• Title/Summary/Keyword: logistic model

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A Breast Cancer Nomogram for Prediction of Non-Sentinel Node Metastasis - Validation of Fourteen Existing Models

  • Koca, Bulent;Kuru, Bekir;Ozen, Necati;Yoruker, Savas;Bek, Yuksel
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.3
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    • pp.1481-1488
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    • 2014
  • Background: To avoid performing axillary lymph node dissection (ALND) for non-sentinel lymph node (SLN)-negative patients with-SLN positive axilla, nomograms for predicting the status have been developed in many centers. We created a new nomogram predicting non-SLN metastasis in SLN-positive patients with invasive breast cancer and evaluated 14 existing breast cancer models in our patient group. Materials and Methods: Two hundred and thirty seven invasive breast cancer patients with SLN metastases who underwent ALND were included in the study. Based on independent predictive factors for non-SLN metastasis identified by logistic regression analysis, we developed a new nomogram. Receiver operating characteristics (ROC) curves for the models were created and the areas under the curves (AUC) were computed. Results: In a multivariate analysis, tumor size, presence of lymphovascular invasion, extranodal extension of SLN, large size of metastatic SLN, the number of negative SLNs, and multifocality were found to be independent predictive factors for non-SLN metastasis. The AUC was found to be 0.87, and calibration was good for the present Ondokuz Mayis nomogram. Among the 14 validated models, the MSKCC, Stanford, Turkish, MD Anderson, MOU (Masaryk), Ljubljana, and DEU models yielded excellent AUC values of > 0.80. Conclusions: We present a new model to predict the likelihood of non-SLN metastasis. Each clinic should determine and use the most suitable nomogram or should create their own nomograms for the prediction of non- SLN metastasis.

Severity-Adjusted Mortality Rates of Coronary Artery Bypass Graft Surgery Using MedisGroups (MedisGroups를 이용한 관상동맥우회술의 중증도 보정사망률에 관한 연구)

  • Kwon, Young-Dae
    • Quality Improvement in Health Care
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    • v.7 no.2
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    • pp.218-228
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    • 2000
  • Background : Among 'structure', 'process' and 'outcome' approaches, outcome evaluation is considered as the most direct and best approach to assess the quality of health care providers. Risk-adjustment is an essential method to compare outcome across providers. This study has aims to judge performance of hospitals by severity adjusted mortality rates of coronary artery bypass graft (CABG) surgery. Methods : Medical records of 584 patients who got the CABG surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups was used to quantify severity of patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex. For evaluation of hospital performance, we calculated ratio of observed number to expected number of deaths and z score [(observed number of deaths - expected number of deaths)/square root of the variance in the number of deaths], and compared observed mortality rate with confidence interval of adjusted mortality rate for each hospital. Results : The overall in-hospital mortality was 7.0%, ranged from 2.7% to 15.7% by hospital. After severity adjustment the mortality by hospital was from 2.7% to 10.7%. One hospital with poor performance was distinctly divided from others with good performance. Conclusion : In conclusion, severity-adjusted mortality rate of CABG surgery might be applied as an indicator for hospital performance evaluation in Korea. But more pilot studies and improvement of methodologies has to be done to use it as quality indicator.

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Circulating folate levels and colorectal adenoma: a case-control study and a meta-analysis

  • Park, Yeong Mi;Youn, Jiyoung;Cho, Chang Ho;Kim, Sung Hi;Lee, Jung Eun
    • Nutrition Research and Practice
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    • v.11 no.5
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    • pp.419-429
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    • 2017
  • BACKGROUND/OBJECTIVES: The relationship between folate and colorectal neoplasia remains controversial. We examined the association between serum folate concentrations and colorectal adenomas in a case-control study of Korean adults and conducted a meta-analysis. SUBJECTS/METHODS: Our case-control study included 113 pairs of case and control who underwent colonoscopy and provided blood samples. We used multivariable conditional logistic regression models to obtain the odds ratios and 95% confidence interval (CIs). For meta-analysis, we identified the relevant studies by searching the PubMed database up to February 2017, included our case-control study and combined the study-specific relative risks (RRs) using a random-effects model. RESULTS: In this case-control study, we included 58 men and 55 women with colorectal adenomas and sex and fasting status matched the controls. We did not find any significant association between the serum folate levels and colorectal adenomas in either men or women. For meta-analysis, a total of eleven studies were included in our analysis and classified into two groups; polyp clearance group (PC) for the studies that included participants who underwent endoscopies and had their polyps removed at baseline; and no polyp clearance group (NPC) for the studies that included participants whose histories of endoscopies were unknown or who underwent their first endoscopies. Four PC (1,311 cases and 1,672 non-cases) and eight NPC studies (3,501 cases and 11,347 non-cases) were included. The combined RRs (95% CIs) comparing the bottom with the top categories of circulating folate levels were 1.07 (0.97-1.18) for the NPC group but 1.45 (1.16-1.74) for the PC group. CONCLUSIONS: Low circulating folate levels were associated with new adenoma formation.

Relationship between diet quality and sarcopenia in elderly Koreans: 2008-2011 Korea National Health and Nutrition Examination Survey

  • Na, Woori;Kim, Jiyu;Chung, Bong Hee;Jang, Dai-Ja;Sohn, Cheongmin
    • Nutrition Research and Practice
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    • v.14 no.4
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    • pp.352-364
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    • 2020
  • BACKGROUND/OBJECTIVES: Given the increasing proportion of the Korean population that is aged 65 years and older, the present study analyzed the relationship between diet quality and sarcopenia in elderly persons by using data from the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: Data for 3,373 persons aged 65 years and over (men: 1,455, 43.1%) were selected from the 2008-2011 KNHANES. Sarcopenia assessments are based on a formula that divides a subject's appendicular skeletal muscle mass (ASM) by their weight (wt) and multiplies that result by 100 ([ASM/wt] × 100). Sarcopenia is present if the subject's result was less than one standard deviation (SD) below the sex-specific mean for a young reference group. For evaluation of diet quality, data obtained via the 24-hour recall method were used to calculate the Diet Quality Index for Koreans (DQI-K). A general linear model was applied in order to analyze general information and nutritional intake according to sarcopenia status. For analysis of the relationship between diet quality and sarcopenia, a binominal logistic regression analysis was undertaken. RESULTS: The sarcopenia prevalence rate among the study subjects aged 65 years and over was 37.6%. The DQI-K of those without sarcopenia was 3.33 ± 0.04 points, while that of those with sarcopenia was 3.45 ± 0.04 points (P < 0.05). The relationship between diet quality and sarcopenia revealed that subjects aged 75 and older had a poor diet quality, and their odds ratio (OR) of sarcopenia presence was significantly higher (OR: 1.807, 95% confidence interval: 1.003-3.254, P < 0.05). CONCLUSIONS: This study revealed that poor diet quality was related to sarcopenia presence in Koreans aged 75 and older. In order to improve the diet quality of the elderly (aged 75 and older), it is necessary to develop dietary improvement guidelines.

Multi-Agent based Operation System Modeling for Automated Container Terminals (자동화 컨테이너 터미널을 위한 멀티에이전트 기반의 운영시스템 모델링)

  • Kang K W.;Yu S. Y.;Mo S. J.;Yim J. H.
    • Journal of Navigation and Port Research
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    • v.29 no.6 s.102
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    • pp.567-572
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    • 2005
  • Trade between nations has been globalized since establishing the WTO(World Trade Organization). By lowering trading barriers under the WTO's system, trade in goods has been gradually increased It requires global logistic system that transports goods in between nations. To save cost of product, cargo of product is containerized and container ships to carry container cargo is going to be bigger: In the market, there are many vendors to provide artificial intelligent modules to operate container terminal. In order to integrate automated container terminal system easily and successfully, this thesis proposes high-level XML/ JMS( eXtensive Markup Language/Java Message Service) communication model and multi-agent based system architecture to share knowledges, solve problems, and active objectives by cooperating between autonomous and intelligent agents that are developed by 3rd party companies in the market. This thesis analyzed current situation of advanced automated container terminal with case studies on implemented systems and difficulties to develop automated container terminal system, reviewed technologies of intelligent agent, communication and automation that unmaned automated container terminal is required.

VA Design of Personalized e-Learning System for the Driver's License Test in Korea (개인 맞춤형 운전면허 학습시스템 설계)

  • Oh, Yong-Sun
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.1055-1060
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    • 2009
  • In this paper, we design an e-Learning system for the Driver's License Teste studying through the Internet. The proposed system make users to be arrived at the goal for the license in a shorter time by offering learning contents and items according to the item-responses made by the users based on the Item Response Theory. Moreover we design the scheme to give the optimum items and the most necessary content to the user during the learning procedure in the form of concept-based objects. All the items in the problem bank DB maintain their difficulties, discriminations, and guessing parameters as is the case of 3-parameter logistic model. In addition user profile DB stores users' status informations, item responses, and ability parameters. Using these structures and combining agents, we can offer the optimum learning process or dynamic personalized studying structure to the user. We can construct interface agent and content selection and feedback agent with the DB's described above. User can study without any awareness of system operations or personal fitting scheme.

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Method for Designing VMS Messages Based on Drivers' Legibility Performance (운전자 판독능력을 고려한 VMS 메시지 설계 방법론 개발 및 적용)

  • Kim, Seong-Min;O, Cheol;Jang, Myeong-Sun;Kim, Tae-Hyeong
    • Journal of Korean Society of Transportation
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    • v.25 no.3
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    • pp.99-109
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    • 2007
  • Variable message signs (VMS), which are used for providing real-time information on traffic conditions and accident occurrences, are one of the important components of intelligent transportation systems VMS messages need to meet human factor requirements: messages should be readable and understandable while driving. Lab-controlled experiments on VMS messages were conducted to obtain useful data for analyzing drivers' responsive characteristics for VMS messages. Binary logistic regression (BLR) modeling techniques were applied to explore the relationships among drivers' message perceptions, message reading time, and amount of VMS messages. Probabilistic outcomes of the proposed BLR-based perception model could be greatly utilized to design VMS messages considering drivers' legibility performance. The major contribution of this study is to develop invaluable statistical models that can be used in designing VMS messages more effectively from the human factor point of view. The results could be further applied to establish the scheme of VMS message phase and duration.

Role of radiotherapy in local control of non-AIDS associated Kaposi's sarcoma patients in Korea: a single institution experience

  • Chang, Ji Hyun;Kim, Il Han
    • Radiation Oncology Journal
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    • v.30 no.4
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    • pp.153-157
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    • 2012
  • Purpose: There has been no definite consensus on standard treatment, either local or systemic, for the Kaposi's sarcoma (KS). Radiotherapy (RT) can be a good local therapeutic choice especially in non-AIDS associated KS (NAKS) for its indolent behavior. Materials and Methods: Medical records of 17 KS patients treated with RT at the Seoul National University Hospital from February 1998 to January 2012 were retrospectively reviewed. One human immunodeficiency virus (HIV)+ patient with 3 lesions was excluded. The total number of the lesion was 23 among the 16 patients. The median follow-up period was 27.9 months. Correlation between response and variables was analyzed using the logistic regression model. Median age of the patients was 75 years. All the 23 lesions were located at the extremities. Fourteen (61%) of those had pain or local swelling as the initial presentation. Ten patients had possible causes of immunodeficiency and were regarded as iatrogenic, and other 6 were classic KS. Median dose of RT was 36 Gy. Results: No KS-related death was observed. Excluding 2 with short-term follow-up only, complete response and partial response were obtained in 2 (9%) and 19 (73%) lesions, respectively. Of those, 3 lesions underwent local progression. Six had out-of-field recurrence after RT. Symptom improvement was achieved in 13 (93%) of 14 patients. Grade 2 skin toxicities were found in 9 lesions but all got improvement after treatment. When divided into responsive and progressive group, free from progression was not related to any of the possible variables. Conclusion: RT is effective in local control of NAKS resulting great response rate.

Polymorphisms of Integrin, Alpha 6 Contribute to the Development and Neurologic Symptoms of Intracerebral Hemorrhage in Korean Population

  • Park, Hyun-Kyung;Jo, Dae-Jean
    • Journal of Korean Neurosurgical Society
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    • v.50 no.4
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    • pp.293-298
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    • 2011
  • Objective : The extracellular matrix (ECM) and cell adhesion molecules play crucial roles in angiogenesis, apoptosis, thrombosis, and inflammation, and also contribute to the pathogenesis of stroke. Integrin, alpha 6 (ITGA6) is a member of ECM adhesion receptors. We investigated whether two single nucleotide polymorphisms (SNPs) (rs11895564, Ala380Thr; rs2293649, Asp694Asp) of ITGA6 were associated with the development and clinical phenotypes of intracerebral hemorrhage (ICH) and ischemic stroke (IS). Methods : We enrolled 199 stroke (78 ICH and 121 IS) and 291 control subjects. Stroke patients were divided into subgroups according to the scores of the National Institutes of Health Stroke Survey (NIHSS, <6 and ${\geq}6$) and Modified Barthel Index (MBI, <60 and ${\geq}60$). SNPStats, SNPAnalyzer, and Helixtree programs were used to calculate odds ratios, 95% confidence intervals, and p values. Multiple logistic regression models were used to analyze genetic data. Results : A missense SNP rs11895564 was associated with the development of ICH (p=0.026 in codominant2, p=0.013 in recessive, p=0.02 in log-additive models; p=0.041 in allele distributions). The A allele frequency of rs11895564 was higher in the ICH group (13.5%) than in the control group (8.1%). In the clinical phenotypes, rs11895564 and rs2293649 showed significant associations in the MBI scores of IS (p=0.014 in codominant1 model; p=0.02 in allele distributions) and NIHSS scores of ICH (p=0.017 in codominant2, p=0.035 in recessive, p=0.035 in log-additive models), respectively. Conclusion : These results suggest that ITGA6 may be associated with the development and clinical phenotypes of stroke in Korean population.

Effects of Hospital Nurse Staffing on in-hospital Mortality, Pneumonia, Sepsis, and Urinary Tract Infection in Surgical Patients (의료기관 간호사 확보수준이 수술환자의 사망, 폐렴, 패혈증, 요로감염에 미치는 영향)

  • Kim, Yunmi;Cho, Sung-Hyun;June, Kyung Ja;Shin, Soon Ae;Kim, Jiyun
    • Journal of Korean Academy of Nursing
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    • v.42 no.5
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    • pp.719-729
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    • 2012
  • Purpose: This study was done to examine relationships between nurse staffing level and postsurgical patient outcomes using inpatient database from the National Health Insurance. Methods: Records of 111,491 patients who received one of 12 types of surgery between January and December, 2009 were identified and analyzed in this study. Nurse staffing level was measured using adjusted nurse staffing grades from 0 to 7. Patient outcomes were defined as in-hospital mortality, or pneumonia, sepsis, or urinary tract infection after surgery. Logistic regression analyses estimated by Generalized Estimation Model, were used to analyze the association between nurse staffing level and patient outcomes. Results: An inverse relationship was found between nurse staffing and patient mortality. Compared with patients who were cared for in hospitals with the highest nurse staffing (Grades 0-1), increases in the odds of dying were found in those with Grades 6-7 [OR (odds ratio)=2.99, 95% CI (confidence interval)=1.94-4.60], those with Grades 4-5 (OR=1.78, 95% CI=1.24-2.57) and those with Grades 2-3 (OR=1.57, 95% CI=1.25-1.98). Lower nurse staffing level was also associated with higher number of cases in pneumonia and sepsis. Conclusion: Policies for providing adequate nurse staffing is required to enhance quality of care and lead to better perioperative patient outcomes.