cox proportional hazard

  1. D

    What is is the meaning of this p-value ?

    i am trying to perform cox regression on survival data of tumor patients with the covariate "resection status". Patients had either biopsy (=0), partial resection(=1) or total resection of the tumor (=2). I have trouble understanding the following: "total resection" (=2) is the reference value...
  2. R

    Logistic regression vs. cox proportional hazards model-which model to choose?

    I want to understand which model to choose for my task and advantage/disadvantage of each model. Basically, I am working on longitudinal patients data. I want to build a model to understand the factors associated with patient rehospitalisation within two years from the day they have been...
  3. M

    Cox proportional hazard analysis with non-uniform samples; power analysis

    We have a study involving 10000 patients, 5000 of them treated with drug A and 5000 with drug B. We want to know if drug A is more effective than B. The median time to event (death) after treatment with drug A is 1000 days and for drug B it is 2000 days. There are two sampling scenario: In...
  4. K

    How to do power analysis

    I want to do power analyses prior doing statistical tests on data to assess for the power it would yield. It mostly is survival data. I want to use Cox etc. What will you recommend, how to perform these?
  5. U

    Rewriting integration by summation

    Suppose that n individuals have lifetimes represented by random variables T_1, T_2, \ldots, T_n. Instead of the observed values for each lifetime, we have a time t_i' which we know is either the lifetime or censoring time. Let us define a variable \delta_i=I(T_i=t_i') that equals 1 if...
  6. M

    Recurrent Event Survival Analysis

    Hi there, I'm working on a research on individuals who enter financial distress using the Cox proportional hazards model. In this case the individuals can get in financial distress multiple times within a time-window such that independency assumption is probably not satisfied. I stumbled upon...
  7. J

    External Validation of Cox Model

    I have two data set (training and validation) for building and validating a Cox model. With the training data set I fitted a cox model using stepwise selection method. The significant variables in the model were the only variables included in the validation model. Is this the right...
  8. R

    Cox regression with age as time scale and the proportional hazards assumption

    Hello. I am currently working on a Cox regression in SPSS (Complex Samples). The cox analysis has age as time scale and calendar year as time-dependent variables, while treatment (y/n) is a factor variable. My problem is that I don't know how to confirm the proportional hazards (PH)...
  9. S

    How to calculate Log Hazard Ratio in SAS

    proc phreg data = analysis ; class c diabetes /descending; model days*ind(0) = c diabetes id/ rl ; id= c *diabetes; hazardratio id; run; I am trying to run a simple Cox Regression in SAS. I cant seem to find a way to calculate log-hazard ratio for my variables in the model. The hazard...
  10. D

    COX models and continuous variables

    Hello everyone. I have a simple and basic question about cox model. When I introduce a continuous variable in the model, the hazard ratio assessed for this variable relates the increase (decrease) of the risk after an increase of one unit of the continuous variable. How to extrapolate for more...
  11. M

    Cox PH regression on fixed-interval (1, 2, 5-year) survival

    Dear all, I am co-author on a manuscript on a study which follows a group of patients from a certain diagnosis and studies risk factors for survival. The main author has chosen to analyze fixed-interval survival rates (1, 2 and 5-year survival) and to compare the rates between two groups of...
  12. A

    Cox Proportional hazard model result interpretation

    Could anyone please help me to interpret results from Cox Proportional hazard model result interpretation.:wave: I am using SAS ENTERPRISE Guide and I have the following results: Analysis of Maximum Likelihood Estimates (shown in the image)