[Cox proportional hazards regression][1] is a very popular, semi-parametric method for survival analysis.

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Can you use Cox proportional hazard model for panel data?

I need to regress health variables on pollution (PM10), and I have seen that for variables such as lung cancer that take a long time to develop, papers generally use the Cox proportional hazard model. ...
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Survival model output not consistent with actual data

I am trying to learn Survival modelling using a dummy data. The code is as follows ...
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Comparing between group HR for different age strata

I was asked by a colleague if i knew how to test if between group (cases and controls) HR were higher in one age strata than in another. The design: Matched cohorts of cases (with info on debut age) ...
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Applying Cox Proportional Hazards Model on Discontinuous Variable

I am using coxph in Rstudio to apply Cox Proportional hazards model on my data. This model is easy to use on continuous variable ...
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Difficulties fitting a Cox PH model with categorical interactions to complex survey data

I'm attempting to fit a Cox proportional hazards model to a set of NHANES data; the code to load and clean the data is here, and the resulting dataset is here. The difficulty I'm having is ...
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univariate frailty model in cox ph

Does anyone knows syntax for univariate frailty model for semiparametric (cox ph)? R or stata is okay. I already googling about r package for frailty model, but I thougt all of them used for ...
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the graph of log(-log) for Cox model on survival analysis

I'm studying Cox Regression model on Survival Analysis. While testing validity of Proportional Hazard model, I will use log(-log) graph method in SPSS. First of all, I mention which procedure I'm ...
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Simulating interaction term in Cox model

I am trying to simulate the survival data (by using Weibull distribution) that can fit the Cox model below: h(t) = ho(t). exp(beta1 * X1 + beta2 * X1 * X2) X1 and X2 are binary. I haved tried using ...
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How to derive a simultaneous confidence band for an estimated function?

I'm approximating the functional form of the Cox model by B-splines basis functions. For simplicity, assume there's only one covariate $x$, so my model takes the form \begin{eqnarray*} ...
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Regularized cox survival model with time varying covariates and sparce matrix in R

I was wondering if there is a survival framework in R (or any other language for that matter) for doing the following: Fitting an extended (i.e., time-varying covariates) cox survival model ...
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41 views

Textbook approach to modeling non-proportional hazards in the Cox model

In Cox models with time varying coefficients, the effect of covariates on the hazard is allowed to change through time. In cases where a coefficient has a linear relationship with time, I am aware of ...
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Cox-Snell residuals for Cox model with time varying coefficient

I am using the time transform feature of the coxph function in the survival package to model the effect of a time varying ...
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1answer
17 views

Schoenfeld residual test for model with time varying coefficients?

I'm working with the survival package in R. I fit a Cox proportional hazard model (coxph) and did a scaled Schoenfeld residual test (...
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25 views

Can mediation analysis be done with Cox proportional hazards models?

I am trying to understand what types of open source software projects succeed and stay active for a long time and what types die. I want to use survival analysis because some of the projects in my ...
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1answer
30 views

Kaplan-Meier vs Cox proportional hazards survival estimates

I am conducting a 20 year longitudinal study on firm survival using a number of variable such as size, profitability, cash resource etc. What is the difference between the Kaplan Meier and Cox ...
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27 views

Modelling Length of Hospital Stay, Poisson Regression or Cox Regression Analysis

I would like to find out what people thought about the better or more widely accepted way to model hospital Length of Stay (LOS) is? LOS can be thought of as count data (number of days) with a ...
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1answer
26 views

Possible time-dependent mediation effect in Cox regression

I'm quite new to survival analysis, but would appreciate any advice on how to deal with the following finding in my data analysis/ results interpretation. I have been using R and have used a ...
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16 views

How to plot adjusted Kaplan-Meier Curves?

I am trying to plot adjusted Kaplan-Meier curves. I know publications like to see something graphical. But using R, I don't know how to go about adjusting for something like age, gender, income when ...
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How to use time dependent covariates with cox regression in R

I don't know how to generate time dependent covariates in R for use cox regression. I know you need to reorganize your dataset into intervals between event times. This I believe I can do with the ...
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Observed information matrix in Cox model with constant baseline hazard

I am trying to explore properties of Cox model with (parametric) constant baseline hazard function. So the hazard function for the model is $\lambda(t|Z_i) = \lambda_0(t) ...
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Why doesn't a Cox model with time-dependent co-variates lead to pseudoreplication?

In survival analysis, if we have a time-dependent covariate, it is recommended to split data for each individual into multiple time-periods, with start and end dates for each, such that each time ...
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How to get 95% CI from R's coxph? [migrated]

I have used the following function in R's coxph() to fit a cox hazard model. I want to report the proper statistics; however, there is no 95% CI in the output. ...
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1answer
27 views

Applying Cox's Porportional Hazard model

I have a dataset on two groups. Group 1 (18 subjects) and group 2 (5 subjects). Each subject in the groups had to perform a number of tasks which was timed. The time restriction was 60 seconds. If ...
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42 views

Optimal Cutpoint for Predicted Results from Kaplan Meier and Cox Regression

Is there anyway to get the optimal cutpoint for predicted survival probabilities of the aforementioned survival analysis approaches? Something like the optimal cutpoint from ...
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Can coxph be used for categorical data?

I'm doing some survival analysis and I got the idea to change a binary variable into three-category variable by sub-dividing one category of the binary variable into two new categories. Here's a ...
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62 views

predict from a Cox model with beta coefficients

I fitted a Cox PH model in R with the survival package and the coxph function. I get the beta estimates from this model. How can I use these coefficients to ...
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C-index of a fitted cox model in validation data set

I know that c-index of a cox model can be obtained using survival::survConcordance. Below is an example, ...
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How to get Cox p-value for 20,000 genes?

If you run the following code, you will have a data frame real.dat which has 1063 samples for 20531 genes. There are 2 extra columns named ...
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How to structure data for repeated measures Cox model in R?

I am looking the relationship between a patient's lab values (measured at baseline and post-treatment) and their survival. The lab values are measuring the concentration of the same protein, they are ...
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29 views

Forecasting survival probability using Cox Regression

I'm able to obtain predicted survival probabilities of cox regression using either survfit.coxph or predictSurvProb from ...
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Cox Regression When Event is Uncertain

Hypothetical Situation: I'm trying to create a cox model on data set with some serious quality issues. Sometimes the event goes unreported in our data set. Some patients have a treatment regime that ...
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1answer
43 views

Multivariable survival analysis: adding another variable lowers the p value?

When I was performing the Cox survival analysis on my data, I tried to look at the predictive value of different variables to survival. For example, here I have two variables: 'size' and 'surface'. ...
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48 views

What kind of model should I use for churn risk prediction?

I have a data set containing many client's id, and its behavior characteristics measured each month before churn or censored. Data looks like: id || lifetime period || folow-up time before churn of ...
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Cox PH model with quadratic effect interpretation

I'm fitting a Cox model with non-linear continuous variable with and without a time varying effect (to correct non-PH). My goal is to get risk ratio (hazard ratio) associated with X. I have the Cox PH ...
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1answer
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Validity of PH test using Schoenfeld residuals from Cox model on parametric models

I need to use parametric models to model survival data. If the PH assumption holds, I would fit the data for my two intervention groups using a single covariate for treatment effect. I fit a Cox PH ...
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37 views

Weibull Survival Model with Time Varying Covariates in R

I am trying to run a survival model using the Weibull approach, but the wrinkle is that I have time varying covariates. I am using the survival package in R. My call is: output <- ...
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time varying coefficients in cox proportional hazard model

I am trying to fit a coxph model in R. The study can be described as follows: I have a very large dataset, in counting process form, containing whether or not someone responded to a survey or not. ...
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Machine learning methods which takes time-to-event into account?

My vague understanding is that machine learning methods are based on classification labels. How about a survival type of problem? That is to say, not only "have event" or "have no event", but also ...
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Using results from spline estimation in cox model

Is it possible to incorporate the results from estimating splines into a logistic or proportional hazards model? That is, I'd like to try to use the spline function as a weight for my exposure ...
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What is the reference point for a Cox proprtional hazard spline model?

When trying to fit a Cox model to a continuous term we have a problem interpreting the result. When fitting a linear model the hazard ratio is referenced to the mean of the predictor values, and at ...
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How do you calculate the compared populations in cox hazard ratio problems?

Take a look at the following open-access paper http://www.ncbi.nlm.nih.gov/pubmed/26506242 I've tried doing cox regression in both R and SPSS but I cannot get ...
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Cox regression with penalized package in R

Although I have visited this site several times, this is the first time I make a question, so be kind if it is not in a appropriate form. My problem is part statistical and part R. I am trying to ...
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Computing c-index for an external validation of a Cox PH model with Stata

I have developed a Cox prognostic model based and internally validated it using bootstrapping. I also evaluated its calibration using Harrell’s $c$ statistic and Somers' $D$. I have also checked ...
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Calibration test of cox-model in external validation using stata

I'm planning to validate a cox-risk prediction model in external dataset. As a pert of the validation process, I want to test the calibration of my model in the external dataset. I would appreciate if ...
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Reposted: Calibration and Discrimination of Cox prognostic model with Stata [duplicate]

I'm planning to do an external validation of a Cox-prognostic model against another study and a published risk prediction equation. Yet, my previous exposure is limited validation of logistic model. ...
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Failure to converge after including and interaction between time and a covariate (in survival analysis) in R

I have fit a Cox proportional hazards model to some survival data. I then checked assumption of proportionality of hazards by checking plots of scaled Schoenfeld residuals. based on this, it ...
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41 views

Determine if covariate is confounding in Cox proportional hazards model

I've developed a risk score that predicts patient survival. Now I want to see whether my risk score is independent of cancer stage. I've already determined that there's no interaction between the two, ...
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Cox proportional hazards model: response to reviewer's comment on prognostic significance

I am answering a reviewer's comments on a manuscript (medical). In one analysis I run a univariate Cox regression analysis on the variable "has disease vs hasn't disease" as stated by a clinical ...
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1answer
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Violation of proportional hazard for covariate but not for interaction it's part of in a Cox Proportional Hazards model

I have a problem in which one of the covariates in my model violates the assumption of proportional hazards, but the interaction it is part of does not. Data info: Lifespan - mosquito time to death ...
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KM versus Cox model

This question is in general, but I would also like to know how the answer pertains to building the model in R. I have some time to event data and want to do some ...