• Title/Summary/Keyword: Cox's proportional hazard model

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Estimation of Survival Rates in Patients with Lung Cancer in West Azerbaijan, the Northwest of Iran

  • Abazari, Malek;Gholamnejad, Mahdia;Roshanaei, Ghodratollah;Abazari, Reza;Roosta, Yousef;Mahjub, Hossein
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.9
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    • pp.3923-3926
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    • 2015
  • Background: Lung cancer is a fatal malignancy with high mortality and short survival time. The aim of this study was to estimate survival rates of Iranian patients with lung cancer and its associate predictive factors. Materials and Methods: The study was conducted on 355 patients admitted to hospitals of West Azerbaijan in the year 2007. The patients were followed up by phone calls until the end of June 2014. The survival rate was estimated using the Kaplan-Meier method and log-rank test for comparison. The Cox's proportional hazard model was used to investigate the effect of various variables on patient survival time, including age, sex, Eastern Cooperative Oncology Group (ECOG) performance, smoking status, tumor type, tumor stage, treatment, metastasis, and blood hemoglobin concentration. Results: Of the 355 patients under study, 240 died and 115 were censored. The mean and median survival time of patients was 13 and 4.8 months, respectively. According to the results of Kaplan-Meier method, 1, 2, and 3 years survival rates were 39%, 18%, and 0.07%, respectively. Based on Cox regression analysis, the risk of death was associated with ECOG group V (1.83, 95% CI: 1 Conclusions: The survival time of the patients with lung cancer is very short. While early diagnosis may improve the life expectancy effective treatment is not available.

Crash Clearance Time Analysis of Korean Freeway Systems using a Cox Model (Cox 모형을 활용한 고속도로 사고 처리시간 영향인자 분석)

  • Chung, Younshik;Kim, Seon Jung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.6
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    • pp.1017-1023
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    • 2017
  • Duration induced by freeway crashes has a critical influence on traffic congestion. In general, crash duration composes detection and verification, response, and clearance time. Of these, the crash clearance time determined by a crash clearance team has attracted considerable attention in the freeway congestion management since the interest of the first two time stages faded away with increasing ubiquitous mobile phone users. The objective of this study is to identify the critical factors that affect freeway crash clearance time using a Cox's proportional hazard model. In total, 6,870 crash duration data collected from 30 major Korean freeways in 2013 were used. As a result, it was found that crashes during the night, with trailer or larger size truck, and in tunnel section contribute to increasing clearance time. Crashes associated with fatality, completed damage of crashed vehicle (s), and vehicles' fire or rollover after crash also lead to increasing clearance time. Additionally, an increase in the number of vehicles involved resulted in longer clearance time. On the other hand, crashes in the vicinity of tollgate, by passenger car, during spring, on flat section, and of car-facility type had longer clearance time. On the basis of the results, this paper suggested some strategic plans and mitigation measures to reduce crash clearance time on Korean freeway systems.

Clinical evaluation of 3.0-mm narrow-diameter implants: a retrospective study with up to 5 years of observation

  • InKyung Hwang;Tae-Il Kim;Young-Dan Cho
    • Journal of Periodontal and Implant Science
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    • v.54 no.1
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    • pp.44-52
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    • 2024
  • Purpose: This study aimed to evaluate the clinical outcomes of a single type of narrow-diameter implant (NDI) by investigating its survival rate and peri-implant marginal bone loss (MBL). In addition, variables possibly related to implant survival and MBL were investigated to identify potential risk factors. Methods: The study was conducted as a retrospective study involving 49 patients who had received 3.0-mm diameter TSIII implants (Osstem Implant Co.) at Seoul National University Dental Hospital. In total, 64 implants were included, and dental records and radiographic data were collected from 2017 to 2022. Kaplan-Meier survival curves and a Cox proportional hazard model were used to estimate the implant survival rate and to investigate the effects of age, sex, jaw, implant location, implant length, the stage of surgery, guided bone regeneration, type of implant placement, and the surgeon's proficiency (resident or professor) on implant survival. The MBL of the NDIs was measured, and the factors influencing MBL were evaluated. Results: The mean observation period was 30.5 months (interquartile range, 26.75-45 months), and 6 out of 64 implants failed. The survival rate of the NDIs was 90.6%, and the multivariate Cox regression analysis showed that age was associated with implant failure (hazard ratio, 1.17; 95% confidence interval, 1.04-1.31, P=0.01). The mean MBL was 0.44±0.75 mm, and no factors showed statistically significant associations with greater MBL. Conclusions: NDIs can be considered a primary alternative when standard-diameter implants are unsuitable. However, further studies are required to confirm their long-term stability.

Prognostic Value of Serum Ferritin in Terminally Ill Cancer Patients (말기암환자에서 예후인자로서 혈청 Ferritin의 유용성)

  • Lee, Soo Hee;Choi, Youn Seon;Hwang, In Cheol;Yeom, Chang Hwan;Lee, June Yeong
    • 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.

Association Between Socioeconomic Status and All-Cause Mortality After Breast Cancer Surgery: Nationwide Retrospective Cohort Study (사회경제적 위치와 유방암 수술 후 총 사망위험과의 관련성)

  • Park, Mi-Jin;Chung, Woo-Jin;Lee, Sun-Mi;Park, Jong-Hyock;Chang, Hoo-Sun
    • 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.

Risk Factor for Recurrence in Completely Resected Stage IB Non-small Cell Lung Cancer (완전 절제된 IB기 비소세포폐암에서 수술 후 재발의 위험 인자)

  • Seok, Yang-Ki;Lee, Eung-Bae
    • Journal of Chest Surgery
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    • v.40 no.10
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    • pp.680-684
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    • 2007
  • Background: Complete surgical resection is the most effective treatment for stage IB non-small cell lung cancer (NSCLC). Recurrence accounts for the disappointing survival rates after resection. There has been renewed interest in adjuvant therapy after complete resection. Appropriate selection of effective adjuvant therapy will depend on the prognostic factors for recurrence. Material and Method: The study included 114 patients with completely resected stage IB NSCLC. The variables selected for the study were gender, age, the type of resection, cell type, the degree of differentiation, the tumor size and the presence of visceral pleura invasion. The Kaplan-Meier method was used to estimate the survival and disease-free survival rate. The results were compared using the log rank test. Multivariate analysis was performed by Cox's proportional hazard model. Two-sided p-valves < 0.05 were considered to be statistically significant. Result: The 3-year overall survival and the disease-free survival rates were 87.0% and 79.4%, respectively. The degree of differentiation showed a significant influence on disease-free survival according to the univariate analysis. According to the multivariate analysis, a poor grade of differentiation was a significant poor prognostic factor. Conclusion: These results demonstrate that poor differentiation may be a poor prognostic factor for patients with completely resected IB NSCLC. Therefore, the patients with a poor grade of differentiation may require adjuvant therapies.

Prognostic Value of Leptin in Terminally Ill Cancer Patients (말기암환자의 여명 예측 요인, 혈중 렙틴 농도의 효과)

  • Hong, Ji-Hyun;Lee, So-Jin;Kwak, Sang-Mi;Choi, Youn-Seon;Lee, June-Yeong
    • 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.

A Study on the Determinants Affecting Employment of the Unemployed Disabled (장애인 실업자의 취업에 영향을 미치는 결정요인에 관한 연구)

  • Gang, B.S.;Yeum, D.M.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.9 no.2
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    • pp.115-120
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    • 2015
  • This study applied a cox proportional hazard model for analysis, using data of the Panel Survey of Employment for the Disable from the first to fifth years. The purpose of the study is to make a policy suggestion necessary for the support of employment for the disabled, by analyzing important factors affecting employment of the unemployed disabled according to the unemployment period. Results of the analysis were: a model that considered all the sociodemographic, obstructive and social environmental factors was verified; the higher subjective SES of the disabled, the higher employment rate of the unemployed disabled; compared to the severely disabled, the slightly disabled had more advantages for employment; and relatively the lower unearned income, the higher employment rate. This study suggested based on these results limitations and implications of the study.

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Prediction of Tumor Progression During Neoadjuvant Chemotherapy and Survival Outcome in Patients With Triple-Negative Breast Cancer

  • Heera Yoen;Soo-Yeon Kim;Dae-Won Lee;Han-Byoel Lee;Nariya Cho
    • Korean Journal of Radiology
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    • v.24 no.7
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    • pp.626-639
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    • 2023
  • Objective: To investigate the association of clinical, pathologic, and magnetic resonance imaging (MRI) variables with progressive disease (PD) during neoadjuvant chemotherapy (NAC) and distant metastasis-free survival (DMFS) in patients with triple-negative breast cancer (TNBC). Materials and Methods: This single-center retrospective study included 252 women with TNBC who underwent NAC between 2010 and 2019. Clinical, pathologic, and treatment data were collected. Two radiologists analyzed the pre-NAC MRI. After random allocation to the development and validation sets in a 2:1 ratio, we developed models to predict PD and DMFS using logistic regression and Cox proportional hazard regression, respectively, and validated them. Results: Among the 252 patients (age, 48.3 ± 10.7 years; 168 in the development set; 84 in the validation set), PD was occurred in 17 patients and 9 patients in the development and validation sets, respectively. In the clinical-pathologic-MRI model, the metaplastic histology (odds ratio [OR], 8.0; P = 0.032), Ki-67 index (OR, 1.02; P = 0.044), and subcutaneous edema (OR, 30.6; P = 0.004) were independently associated with PD in the development set. The clinical-pathologic-MRI model showed a higher area under the receiver-operating characteristic curve (AUC) than the clinical-pathologic model (AUC: 0.69 vs. 0.54; P = 0.017) for predicting PD in the validation set. Distant metastases occurred in 49 patients and 18 patients in the development and validation sets, respectively. Residual disease in both the breast and lymph nodes (hazard ratio [HR], 6.0; P = 0.005) and the presence of lymphovascular invasion (HR, 3.3; P < 0.001) were independently associated with DMFS. The model consisting of these pathologic variables showed a Harrell's C-index of 0.86 in the validation set. Conclusion: The clinical-pathologic-MRI model, which considered subcutaneous edema observed using MRI, performed better than the clinical-pathologic model for predicting PD. However, MRI did not independently contribute to the prediction of DMFS.

Cohort Study on the Association between Alcohol Consumption and the Risk of Colorectal Cancer in the Korean Elderly (노인인구에서 음주와 대장직장암 발생간의 연관성에 관한 코호트연구)

  • Lim, Hoi-Jeong;Park, Byung-Joo
    • Journal of Preventive Medicine and Public Health
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    • v.41 no.1
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    • pp.23-29
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    • 2008
  • Objectives : We examined the association between alcohol consumption and incidence of colorectal cancer in elderly Koreans. Methods : The cohort members (n=14,304) consisted of 4,834 males and 9,470 females derived from the Korea Elderly Pharmacoepidemiologic Cohort (KEPEC), a population-based dynamic cohort. They were aged 65 years old or older and lived in Busan between 1993-1998; they were beneficiaries of the Korean Medical Insurance Corporation (KMIC). Baseline information was surveyed by a self-administered, mailed questionnaire. This study population was restricted to 14,304 participants who reported alcohol drinking habits on the questionnaire and had not been diagnosed with colorectal cancer at baseline. The adjusted hazard ratios (aHR) of status, type, frequency and daily average amount of alcohol consumption were computed with Cox's proportional hazard model, with the never-drinkers as a reference group and controlling for age and gender. Results : After 4.82 person-years of mean follow-up 112 cases of colorectal cancer occurred. The incidence densities of colorectal cancer were 161 (95% CI=123-200) for never-drinkers, 219 (95% CI=125-339) for ex-drinkers, and 137 (95% CI=84-189) for current-drinkers per 100,000 person-year. The status, type, frequency, and daily average amount of alcohol consumption were not significantly related to the incidence of colorectal cancer after controlling for age and gender. Conclusions : There was no significant association between alcohol consumption and colorectal cancer among elderly people after controlling for age and gender.