• Title/Summary/Keyword: Cox regression hazard model

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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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China's Brain Gain at the High End: An Assessment of Thousand Youth Talents Program

  • Sun, Yutao;Guo, Rongyu;Zhang, Shuai
    • Asian Journal of Innovation and Policy
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    • v.6 no.3
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    • pp.274-294
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    • 2017
  • While studies have viewed the effect of Chinese talent-attracting programs launched by government since reform and open door policy, little of them has assessed these programs empirically and pertinently. This article intends to assess an important program - the Thousand Youth Talents Program (TYTP). Frist, this paper proposed a transnational migration matrix of the academics to clarify the dynamic mechanism of academic brain gain at the high end. Then, the Kaplan-Meier analysis and Cox regression model are used to empirically analyze the policy effect of TYTP. The results show that, academic ability have double edged impacts on brain gain at the high end, some scholars whose last employer's academic ranking is world's Top100 have stronger willing to return, and the negative effect of academic ranking decreases with time passing; while scholars with a tenure-track position, a tenure position or a permanent position tend to stay overseas, and the hazard rate of staying increases with age. The older scholars have more intentions to go back China, while gender was not a significant factor influencing academic return at the high end. That is, the talent-attracting programs has partly succeeded in bringing back the academics at the high end.

Association Between Atrial Fibrillation and the Risk of Dementia in the Korean Elderly: A 10-Year Nationwide Cohort Study

  • Nah, Min-Ah;Lee, Kyeong Soo;Hwang, Tae-Yoon
    • Journal of Preventive Medicine and Public Health
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    • v.53 no.1
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    • pp.56-63
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    • 2020
  • Objectives: The objective of this study was to determine the effect of atrial fibrillation (AF) on the risk of dementia in the Korean elderly. Methods: A 10-year retrospective cohort study was conducted using the National Health Insurance Service-Senior Cohort database. We excluded those who were under 65 years of age as of January 2006 (n=46 113), those who were diagnosed with dementia between 2002 and 2005 (n=9086), and those with a history of stroke prior to AF diagnosis (n=8392). We used a Cox proportional hazards model with a time-varying covariate to determine whether AF is associated with the risk of dementia after adjusting for potential confounders. Results: In univariable Cox regression, the hazard ratio (HR) of dementia according to AF status was 1.28 (95% confidence interval [CI], 1.23 to 1.33). After adjusting for potential confounders, AF was found to increase the risk of dementia (HR, 1.12; 95% CI, 1.07 to 1.17), Alzheimer dementia (HR, 1.12; 95% CI, 1.07 to 1.17), and vascular dementia (HR, 1.10; 95% CI, 1.03 to 1.18). In patients diagnosed with AF, the incidence of dementia was lower (HR, 0.50; 95% CI, 0.47 to 0.52) in patients who were treated with oral anticoagulants. Conclusions: Investigating the potential risk factors of dementia in an aged society is important. We found a slightly higher risk of dementia in those with AF than in those without AF, and we therefore concluded that AF is a potential risk factor for dementia.

Risk Factors Associated with Cataract and Macular degeneration by in Korean aged 60 years and over (한국인 60세 이상 노년층의 황반변성과 백내장의 위험요인 -국민건강보험공단 노인코호트 자료를 활용하여-)

  • Pak, Hae-Yong;Lee, Eun-Hee;Pak, Yun-Suk
    • Journal of the Korea Convergence Society
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    • v.8 no.10
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    • pp.273-279
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    • 2017
  • Purpose: This study was conducted to identify factors associated with cataract and age-related macular degeneration in elders. Methods: In total, 341,588 men(44.18%,) and women(61.887%), aged over 60, were recruited from Korean National Health Insurance Service-Senior(2002-2013). We also analysed the factors which determine the prevalence of contract (ICD-10: H25) and age-related macular degeneration(ICD-10: H353) using Cox proportional hazard regression model Results: The subjects who were women, in older age, the group of higher income level, with hypertension, with heart disease, and with diabetes, the prevalence of both contract and age-related macular were increased(p<0.0001). Conclusion: The prevalence of contract and age-related macular degeneration were higher in old age of Korean who has chronic diseases such as hypertension, heart disease, and diabetes. The management of chronic diseases are essentially required in elderly for more healthy eye in aged society.

Prognostic Factors Influencing Survival and Success Rates of Autotransplanted Maxillary Canine (자가이식한 상악 견치의 생존율과 성공률에 영향을 주는 예후 인자 연구)

  • Kim, Dong-Hyun;Hyun, Hong-Keun;Kim, Young-Jae;Jang, Ki-Taeg
    • Journal of the korean academy of Pediatric Dentistry
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    • v.44 no.3
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    • pp.317-326
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    • 2017
  • The aim of this study was to investigate the survival and success rates of autotransplanted maxillary canine at the artificially formed recipient socket and evaluate the factors that influence survival and success rates. A total of 28 children who had 37 impacted canines were reviewed over the mean observation time of 25.1 months. Tooth mobility, pathologic root resorption, vertical bone loss, periapical lesion and anklyosis of donor tooth were investigated clinically and radiographically. The survival rate was 100%. The success rate was 64.9%, because 13 teeth were evaluated as unsuccessful. Significant parameter in determining the success rate of autotransplantation was enlarged follicle size of donor tooth according to Cox proportional hazard regression model. The results provide information necessary for clinician to make a better treatment decision about autotransplantation at the artificially formed recipient socket.

Application of Cox and Parametric Survival Models to Assess Social Determinants of Health Affecting Three-Year Survival of Breast Cancer Patients

  • Mohseny, Maryam;Amanpour, Farzaneh;Mosavi-Jarrahi, Alireza;Jafari, Hossein;Moradi-Joo, Mohammad;Monfared, Esmat Davoudi
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.sup3
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    • pp.311-316
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    • 2016
  • Breast cancer is one of the most common causes of cancer mortality in Iran. Social determinants of health are among the key factors affecting the pathogenesis of diseases. This cross-sectional study aimed to determine the social determinants of breast cancer survival time with parametric and semi-parametric regression models. It was conducted on male and female patients diagnosed with breast cancer presenting to the Cancer Research Center of Shohada-E-Tajrish Hospital from 2006 to 2010. The Cox proportional hazard model and parametric models including the Weibull, log normal and log-logistic models were applied to determine the social determinants of survival time of breast cancer patients. The Akaike information criterion (AIC) was used to assess the best fit. Statistical analysis was performed with STATA (version 11) software. This study was performed on 797 breast cancer patients, aged 25-93 years with a mean age of 54.7 (${\pm}11.9$) years. In both semi-parametric and parametric models, the three-year survival was related to level of education and municipal district of residence (P<0.05). The AIC suggested that log normal distribution was the best fit for the three-year survival time of breast cancer patients. Social determinants of health such as level of education and municipal district of residence affect the survival of breast cancer cases. Future studies must focus on the effect of childhood social class on the survival times of cancers, which have hitherto only been paid limited attention.

Association between D-Dimer Levels and the Prognosis of Terminal Cancer Patients in the Last Hours of Life

  • Lee, Hwan Hee;Hwang, In Cheol;Shin, Jinyoung
    • Journal of Hospice and Palliative Care
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    • v.23 no.1
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    • pp.11-16
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    • 2020
  • Purpose: D-dimer levels are known to be associated with poor outcomes in patients with various cancers, but their significance at the end of life remains unclear. This study investigated D-dimer levels as a prognostic indicator for terminal cancer patients in the last hours of life. Methods: The retrospective study was conducted at a palliative care unit of a tertiary cancer center, using a database to analyze the records of patients treated from January 1, 2010 to December 31, 2018. In total, 67 terminal cancer patients with available data on D-dimer levels were included. Patients' demographic data, clinical information, and laboratory values, including D-dimer levels, were collected. Survival was analyzed using the Kaplan-Meier method and the log-rank test. A Cox proportional-hazards model was used to identify prognostic factors of poor survival. Results: The most common site of cancer was the lung (32.8%) and the median survival time was 5 days. Most laboratory results, particularly D-dimer levels, deviated from the normal range. Patients with high D-dimer levels had a significantly shorter survival time than those with low D-dimer levels (4 days vs. 7 days; P=0.012). In the Cox regression analysis, only a high D-dimer level was identified as a predictor of a poor prognosis (hazard ratio, 1.83; 95% confidence interval, 1.09~3.07). Conclusion: Our results suggest that at the very end of life, D-dimer levels may serve as a prognostic factor for survival in cancer patients.

Impact of beta blockers on survival outcomes in ovarian cancer: a nationwide population-based cohort study

  • Baek, Min-Hyun;Kim, Dae-Yeon;Kim, Seon Ok;Kim, Ye-Jee;Park, Young-Han
    • Journal of Gynecologic Oncology
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    • v.29 no.6
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    • pp.82.1-82.13
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    • 2018
  • Objective: The impact of beta blockers (BBs) on survival outcomes in ovarian cancer was investigated. Methods: By using Korean National Health Insurance Service Data, Cox proportional hazards regression was performed to analyze hazard ratios (HRs) with 95% confidence intervals (CIs) adjusting for confounding factors. Results: Among 866 eligible patients, 206 (23.8%) were BB users and 660 (76.2%) were non-users. Among the 206 BB users, 151 (73.3%) were non-selective beta blocker (NSBB) users and 105 (51.0%) were selective beta blocker (SBB) users. BB use in patients aged ${\geq}60$ years, longer duration use (${\geq}1$ year), in patients with Charlson Comorbidity Index (CCI) ${\geq}3$, and in cardiovascular disease including hypertension was associated with better survival outcome. These findings were observed in both NSBB and SBB. When duration of medication was analyzed based on number of days, NSBB (${\geq}180$ days) was associated with improved overall survival (OS) with a relatively shorter period of use compared to SBB (${\geq}720$ days). In multivariate Cox proportional hazards model, longer duration of BB medication (${\geq}1$ year) was an independent favorable prognostic factor for both OS and disease-specific survival in ovarian cancer patients. Conclusion: In our nationwide population-based cohort study, BB use was associated with better survival outcomes in ovarian cancer in cases of long term duration of use, in older patients, and in cardiovascular and/or other underlying disease (CCI ${\geq}3$).

Expression Profiles of Loneliness-associated Genes for Survival Prediction in Cancer Patients

  • You, Liang-Fu;Yeh, Jia-Rong;Su, Mu-Chun
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.1
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    • pp.185-190
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    • 2014
  • Influence of loneliness on human survival has been established epidemiologically, but genomic research remains undeveloped. We identified 34 loneliness-associated genes which were statistically significant for high-lonely and low-lonely individuals. With the univariate Cox proportional hazards regression model, we obtained corresponding regression coefficients for loneliness-associated genes fo individual cancer patients. Furthermore, risk scores could be generated with the combination of gene expression level multiplied by corresponding regression coefficients of loneliness-associated genes. We verified that high-risk score cancer patients had shorter mean survival time than their low-risk score counterparts. Then we validated the loneliness-associated gene signature in three independent brain cancer cohorts with Kaplan-Meier survival curves (n=77, 85 and 191), significantly separable by log-rank test with hazard ratios (HR) >1 and p-values <0.0001 (HR=2.94, 3.82, and 1.78). Moreover, we validated the loneliness-associated gene signature in bone cancer (HR=5.10, p-value=4.69e-3), lung cancer (HR=2.86, p-value=4.71e-5), ovarian cancer (HR=1.97, p-value=3.11e-5), and leukemia (HR=2.06, p-value=1.79e-4) cohorts. The last lymphoma cohort proved to have an HR=3.50, p-value=1.15e-7. Loneliness-associated genes had good survival prediction for cancer patients, especially bone cancer patients. Our study provided the first indication that expression of loneliness-associated genes are related to survival time of cancer patients.

Prognostic Role of PTEN Gene Expression in Breast Cancer Patients from North-East Iran

  • Golmohammadi, Rahim;Rakhshani, Mohammad Hassan;Moslem, Ali Reza;Pejhan, Akbar
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.9
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    • pp.4527-4531
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    • 2016
  • Background: PTEN protein is one of the most important tumour suppressor factors which is detectable by immunohistochemistry. The goal of the present study was to investigate the prognostic role of PTEN gene expression in breast cancer patients. Materials and Methods: This descriptive-analytical study was conducted on 100 breast cancer patients referred to Sabzevar hospitals in the north-east of Iran between 2010 and 2011, who were followed up to 2015. PTEN gene expression in tissue samples was determined using specific monoclonal antibodies and data were analyzed using Chi-square test and Fisher's exact test. Patient survival was analyzed after 4 years of follow-up using the Cox regression model. Results: PTEN gene expression was evident in 70 of 100 cnacer samples but was found at high levels in all non-cancer samples. There was an inverse significant relationship between PTEN gene expression and tumour stage or tumour grade (p<0.001). The expression of PTEN in invasive ductal tumours was lower than in non-invasive tumours. There was also an inverse significant relationship between the hazard of death and PTEN gene expression (p<0.001). In addition, there was an inverse significant relationship between tumour stage and hazard of death (p<0.001). Conclusion: These findings indicate that lack of PTEN gene expression can be a sign of a worse prognosis and poor survival in breast cancer cases.