• 제목/요약/키워드: Cox regression

검색결과 497건 처리시간 0.031초

한국 성인의 근감소증 위험도 평가점수 모형 개발 (Developing the Sarcopenia Risk Assessment Model in Korean Adults)

  • 배은정;박일수
    • 한국학교ㆍ지역보건교육학회지
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    • 제23권4호
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    • pp.81-93
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    • 2022
  • Objectives: The purpose of this study was to develop a model for comprehensively evaluating the risk of sarcopenia in Korean adults and to generate the sarcopenia risk scorecard model based on the results. Methods: The participants of the study were 7,118 adults without sarcopenia in the first basic survey, and a longitudinal analysis was conducted using data from the 1st to 8th survey (2006-2020) of the Korean Longitudinal Study of Aging (KLoSA). The data were analyzed using Rao-Scott chi-square test and weighted Cox proportional hazards regression of complex sampling design. The sarcopenia risk scorecard model was developed by Cox proportional hazards regression using points to double the odds (PDO) method. Results: The findings show that the risk factors for sarcopenia in Korean adults were gender, age, marital status, socioeconomic status, body mass index (BMI), regular exercise, diabetes and arthritis diagnosis. In the scorecard results, the case of exposure to the highest risk level was 100 points. The highest score range were given in the order of age over 65, low BMI, and low socioeconomic status. Conclusions: The significance of this study is that the causal relationship between various factors and the occurrence of sarcopenia in Korean adults was identified. Also, the model developed in this study is expected to be useful in detecting participants with risk of sarcopenia in the community early and preventing and managing sarcopenia through appropriate health education.

Engineering Valuation Based on Small Samples

  • Cho, Jin-Hyung;Lee, Sae-Jae;Seo, Bo-Chul
    • 산업경영시스템학회지
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    • 제29권1호
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    • pp.143-150
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    • 2006
  • Box-Cox model and T-factor method have been widely used to measure economic depreciations for industrial property. The Box-Cox model which combines economic efficiency with depreciation pattern is here extended to the reliability function. To do so a Rayleigh distribution which has been used to estimate the reliability of current assets was chosen as an efficiency curve of marginal productivity. Such an approach provides the possibility to classify the efficiency curves into four categories. It is also possible to analyze the types of depreciation curves. Therefore, the power family of a non-linear Box-Cox model could be set at certain constant values, then the model can be transformed into a linear model to estimate the economic depreciation rates by utilizing the reliability function. Estimating the resultant linear regression equation requires minimal number of observations, while at the same time facilitating the test of hypothesis on depreciation rates.

Developing a Molecular Prognostic Predictor of a Cancer based on a Small Sample

  • Kim Inyoung;Lee Sunho;Rha Sun Young;Kim Byungsoo
    • 한국통계학회:학술대회논문집
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    • 한국통계학회 2004년도 학술발표논문집
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    • pp.195-198
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    • 2004
  • One Important problem in a cancer microarray study is to identify a set of genes from which a molecular prognostic indicator can be developed. In parallel with this problem is to validate the chosen set of genes. We develop in this note a K-fold cross validation procedure by combining a 'pre-validation' technique and a bootstrap resampling procedure in the Cox regression . The pre-validation technique predicts the microarray predictor of a case without having seen the true class level of the case. It was suggested by Tibshirani and Efron (2002) to avoid the possible over-fitting in the regression in which a microarray based predictor is employed. The bootstrap resampling procedure for the Cox regression was proposed by Sauerbrei and Schumacher (1992) as a means of overcoming the instability of a stepwise selection procedure. We apply this K-fold cross validation to the microarray data of 92 gastric cancers of which the experiment was conducted at Cancer Metastasis Research Center, Yonsei University. We also share some of our experience on the 'false positive' result due to the information leak.

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Mixture of Wild Panax Ginseng and Red-Mold Rice Extracts Activates Macrophages through Protection of Cell Regression and Cytokine Expression in Methotrexate-Treated RAW264.7 Cells

  • Shin, Heung-Mook
    • 대한한의학회지
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    • 제30권6호
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    • pp.69-79
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    • 2009
  • Objective: In this study, the immunomodulatory activity of a mixture of wild Panax ginseng and red-mold rice extracts (MPR) on RAW 264.7 macrophage cells in the presence and absence of methotrexate (MTX), an anti-cancer drug, was investigated. Methods and Results: In the cell viability, MPR showed a significant cell proliferation and inhibited cell regression by red-mold rice (RMR) alone or MTX alone. MPR induced moderate increase in nitric oxide (NO) production. NO production and inducible nitric oxide synthase (iNOS) mRNA expression by LPS decreased after MPR treatment. In addition, MPR slightly induced COX-2 mRNA expression, but it did not affect the expression of COX-2 mRNA by LPS treatment. In RT-PCR analyses, MPR induced IL-$1{\alpha}$, IL-$1{\beta}$, IL-6, and TNF-$\alpha$ mRNA expression, but had no effect on IL-10 and TGF-$\beta$, regardless of MTX treatment. Furthermore, MPR did not interfere with the cytotoxicity of MTX against MCF-7 human breast carcinoma cells. Conclusions: MPR is efficacious in protecting against MTX-induced cell regression as a result of macrophage activation, resulting in induction of cytokine expression, implying that MPR could be considered an adjuvant in MTX-chemotherapy.

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Screening for Patients with Non-small Cell Lung Cancer Who Could Survive Long Term Chemotherapy

  • Wu, Xue-Yan;Huang, Xin-En
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권2호
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    • pp.647-652
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    • 2015
  • Background: Lung cancer was one of the most common cancers in both men and women all over the world. In this study, we aimed to clarify who could survive after long term chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). Methods: We enrolled 186 patients with stage IV NSCLC after long term chemotherapy from Jun 2006 to Nov 2014 diagnosed in Jiangsu Cancer Hospital. Multiple variables like age, gender, smoking, histology of adenocarcinoma and squamous-cell cancer, number of metastatic sites, metastatic sites (e.g. lung, brain, bone, liver and pleura), hemoglobin, lymphocyte rate (LYR), Change of LYR during multiple therapies, hypertension, diabetes, chronic bronchitis, treatments (e.g.radiotherapy and targeted therapy) were selected. For consideration of factors influencing survival and response for patients with advanced NSCLC, logistic regression analysis and Cox regression analysis were used in an attempt to develop a screening module for patients with elevated survival after long term chemotherapy become possible. Results: Of the total of 186 patients enrolled, 69 survived less than 1 year (short-term group), 45 one to two years, and 72 longer than 3 years (long-term group). For logistic regression analysis, the short-term group was taken as control group and the long-term group as the case group. We found that age, histology of adenocarcinoma, metastatic site (e.g. lung and liver), treatments (e.g. targeted therapy and radiotherapy), LYR, a decreasing tendency of LYR and chronic bronchitis were individually associated with overall survival by Cox regression analysis. A multivariable Cox regression model showed that metastatic site (e.g. lung and liver), histology of adenocarcinoma, treatments (e.g. targeted therapy and radiotherapy) and chronic bronchitis were associated with overall survival. Thus metastatic site (e.g. lung and liver) and chronic bronchitis may be important risk factors for patients with advanced NSCLC. Gender, metastatic site (e.g. lung and liver), LYR and the decreasing tendency of LYR were significantly associated with long-term survival in the individual-variable logistic regression model (P<0.05). On multivariate logistic regression analysis, gender, metastatic site (e.g. lung and liver) and the decreasing tendency of LYR associated with long-term survival. Conclusions: In conclusion, female patients with stage IV adenocarcinoma of NSCLC who had decreasing tendency of LYR during the course therapy and had accepted multiple therapies e.g. more than third-line chemotherapy, radiotherapy and/or targeted therapy might be expected to live longer.

산재근로자의 첫 직업복귀기간에 관한 연구 (The Study of the First Return-to-work of Injured Workers)

  • 박은주
    • 한국사회복지학
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    • 제64권4호
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    • pp.359-381
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    • 2012
  • 본 연구는 산재근로자의 첫 직업복귀기간의 추이를 살펴보고, 이에 영향을 미치는 요인을 분석하고자 하였다. 이를 위하여 2009년 요양종결한 산재근로자를 대상으로 설문조사를 실시하여 최종적으로 791명의 자료를 이용하였으며, 카플란-마이어 분석과 콕스 회귀분석을 활용하여 분석하였다. 카플란-마이어 분석결과, 재해이후 첫 직업복귀 추이를 보면 1개월 이내 복귀하는 경우가 2.65%, 6개월 이내 28.82%, 12개월 이내 50.95%, 24개월 이내 71.69%로 나타났으며, 요양종결 이후 첫 직업복귀 추이를 보면 요양중 혹은 종결 직후 복귀하는 경우가 29.46%, 1개월 이내 36.41%, 6개월 이내 56.64%, 12개월 이내 67.54%로 나타났다. 그리고 재해이후 첫 직업복귀기간은 여성보다는 남성이, 연령이 낮을수록, 임금이 높을수록, 요양중 실직하지 않은 경우, 원직복귀한 경우, 허리질환에 비하여 골절이, 수술하지 않은 경우, 요양기간이 짧을수록, 장해가 경할수록, 직업훈련을 받은 경우가 첫 복귀가 빨랐다. 요양종결이후 첫 직업복귀기간은 여성보다는 남성이, 연령이 낮을수록, 원직복귀한 경우, 장해가 경할수록, 직업훈련을 받은 경우가 첫 복귀가 빨랐다. 이러한 연구결과를 바탕으로 하여 연구의 함의 및 정책적 개입 방안들을 제시하였다.

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Prognostic Prediction Based on Dynamic Contrast-Enhanced MRI and Dynamic Susceptibility Contrast-Enhanced MRI Parameters from Non-Enhancing, T2-High-Signal-Intensity Lesions in Patients with Glioblastoma

  • Sang Won Jo;Seung Hong Choi;Eun Jung Lee;Roh-Eul Yoo;Koung Mi Kang;Tae Jin Yun;Ji-Hoon Kim;Chul-Ho Sohn
    • Korean Journal of Radiology
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    • 제22권8호
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    • pp.1369-1378
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    • 2021
  • Objective: Few attempts have been made to investigate the prognostic value of dynamic contrast-enhanced (DCE) MRI or dynamic susceptibility contrast (DSC) MRI of non-enhancing, T2-high-signal-intensity (T2-HSI) lesions of glioblastoma multiforme (GBM) in newly diagnosed patients. This study aimed to investigate the prognostic values of DCE MRI and DSC MRI parameters from non-enhancing, T2-HSI lesions of GBM. Materials and Methods: A total of 76 patients with GBM who underwent preoperative DCE MRI and DSC MRI and standard treatment were retrospectively included. Six months after surgery, the patients were categorized into early progression (n = 15) and non-early progression (n = 61) groups. We extracted and analyzed the permeability and perfusion parameters of both modalities for the non-enhancing, T2-HSI lesions of the tumors. The optimal percentiles of the respective parameters obtained from cumulative histograms were determined using receiver operating characteristic (ROC) curve and univariable Cox regression analyses. The results were compared using multivariable Cox proportional hazards regression analysis of progression-free survival. Results: The 95th percentile value (PV) of Ktrans, mean Ktrans, and median Ve were significant predictors of early progression as identified by the ROC curve analysis (area under the ROC curve [AUC] = 0.704, p = 0.005; AUC = 0.684, p = 0.021; and AUC = 0.670, p = 0.0325, respectively). Univariable Cox regression analysis of the above three parametric values showed that the 95th PV of Ktrans and the mean Ktrans were significant predictors of early progression (hazard ratio [HR] = 1.06, p = 0.009; HR = 1.25, p = 0.017, respectively). Multivariable Cox regression analysis, which also incorporated clinical parameters, revealed that the 95th PV of Ktrans was the sole significant independent predictor of early progression (HR = 1.062, p < 0.009). Conclusion: The 95th PV of Ktrans from the non-enhancing, T2-HSI lesions of GBM is a potential prognostic marker for disease progression.

The Prostaglandin Synthase 2/cyclooxygenase 2 (PTGS2/COX2) rs5277 Polymorphism Does not Influence Risk of Colorectal Cancer in an Iranian Population

  • Khorshidi, Fatemeh;Haghighi, Mahdi Montazer;Mojarad, Ehsan Nazemalhosseini;Azimzadeh, Pedram;Damavand, Behzad;Vahedi, Mohsen;Almasi, Shohreh;Aghdaei, Hamid Asadzadeh;Zali, Mohammad Reza
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권8호
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    • pp.3507-3511
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    • 2014
  • Background: The prostaglandin-endoperoxide synthase 2 [PTGS2, commonly known as cyclooxygenase-2 (COX-2)] is an enzyme induced by proinflammatory stimuli that is often overexpressed in malignant tissue and involved in the synthesis of prostaglandins and thromboxanes, regulators of processes such as inflammation, cell proliferation, and angiogenesis, all relevant for cancer development. We investigated whether a functional genetic polymorphism, rs5277, in COX-2 may have a risk-modifying effect on sporadic colorectal cancer in an Iranian population. Materials and Methods: We conducted a case-control study on 167 patients with colorectal cancer and 197 cancer-free controls in Taleghani Hospital in Tehran, Iran, between 2007 and 2011. Peripheral blood samples of both groups were processed for DNA extraction and genotyping of the COX-2 gene polymorphism (rs5277) using PCR-RFLP. RFLP results were confirmed by direct sequencing. Logistic regression analysis was performed to calculate the adjusted odds ratio (OR) and 95% confidence interval (95% CI). Results: There was no significant difference in the distribution of COX-2 gene rs5277 polymorphism genotype and the allelic form, among CRC patients compared with the healthy control group (p: 0.867). Conclusions: Our results suggest that rs5277 polymorphism in COX2 could not be a good prognostic indicator for patients with CRC.

Cox 비례위험모형을 이용한 변액연금 해지율의 추정 (Estimation of lapse rate of variable annuities by using Cox proportional hazard model)

  • 김유미;이항석
    • Journal of the Korean Data and Information Science Society
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    • 제24권4호
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    • pp.723-736
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    • 2013
  • 해약율의 추정은 최근 보험제도의 변화 (국제회계기준의 도입에 따른 현금흐름방식의 가격산출체계 시행, 무해약환급금 보험상품의 판매 허용 등)에 따라 보험료의 결정과 손익분석 그리고 리스크 관리 등에 있어서 중요한 요소로 부각되고 있다. 특히, 변액연금은 최저보증옵션으로 인하여 보험계약자의 해약요소가 중요시되고 다른 보험 상품에 비해 복잡하므로 차별성 있는 통계모형의 선택과 분석이 필요하다. 기존의 해약률 연구는 실태분석 또는 회귀분석을 위주로 모형화하는 것에 초점이 맞추어져 있었으나 본 연구에서는 변액연금 계약과 관련된 여러 변수와 최저보증옵션을 반영하기 위하여 생존분석기법 중 하나인 Cox 비례위험모형을 이용하여 해지율을 추정하였다. 변액연금 해지율에 영향을 미치는 주요변수로는 납입방법, 보험료, 보험기간 대비 유지기간, 계약자적립금 대비 최소보증금, 계약자연령이 있으며 본 연구에서는 이에 관하여 분석해보았다.

Comparative Study on Statistical Packages Analyzing Survival Model - SAS, SPSS, STATA -

  • Cho, Mi-Soon;Kim, Soon-Kwi
    • Journal of the Korean Data and Information Science Society
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    • 제19권2호
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    • pp.487-496
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    • 2008
  • Recently survival analysis becomes popular in a variety of fields so that a number of statistical packages are developed for analyzing the survival model. In this paper, several types of survival models are introduced and considered briefly. In addition, widely used three packages(SAS, SPSS, and STATA) for survival data are reviewed and their characteristics are investigated.

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