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

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Smoking and Colorectal Cancer Risk in the Korean Elderly (노인 인구에서 흡연과 대장암 발생 위험간의 관련성)

  • Kim, Hwa-Jung;Lee, Seung-Mi;Choi, Nam-Kyong;Kim, Seon-Ha;Song, Hong-Ji;Cho, Young-Kyun;Park, Byung-Joo
    • Journal of Preventive Medicine and Public Health
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    • v.39 no.2
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    • pp.123-129
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    • 2006
  • Objectives : The incidence of colorectal cancer increased greatly among the elderly in Korea, but the relationship between smoking and colon cancer remains controversial. Few studies have targeted Asian elderly people. We analyzed the smoking status, the amount smoked, and the smoking duration as risk factors of colorectal cancer to determine their association and causality. Methods: The cohort members (n=14, 103) consisted of 4,694 males and 9,409 females, and they were derived from the Korea Elderly Phamacepidemilogic Cohort (KEPEC), which was a population-based dynamic cohort. They were aged 65 years or more and they lived in Busan Metropolitan City between from 1993-1998; they were beneficiaries of the Korean Medical Insurance Corporation (KMIC). The baseline information was surveyed by a self-administered mailed questionnaire; after 8.7 person-years of mean follow up period, 100 cases of colorectal cancer occurred. The adjusted relative ratio (aRR) of smoking status, the smoking amount and the smoking duration were calculated from the Cox's proportional hazard model with the never-smokers as a reference group and the Cox model controlled for age, gender, precancerous lesions of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI. Results : Compared with the never smokers, the aRRs were 2.03 (95% CI=1.02-4.03) and 1.36 (95% CI=0.80-2.32) for the ex-smokers and current smokers, respectively. Statistical significant trends were not observed for the dose-relationship among the elderly, either for the mean daily amount smoked (p for trend=0.28) or for the total amount (p for trend=0.15). Still, the aRRs were 1.51 (95% CI=0.97-2.34) for the elderly who smoked less than 40 years and 2.35 (95% CI=1.16-4.74) for the elderly who had 40 years or more of smoking (p for trend=0.06). Smokers who started smoking before the age 20 had an increased aRR of 2.15 (95% CI=1.17-3.93) compared to the never smokers. Conclusions : After controlling for age, gender, precancerous lesion of CRC, medication history of NSAIDs & antibiotics, the alcohol drinking status and BMI, smoking increases the risk of colorectal cancer among elderly people. The age when starting smoking is also important.

Predictors of breast-feeding discontinuation in some followed-up hospital-delivered mothers (추적조사된 대구시내 일부 병원분만 산모에서 모유수유중단 예측변수)

  • Lee, Choong-Won;Lee, Moo-Sik;Park, Jong-Won;Lee, Mi-Young;Kang, Mi-Joung;Shin, Dong-Hoon;Lee, Se-Youp
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.4 s.51
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    • pp.845-862
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    • 1995
  • We followed prospectively some hospital-delivered mothers to identify characteristics of those not initiated breast-feeding and predictors of breast-feeding discontinuation in monthly telephone interviews. Recruits were composed of 482 mothers who delivered their babies at one university hospital and one OB/GYN clinic in September to November 1991. Breast-feeding discontinuation was defined as switch to 100% formula lasting more than one week regardless of solid foods. Average age of the study subjects was 27.3 years of age(standard deviation 3.2). Multiple logistic regression analysis indicated native place, occupation, method of delivery and method of feeding considered to be better for maternal health were statistically significant(p<0.1) between initiators and non-initiators of breast feeding. In starting cohort(N=242) of those initiated breast-feeding, that median of breast-feeding discontinuation were 5 months and 25th and 75th percentiles were 3 and 9 months respectively. In Cox's proportional hazard model, mothers with $10\sim13$ years of education were 2.63 times (95% confidence interval, CI $1.50\sim4.60$) more likely to discontinue than those with less than 9 years of education and those with more than 13 years of education were 3.55 time (95% CI $1.99\sim6.33$). Compared with house wife, mothers with part-time jobs were 1.99 times (95% CI $0.86\sim4.57$) more likely to discontinue and those with employed full-time were 1.55 times (95% CI $0.96\sim2.51$). These results suggest that the predictors of initiation and discontinuation of breast-feeding may be different and different target populations should be selected to promote initiation and to prevent discontinuation of breast-feeding according to the period after birth.

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Prediction of Life-expectancy for Patients with Hepatocellular Carcinoma Based on Prognostic Factors (간암 환자에서 예후인자를 통한 생존기간의 예측)

  • Yeom, Chang-Hwan;Shim, Jae-Yong;Lee, Hye-Ree;Hong, Young-Sun
    • Journal of Hospice and Palliative Care
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    • v.1 no.1
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    • pp.30-38
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    • 1998
  • Background : Hepatocellular carcinomoma is the 3rd most common malignancy and the 2nd most common cause of death in Korea. The prediction of life-expectancy in terminal cancer patients is a major problem for patients, families, and physicians. We would like to investigate the prognostic factors of hepatocellular carcinoma, and therefore contribute to the prediction of the survival time of patients with hepatocellular carcinoma. Methods : A total of 91 patients(male 73, female 18) with hepatocellular carcinoma who were admitted to the hospital between January and lune 1995 were entered into the study, and data were collected prospectively on 28 clinical parameters through medical obligation record. We surveyed an obligation and local district office records, and confirmed the surivival of patients till July, 1996. Using Cox-proportional hazard model, give the significant variables related to survival. These determined prognostic factors. Life regressional analysis was used, there were calculated predicted survival day based on combinations of the significant prognostic factors. Results : 1) Out of 91 patients, 73 were male, and 18 were female. The mean age was $56.7{\pm}10.6$ ears. During the study, except for 16 patients who could not follow up, out of 75 patients, the number of deaths was 57(76%) and the number of survivals was 18(24%). 2) Out of the 28 clinical parameters, the prognostic factors related to reduced survival rate were prothrombin time<40%(relative risk:10.8), weight loss(RR:4.4), past history of hypertension (RR:3.2), ascites(RR:2.8), hypocalcemia(RR:2.5)(P<0.001). 3) Out of five factors, the survival day is 1.7 in all of five, $4.2{\sim}10.0$ in four, $10.4{\sim}41.9$ in three, $29.5{\sim}118.1$ in two, $124.0{\sim}296.6$ in one, 724.0 in none. Conclusion : In hepatocellular carcinoma we found that the prognostic factors related to reduce survival rate were prolonged prothrombin time(<40%), weight loss, past history of hypertension, ascites, and hypocalcemia(<8.7mg/dl). The five prognostic factors enabled the prediction of life-expectancy in patients with hepatocellular carcinoma and may assist in managing patients with hepatocellular carcinomal.

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The Prognostic Value of the Charlson's Comorbidity Index in Patients with Prolonged Acute Mechanical Ventilation: A Single Center Experience

  • Song, Seung Eon;Lee, Sang Hee;Jo, Eun-Jung;Eom, Jung Seop;Mok, Jeong Ha;Kim, Mi-Hyun;Kim, Ki Uk;Lee, Min Ki;Lee, Kwangha
    • Tuberculosis and Respiratory Diseases
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    • v.79 no.4
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    • pp.289-294
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    • 2016
  • Background: The aim of our study was to evaluate the prognostic value of Charlson's weighted index of comorbidities (WIC) in patients with prolonged acute mechanical ventilation (PAMV, ventilator care ${\geq}96$ hours). Methods: We retrospectively enrolled 299 Korean PAMV patients who were admitted in a medical intensive care unit (ICU) of a university-affiliated tertiary care hospital between 2008 and 2013. Survivors were defined as patients who survived for 60 days after ICU admission. Results: The patients' mean age was $65.1{\pm}14.1$ years and 70.6% were male. The mean ICU and hospital length of stay was $21.9{\pm}19.7$ and $39.4{\pm}39.1$ days, respectively. In addition, the 60-day mortality rate after ICU admission was 35.5%. The mean WIC was $2.3{\pm}1.8$, with significant differences between nonsurvivors and survivors ($2.7{\pm}2.1$ vs. $2.1{\pm}1.7$, p<0.05). The area under the curve of receiver-operating-characteristics curve for WIC was 0.593 (95% confidence interval [CI], 0.523-0.661; p<0.05). Based on Kaplan-Meier curves of 60-day survival, WIC ${\geq}5$ had statistically lower survival than WIC <5 (logrank test, p<0.05). In a multivariate Cox proportional hazard model, WIC ${\geq}5$ was associated with poor prognosis (hazard ratio, 1.901; 95% CI, 1.140-3.171; p<0.05). The mortality rate of patients with WIC ${\geq}5$ was 54.2%. Conclusion: Our study showed a WIC score ${\geq}5$ might be helpful in predicting 60-day mortality in PAMV patients.

Analysis on Survival and Prognostic Factors for Cancer Patients with Malignancy-associated Hypercalcemia

  • Zhang, Su-Jie;Hu, Yi;Cao, Jing;Qian, Hai-Li;Jiao, Shun-Chang;Liu, Zhe-Feng;Tao, Hai-Tao;Han, Lu
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6715-6719
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    • 2013
  • Objective: To explore the incidence, clinical characteristics, diagnosis and treatment strategies, prognosis of patients with malignancy-associated hypercalcemia (MAH). Methods: The data of 115 patients with MAH who were treated at the Medical Oncology Department of Chinese PLA General Hospital from Jan., 2001 to Dec., 2010 was retrospectively reviewed. Survival analysis was performed using the Kaplan-Meier method and the Cox proportional hazard model with statistic software SPSS 18.0. Results: The patients had blood calcium levels ranging from 2.77 to 4.87 mmol/L. Except for 9 cases who died or were discharged within 5 days after admission, all other patients recovered to normal blood calcium level after treatment with bisphosphonates or intravenous hydration and diuretics; their survival after occurrence of MAH was from 1 day to 4,051 days, and the median survival time was only 50 days. In the log-rank test, the male, renal metastasis, central nervous system symptoms and hypercalcemia occurring over 140 days after cancer diagnosis were predictors of poor survival (P=0.002, P=0.046, P=0.000, P=0.009). In the COX analysis, being male, central nervous system symptoms and hypercalcemia lasting over 140 days after cancer diagnosis were independent prognostic factors for survival time (RR=2.131, P=0.027; RR=3.054, P=0.002; RR=2.403, P=0.001). According to these factors, a score system was established to predict the patient prognosis and adjust the treatment. Conclusion: Cancer patients with MAH have an extremely poor median survival. Some independent factors indicate poor prognosis, including male gender, central nervous system symptoms and hypercalcemia lasting over 140 days after cancer diagnosis. The prognostic score can serve as a reference for MAH prognosis and treatment, worthy of further investigation.

Visceral Pleural Invasion as a Prognostic Factor for Recurrence in Resected IB Non-small Cell Lung Cancer (완전 절제된 IB 비소세포암에서 재발의 예후인자로의 장측늑막 침범)

  • Kim, Seok;Park, Ki-Sung;Kum, Yoon-Seup;Lee, Sub;Bae, Chi-Hoon;Hyun, Dae-Sung
    • Journal of Chest Surgery
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    • v.42 no.5
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    • pp.610-614
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    • 2009
  • Background: Several trials have reported on whether adjuvant chemotherapy for resected stage IB non-small cell lung cancer is needed. The aim of our study was to investigate prognostic factors for recurrence to help identify patients who should receive adjuvant chemotherapy. Material and Method: We reviewed the cases of 48 stage IB non-small cell lung cancer patients between 1997 and 2006. Disease-free survival and overall survival rates were calculated by the Kaplan-Meier method. Univariate analysis was performed with the log rank test and multivariate analysis was done using Cox's proportional hazard model. Result: The median follow-up time was 48 months. The overall survival rate was 55.9%, and the disease-free survival rate was 48.6%. Of 8 variables, two factors, visceral pleural invasion and Iymphovascular invasion, were prognostic factors of disease-free survival (univariate analysis). Visceral pleural invasion was a significant prognostic factor in multivariate analysis, and overall survival in com-pared one or more variable such as visceral pleural invasion or, and lymphovascular invasion with the other variables. Conclusion: Visceral pleural invasion was identified as a poor prognostic factor and it may help select which patients will benefit from adjuvant chemotherapy in addition to more comprehensive follow-up.

Factors affecting the rehabilitation center exit and reentry among homeless persons with mental illness. (정신장애노숙인의 재활시설 퇴소 및 재입소 영향요인에 관한 연구)

  • Min, So-Young;Lee, Byung-Suk
    • Korean Journal of Social Welfare Studies
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    • v.42 no.1
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    • pp.219-242
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    • 2011
  • This study examined the factors associated with exit from and reentry into the rehabilitation center among homeless persons with mental illness. Shelter use of a total of 203 study population was monitored between 2004 and 2008. Cox's proportional hazard model was employed to analyze the factors influencing the rate of the first exit from and the first reentry into the rehabilitation center. Also, competing risk analysis was conducted to examine the factors differently associated with the type of the first exit from the rehabilitation center: a positive exit and a negative exit. This study found that homeless persons with mental illness were less likely to experience the negative exit while their resident registration status not being abolished on the first entry into the rehabilitation center, having more frequent hospitalizations during the rehabilitation center stay, being connected to the family members, having more participations into the basic rehabilitation, mental rehabilitation, and vocational rehabilitation programs during the rehabilitation center stay. Age, the number of hospitalization and of the participations into the mental rehabilitation programs during the rehabilitation center stay were associated with the rate of the first reentry into the rehabilitation center.

Statistical Estimates from Black Non-Hispanic Female Breast Cancer Data

  • Khan, Hafiz Mohammad Rafiqullah;Ibrahimou, Boubakari;Saxena, Anshul;Gabbidon, Kemesha;Abdool-Ghany, Faheema;Ramamoorthy, Venkataraghavan;Ullah, Duff;Stewart, Tiffanie Shauna-Jeanne
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.19
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    • pp.8371-8376
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    • 2014
  • Background: The use of statistical methods has become an imperative tool in breast cancer survival data analysis. The purpose of this study was to develop the best statistical probability model using the Bayesian method to predict future survival times for the black non-Hispanic female breast cancer patients diagnosed during 1973-2009 in the U.S. Materials and Methods: We used a stratified random sample of black non-Hispanic female breast cancer patient data from the Surveillance Epidemiology and End Results (SEER) database. Survival analysis was performed using Kaplan-Meier and Cox proportional regression methods. Four advanced types of statistical models, Exponentiated Exponential (EE), Beta Generalized Exponential (BGE), Exponentiated Weibull (EW), and Beta Inverse Weibull (BIW) were utilized for data analysis. The statistical model building criteria, Akaike Information Criteria (AIC), Bayesian Information Criteria (BIC), and Deviance Information Criteria (DIC) were used to measure the goodness of fit tests. Furthermore, we used the Bayesian approach to obtain the predictive survival inferences from the best-fit data based on the exponentiated Weibull model. Results: We identified the highest number of black non-Hispanic female breast cancer patients in Michigan and the lowest in Hawaii. The mean (SD), of age at diagnosis (years) was 58.3 (14.43). The mean (SD), of survival time (months) for black non-Hispanic females was 66.8 (30.20). Non-Hispanic blacks had a significantly increased risk of death compared to Black Hispanics (Hazard ratio: 1.96, 95%CI: 1.51-2.54). Compared to other statistical probability models, we found that the exponentiated Weibull model better fits for the survival times. By making use of the Bayesian method predictive inferences for future survival times were obtained. Conclusions: These findings will be of great significance in determining appropriate treatment plans and health-care cost allocation. Furthermore, the same approach should contribute to build future predictive models for any health related diseases.

Cigarette Smoking and Mortality in the Korean Multi-center Cancer Cohort (KMCC) Study (한국인의 흡연과 사망 위험에 관한 코호트 연구)

  • Lee, Eun-Ha;Park, Sue-K.;Ko, Kwang-Pil;Cho, In-Seong;Chang, Soung-Hoon;Shin, Hai-Rim;Kang, Dae-Hee;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.2
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    • pp.151-158
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    • 2010
  • Objectives: The aim of this study was to evaluate the association between cigarette smoking and total mortality, cancer mortality and other disease mortalities in Korean adults. Methods: A total of 14 161 subjects of the Korean Multi-center Cancer Cohort who were over 40 years of age and who were cancer-free at baseline enrollment reported their lifestyle factors, including the smoking status. The median follow-up time was 6.6 years. During the follow-up period from 1993 to 2005, we identified 1159 cases of mortality, including 260 cancer mortality cases with a total of 91 987 person-years, by the national death certificate. Cox proportional hazard regression model was used to estimate the hazard ratio (HR) of cigarette smoking for total mortality, cancer mortality and disease-specific mortality, as adjusted for age, gender, the geographic area and year of enrollment, the alcohol consumption status, the education level and the body mass index (BMI). Results: Cigarette smoking was significantly associated with an increased risk of total mortality, all-cancer mortality and lung cancer mortality (p-trend, < 0.01, <0.01, <0.01, respectively). Compared to non-smoking, current smokers were at a higher risk for mortality [HR (95% CI)=1.3 (1.1 - 1.5) for total mortality; HR (95% CI)=1.6 (1.1 -2.2) for all-cancer mortality; HR (95% CI)=3.9 (1.9-7.7) for lung cancer mortality]. Conclusions: This study's results suggest that cigarette smoking might be associated with total mortality, all-cancer mortality and especially lung cancer mortality among Korean adults.

Association between Participation in a Rehabilitation Program and 1-Year Survival in Patients Requiring Prolonged Mechanical Ventilation

  • Wanho Yoo;Myung Hun Jang;Sang Hun Kim;Soohan Kim;Eun-Jung Jo;Jung Seop Eom;Jeongha Mok;Mi-Hyun Kim;Kwangha Lee
    • Tuberculosis and Respiratory Diseases
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    • v.86 no.2
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    • pp.133-141
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    • 2023
  • Background: The present study evaluated the association between participation in a rehabilitation program during a hospital stay and 1-year survival of patients requiring at least 21 days of mechanical ventilation (prolonged mechanical ventilation [PMV]) with various respiratory diseases as their main diagnoses that led to mechanical ventilation. Methods: Retrospective data of 105 patients (71.4% male, mean age 70.1±11.3 years) who received PMV in the past 5 years were analyzed. Rehabilitation included physiotherapy, physical rehabilitation, and dysphagia treatment program that was individually provided by physiatrists. Results: The main diagnosis leading to mechanical ventilation was pneumonia (n=101, 96.2%) and the 1-year survival rate was 33.3% (n=35). One-year survivors had lower Acute Physiology and Chronic Health Evaluation (APACHE) II score (20.2±5.8 vs. 24.2±7.5, p=0.006) and Sequential Organ Failure Assessment score (6.7±5.6 vs. 8.5±2.7, p=0.001) on the day of intubation than non-survivors. More survivors participated in a rehabilitation program during their hospital stays (88.6% vs. 57.1%, p=0.001). The rehabilitation program was an independent factor for 1-year survival based on the Cox proportional hazard model (hazard ratio, 3.513; 95% confidence interval, 1.785 to 6.930; p<0.001) in patients with APACHE II scores ≤23 (a cutoff value based on Youden's index). Conclusion: Our study showed that participation in a rehabilitation program during hospital stay was associated with an improvement of 1-year survival of PMV patients who had less severe illness on the day of intubation.