Results: A negative correlation between serum ferritin levels and survival time was found. After adjusting for sex, age, performance status, creatinine levels and white blood cell counts, serum ferritin levels were significantly associated with survival time. Conclusion: Even at the very end of life of terminal cancer patients, serum ferritin levels were an independent prognostic factor for survival.

• Journal of Hospice and Palliative Care
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• v.15 no.2
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• pp.99-107
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• 2012

Purpose: Most terminally ill cancer patients die from cancer anorexia-cachexia syndrome. This study evaluated a prognostic role of plasma leptin levels in terminally ill cancer patients. Methods: This study enrolled 69 terminally ill cancer patients who were aged above 20 years old from July 2009 to July 2010. For univariate analysis, an association between leptin levels and patient's characteristics or other variables was examined using Spearman's correlation analysis, Wilcoxon's rank-sum test or Kruskal-Wallis test, as appropriately. For multivariable analysis, Cox's proportional hazard regression model was used to evaluate a clinical significance of plasma leptin levels as a prognostic factor and to determine factors which affect the risk of death in terminally ill cancer patients. Results: A statistically significant positive correlation between plasma leptin levels and survival time was found. Univariate Cox's proportional hazard regression analyses also showed a moderately significant association between plasma leptin levels and survival time. However, after adjusting variables for sex, white blood cell counts, total bilirubin, AST, ALT, albumin and CRP levels, plasma leptin levels were not significantly associated with survival time. Conclusion: No significant association was found between plasma leptin levels and survival time in terminally ill cancer patients. However, this study suggested a prognostic value of plasma leptin levels in gastrointestinal cancer patients.

• Journal of Korean society of Dental Hygiene
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• v.21 no.2
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• pp.119-128
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• 2021

Objectives: The aim of this study was to investigate the effect of breastfeeding on the occurrence of early childhood caries in Korean infants and toddlers. Methods: Data on oral examinations of infants and toddlers of the National Health Insurance Service were analyzed. The study subjects were children who participated in both the first, second, and third oral examinations and the first general health examination in 2008-2017 (n=142,185). Based on the responses to the questionnaire, the subjects were classified into breastfeeding, formula feeding, and mixed feeding groups. The participants were monitored for the development of early childhood caries in three sequential oral examinations. Results: Based on the oral examination results conducted at 54-65 months old, the decayed-filled teeth index of the breastfeeding group was the highest (2.03±3.08), followed by the mixed (1.96±3.03) and the formula feeding groups (1.82±2.91). The Cox proportional hazard regression model including all the variables showed that the risk of developing dental caries was significantly lower in the formula (hazard ratio [HR], 0.85) and mixed feeding groups (HR, 0.91) than in the breastfeeding group. Conclusions: Breastfeeding children have a higher risk of early childhood caries; therefore, oral hygiene education and regular dental check-ups are necessary.