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

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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.

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.

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.

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.

The Relationship between the Cognitive Impairment and Mortality in the Rural Elderly (농촌지역 노인들의 인지기능 장애와 사망과의 관련성)

  • Sun, Byeong-Hwan;Park, Kyeong-Soo;Na, Baeg-Ju;Park, Yo-Seop;Nam, Hae-Sung;Shin, Jun-Ho;Sohn, Seok-Joon;Rhee, Jung-Ae
    • 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.

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Targeting Risk Factors for the Control of Central Line-Associated Bloodstream Infection in the Neonatal Intensive Care Unit: A Single Tertiary Center Experience

  • Jeong, Jiyoon;Kwun, Yoojin;Kim, Min-ju;Choi, Sang-Ho;Jung, Euiseok;Lee, Byong Sop;Kim, Ki-Soo;Kim, Ellen Ai-Rhan
    • Neonatal Medicine
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    • v.28 no.3
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    • pp.116-123
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    • 2021
  • Purpose: The aim of this study was to estimate the effect of targeting risk factors for the control of central line-associated bloodstream infection (CLABSI) among high-risk infants in a tertiary neonatal intensive care unit (NICU). Methods: Infants admitted to the NICU and diagnosed with CLABSI from January to December 2013 were eligible for inclusion to the study. The CLABSI group (n=47) was matched in a 1:2 ratio to the control group (n=94) based on gestational age, birth weight, and Score for Neonatal Acute Physiology-II. Risk factors for CLABSI were identified using the Cox proportional hazard model, and analysis of the effect of these risk factors targeting infection control was performed. Results: The risk factors associated with CLABSI were prolonged central line dwell days (adjusted hazard ratio [HR], 1.028; 95% confidence interval [CI], 1.011 to 1.045; P=0.001), use of a silicone catheter (adjusted HR, 5.895; 95% CI, 1.893 to 18.355; P=0.002), surgical treatment (adjusted HR, 3.793; 95% CI, 1.467 to 9.805; P=0.006), and less probiotic supplementation (adjusted HR, 0.254; 95% CI, 0.068 to 0.949; P=0.042). By targeting these risk factors with a quality improvement initiative, the mean CLABSI incidence rate per 1,000 catheter-days decreased from 6.6 to 3.1 (P=0.004). Conclusion: Targeting risk factors for infection control significantly reduced the rate of CLABSI among high-risk infants in the NICU.