The insignificant effect of the androgen deprivation therapy on the incidence of dementia in a retrospective population-based prostate cancer study using the extension of Cox proportional hazard model with time-dependent survival

2021 ◽  
Vol 79 ◽  
pp. S1744
Author(s):  
S.H. Kim ◽  
J.Y. Joung ◽  
S-H. Kim ◽  
Y.A. Kim ◽  
M.S. Yang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Deprivation Therapy ◽  
Hazard Model ◽  
Population Based ◽  
Time Dependent ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
Prostate Cancer Study

scholarly journals No Increased Risk of Alopecia in Ankylosing Spondylitis Patients: A Population-based Cohort Study in Taiwan

2020 ◽  
Author(s):  
Jason Peijer Hsieh ◽  
Hsi-Kai Tsou ◽  
Yung-Heng Lee ◽  
Yu-Hsun Wang ◽  
James Cheng-Chung Wei
Keyword(s):  
Statistical Significance ◽  
Hazard Model ◽  
Population Based ◽  
Hazard Ratio ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Negative Results ◽  
Cox Proportional Hazard ◽  
Increased Risk

Abstract Background: Investigate the association between AS and alopecia.Methods: Using over 1,000,000 patients’ data from Taiwan Longitudinal Health Insurance Database, we selected the sample with ICD code, diagnosing date, index date, and propensity score matching. We had 3,640 patients with AS and 14,560 non-AS controls. Cox proportional hazard model and Kaplan-Meier analysis were used to present the results.Results: The crude and adjusted hazard ratio of AS for developing alopecia showed no statistical significance in the Cox proportional hazard model [crude hazard ratio (HR) 1.16, 95% CI 0.67-1.99; adjusted HR 1.16, 95% CI 0.67-1.98]. Negative results were found as well in subgroup analysis (Age 20-40: HR 1.03, 95% CI 0.53-2.01; Age≧40: HR 1.49, 95% CI 0.58-3.80; Female: HR 1.17, 95% CI 0.43-3.17; Male: HR 1.15, 95% CI 0.61-2.19). A significant positive correlation was found between atopic dermatitis and alopecia (adjusted HR 8.05, 95% CI 1.11-58.14).Conclusions: No increased risk of alopecia was observed in AS patients

Intrahepatic cholangiocarcinoma: Ambitious operations and outcomes.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 345-345
Author(s):  
Mustafa Raoof ◽  
Sinziana Dumitra ◽  
Philip HG Ituarte ◽  
Laleh Melstrom ◽  
Susanne Warner ◽  
...  
Keyword(s):  
Intrahepatic Cholangiocarcinoma ◽  
Health Planning ◽  
Hazard Model ◽  
Population Based ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
Significant Difference ◽  
Specialized Institutions

345 Background: Data from specialized institutions suggests that resection for large ( > 7cm) and mutifocal intrahepatic cholangiocarcinoma (ICC) is safe and feasible. We aim to study this hypothesis using a population-based dataset. Methods: This is a study of a contemporary cohort from California Cancer Registry database (2004-2011) that was merged with Office of Statewide Health Planning and Development inpatient database. All patients with ICC that underwent resection or ablation were included. Tumors were classified into two groups; intrahepatic, small ( < 7cm) & solitary (ISS) vs. extrahepatic extension, large or multifocal (ELM). Mortality was recorded at 90 days. Overall survival (OS) analysis was performed using the Kaplan-Meier and Cox-proportional hazard model. Results: Of the total 275 patients that met the inclusion criteria, 55% were female, 52% were white and median age was 65 years (IQR 55-72). Majority of patients had > 3 segment resection 59% (Ablation 10%, 1-3 segments 30%). Portal lymphadenectomy was performed in 45% of patients. Vascular Invasion was found in 22% of patients, 14% were bilobar and 20% were node positive. Median follow up was 23 months (IQR 13-40). Number of ISS tumors (139, 50.5%) and ELM tumors (136, 49.5%) was similar. The two groups were comparable in regards to age, sex, race, comorbidities, extent of surgery, portal lymphadenectomy, node positivity. ELM tumors were more likely to have vessel invasion (27% vs. 17%, p = 0.048) and be bilobar (26% vs. 2%, p < 0.001). There was no significant difference in overall complication rate (ISS 34%, ELM 27%, p = 0.19) and mortality rate (both groups < 1%, p = 0.32). A multivariate Cox-proportional hazard model demonstrated that age > 60 years, > 1 comorbidity, high grade tumors, ELM tumors (HR 1.63: 95%CI 1.11-2.40; p = 0.013) and LN positivity (HR 2.30: 95%CI 1.49-3.54; p < 0.001) are independently associated with worse OS. Conclusions: Surgical resection of tumors > 7cm, multifocal lesions involving contiguous extrahepatic organs is safe with acceptable morbidity and mortality. Age > 60 years, grade, comorbidity, ELM tumors and LN positivity are independent predictors of worse OS.

Effects of Collinearity on Cox Proportional Hazard Model with Time Dependent Coefficients: A Simulation Study

2020 ◽  
Author(s):  
B. T. Babalola ◽  
W. B. Yahya
Keyword(s):  
Simulation Study ◽  
Cox Model ◽  
Hazard Model ◽  
Time Dependent ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
Correlation Structures ◽  
Time Dependent Covariates

Background: The Cox proportional hazard model has gained ground in Biostatistics and other related fields. It has been extended to capture different scenarios, part of which are violation of the proportionality of the hazards, presence of time dependent covariates and also time dependent co-efficients. This paper focuses on the behaviour of the Cox Model in relation to time coefficients in the presence of different levels of collinearity. Objectives: The objectives of this study are to examine the effects of collinearity on the estimates of time dependent co-effiecients in Cox proportional hazard model and to compare the estimates of the model for the logarithm and the square functions of time. Materials and methods: The Algorithm based on a binomial model was extended in order to incorporate the different correlation structures required for the study. The scaled Schoenfeld residuals plots revealed the behaviour of the estimated betas at different degrees of collinearity. Results and conclusions are based of outcome of simulation study performed only. Results: The estimated betas were compared to the true betas at the different level of collinearity in graphical pattern. Conclusion: The study shows that collinearity is a huge factor that influences the correctness of the estimates of the regressors within the framework of Cox model.

scholarly journals A Study of Factors Affecting the Length of Hospital Stay of COVID-19 Patients by Cox-Proportional Hazard Model in a South Indian Tertiary Care Hospital

2021 ◽  
Vol 12 ◽  
pp. 215013272110002
Author(s):  
Gayathri Thiruvengadam ◽  
Marappa Lakshmi ◽  
Ravanan Ramanujam
Keyword(s):  
Hospital Stay ◽  
Tertiary Care ◽  
Length Of Hospital Stay ◽  
Hazard Model ◽  
Cox Proportional Hazard Model ◽  
Care Hospital ◽  
Proportional Hazard ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
South Indian

Background: The objective of the study was to identify the factors that alter the length of hospital stay of COVID-19 patients so we have an estimate of the duration of hospitalization of patients. To achieve this, we used a time to event analysis to arrive at factors that could alter the length of hospital stay, aiding in planning additional beds for any future rise in cases. Methods: Information about COVID-19 patients was collected between June and August 2020. The response variable was the time from admission to discharge of patients. Cox proportional hazard model was used to identify the factors that were associated with the length of hospital stay. Results: A total of 730 COVID-19 patients were included, of which 675 (92.5%) recovered and 55 (7.5%) were considered to be right-censored, that is, the patient died or was discharged against medical advice. The median length of hospital stay of COVID-19 patients who were hospitalized was found to be 7 days by the Kaplan Meier curve. The covariates that prolonged the length of hospital stay were found to be abnormalities in oxygen saturation (HR = 0.446, P < .001), neutrophil-lymphocyte ratio (HR = 0.742, P = .003), levels of D-dimer (HR = 0.60, P = .002), lactate dehydrogenase (HR = 0.717, P = .002), and ferritin (HR = 0.763, P = .037). Also, patients who had more than 2 chronic diseases had a significantly longer length of stay (HR = 0.586, P = .008) compared to those with no comorbidities. Conclusion: Factors that are associated with prolonged length of hospital stay of patients need to be considered in planning bed strength on a contingency basis.

scholarly journals SMOKING STATUS AFFECTING SURVIVAL OF ADENOCARCINOMA LUNG CANCER PATIENTS IN KUALA LUMPUR, MALAYSIA

2017 ◽  
Vol 10 (9) ◽  
pp. 312
Author(s):  
Nida Sajid Ali Bangash ◽  
Natasha Hashim ◽  
Nahlah Elkudssiah Ismail
Keyword(s):  
Lung Cancer ◽  
Prognostic Significance ◽  
Hazard Model ◽  
Rank Test ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Kuala Lumpur ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
Survival Difference

  Objective: Adenocarcinoma (AC) of the lung is now the most common histologic type of non-small cell lung cancer (NSCLC) worldwide since the past 20 years. This study was conducted to investigate survival difference among smoker and non-smoker lung AC patients.Methods: A retrospective observational study was conducted for 81 advanced NSCLC adult Malaysian patients in Radiotherapy and Oncology Clinic at Hospital Kuala Lumpur, Malaysia. A total of adult 30 Malaysian smokers and 51 non-smokers with lung AC were included. Ex-smokers were not included in the study. Demographic and clinical data were collected and described. For survival analysis, Kaplan–Meier test and log-rank test were used to calculate overall survival (OS) and analyse the difference in the survival curve. Cox proportional hazard model was used to identify prognostic significance of smoking status.Results: Non-smokers showed a significant association with female gender and Stage IV NSCLC. The median OS was higher for non-smokers (493 days) as compared to smokers (230 days). The Cox proportional hazard model showed higher hazard ratio for smokers.Conclusion: Non-smoking is an independent positive prognostic factor in lung AC.

scholarly journals Introduction of Two-Dose Mumps-Containing Vaccine into Routine Immunization Schedule in Quzhou, China, Using Cox-Proportional Hazard Model

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhiying Yin ◽  
Canjie Zheng ◽  
Quanjun Fang ◽  
Xiaoying Gong ◽  
Guoping Cao ◽  
...  
Keyword(s):  
Hazard Model ◽  
Routine Immunization ◽  
Cox Proportional Hazard Model ◽  
Proportional Hazard ◽  
Immunization Schedule ◽  
Proportional Hazard Model ◽  
Cox Proportional Hazard ◽  
Kaplan Meier ◽  
Routine Immunization Schedule ◽  
Different Doses

Mumps is a vaccine-preventable disease caused by the mumps virus, but the incidence of mumps has increased among the children who were vaccinated with one-dose measles-mumps-rubella (MMR) in recent years. In this study, we analyzed the influence of different doses of mumps-containing vaccine (MuCV) against mumps using Cox-proportional hazard model. We collected 909 mumps cases of children who were born from 2006 to 2010 and vaccinated with different doses of MuCV in Quzhou during 2006-2018, which were all clinically diagnosed. Kaplan-Meier survival methods and Cox-proportional hazard model were used to estimate the hazard probabilities. Kaplan–Meier curves showed that the cumulative hazard of male and female has no difference; lower hazards were detected among those who were vaccinated with two-dose MuCV, born in 2006, and infected after supplementary immunization activities (SIA). Cox-proportional hazard regression suggested that onset after SIA, born in 2006, and vaccinated with two-dose MuCV were protective factors against infection even after adjusting for potential confounding effects. Our study showed that it was necessary to revise the diagnostic criteria of mumps and identify RT-PCR as the standard for mumps diagnosis in China. We suggested that routine immunization schedule should introduce two doses of MMR and prevaccination screening should be performed before booster immunization in vaccinated populations.

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