All Questions
Tagged with cox-model regression
213 questions
9
votes
1
answer
2k
views
Cumulative hazard in the setting of Cox regression of repeated events
Cox regression is commonly extended to estimate repeated events processes (for a quick review see [ 1 ] and [ 2 ]).
In Clark et al's first article in their excellent review series of survival ...
- 252
2
votes
1
answer
3k
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Cox Model vs. Logistic Regression for comparing two treatments? [closed]
I am trying to choose which statistical test(s) to use for my study. It is a retrospective cohort study comparing the outcomes of 2 different surgical oncology techniques (Let's call them Treatment X ...
- 65
1
vote
1
answer
383
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How does time factor into Cox regression or a Cox proportional hazards model?
The hazard function for the Cox proportional hazard model is written as follows.
$$\lambda(t|X_i) = \lambda_0(t)\exp(\beta_1X_{i1} + \cdots + \beta_pX_{ip}) = \lambda_0(t)\exp(X_i \cdot \beta)$$
I ...
- 1,400
2
votes
0
answers
583
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Cox-Snell plot for Cox regression model
Is this Cox-Snell plot of my Cox regression model acceptable?
Or should I keep on looking for a better one?
- 31
2
votes
0
answers
1k
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Predicting Lifetimes using CoxPH
I have a dataset of about 9k rows and 60 features (columns). I have a binary status column (1 - dead, 0 - alive) and a lifetime column in days which is right censored. I am currently using the cox-PH ...
- 121
1
vote
1
answer
6k
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Why are SPSS and R producing different results for a cox regression on the same data, with the same model specification?
I've performed a cox regression in rstudio (version 1.0.136) using the coxph function in the package "OIsurv". I've also performed the same analysis on SPSS using the same dataset, but i keep on ...
- 85
1
vote
0
answers
321
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Different hazard ratios in Cox model, depending on which dummy is omitted?
I'm using a Cox survival analysis model in Stata. My covariates include a series of mutually-exclusive dummies. As in other regression models, I leave one out as a reference.
If I change the ...
- 604
2
votes
1
answer
566
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Defining target variable - Credit Card industry
At the company I work we're trying to define a model to deal with a specific problem, so let me briefly explain how the business works:
1 - Bob has a small Hardware Store, and he buys his stock from ...
- 951
1
vote
0
answers
48
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Survival curve of Cox model
I am investigating factors associated with early discharge (vs full stay) in hospital amongst a cohort. Early discharge is the event. This is not an intervention study. I have 7 factors in the model, ...
- 165
0
votes
1
answer
2k
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How to use survival model to predict when there are time dependent continuous covariates
In my practical projects, I usually track a group of people for a few months, then I run a model based on the first few months behavior. Hopefully I can predict both overall and individual level's ...
- 21
5
votes
1
answer
7k
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Can a Cox Proportional-Hazards Model be built only with continuous predictors
The literature on Survival Analysis is mainly from the Medical science where tipically the researcher want to evaluate the effect of a treatment to that of another one. So far, all the example I read ...
- 349
1
vote
0
answers
562
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Cox regression slope - understanding the sign of the slope
I am using the coxme package in R to perform mixed effect cox regression analysis, and would greatly appreciate some advice on how to interpret the regression ...
- 892
1
vote
1
answer
4k
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Intercept in mixed effects cox regression (coxme in R)
I am using mixed effects Cox models in the R package coxme, with the model
SurvObj ~ Sex*NE + (1|Year)
where Sex is a categorical fixed effect with two levels ...
- 892
2
votes
1
answer
22k
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Difference between Cox regression and logistic regression; question about correlation assessment
What is the difference between Cox regression and a logistic regression? I'm writing my own thesis and I have to choose between these two.
Do I have to assess the covariance between the variables I ...
- 706
2
votes
1
answer
105
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Designing a prognostic model from a randomized controlled trial
I want to develop a prognostic model from outcome data of patients treated in a randomized controlled trial where patients received radiotherapy in one arm and radiotherapy and concurrent chemotherapy ...
- 35
3
votes
1
answer
355
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Can I use Covariate Balancing Propensity Score method to adjust for confounding in a Cox Regression model with splines?
I would like to use the Covariate Balancing Propensity Score (CBPS) method to adjust for confounding because of its optimization properties.
I am doing a Cox regression model on some observed ...
- 31
1
vote
1
answer
2k
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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 ...
- 1,152
1
vote
1
answer
817
views
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 ...
- 101
1
vote
0
answers
53
views
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 ...
- 213
1
vote
2
answers
2k
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Why use ln-ln plot in proportional hazard test?
I recently began studying survival analysis and there is something I am curious about.
Why do we prefer to use the ln-ln survival curve rather than the survival curve in a proportional hazard test? ...
- 11
1
vote
0
answers
240
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Modelling retirement of employees by age where only data of very few years are available
We want to model the retirement of employees. We have data on a yearly base for about 20,000 employees by age and some other properties.
There are two questions:
Suitable Approach
In most cases we ...
- 241
2
votes
1
answer
5k
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Survival Analysis account for repeated measures?
I know from work in mixed effect models and generalized estimation equations that it is important to correct for bias resulting from collecting multiple samples from the same subjects over time.
...
- 181
7
votes
1
answer
5k
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Relative importance of variables in Cox regression
I've understood that relative importance of predictors is a tricky question. Suggested methods range from very complex models to very simple variable transformations. I've understood that the ...
- 2,403
0
votes
1
answer
91
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Can I use Cox Regression here?
I have a data-set where I want to do a regression of survival probability given amount of drug injected into a subject. The more drug injected, the less likely the subject will survive after say, 3 ...
- 7,351
3
votes
1
answer
2k
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Consequences of violating proportional hazards assumption in Cox model
What are the consequences of violating the Proportional Hazards assumption in a Cox Model? I've got a Model where two factors are highly significative, but all the estimated betas associated to the ...
- 157
1
vote
1
answer
391
views
Comparing regression models with different coding of the same linear predictor
How can I determine whether one coding of a linear predictor leads to a better fit of the corresponding regression model than the other?
In the following example, the restricted cubic spline coding of ...
- 575
1
vote
1
answer
2k
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Interpretation Interaction in Cox Regression
I am estimating a discrete choice model with the help of cox regression in SPSS.
I would like to interact two continuous predicting variables.
The main effect of one of the ineracting variables is ...
- 11
1
vote
1
answer
718
views
What are easy steps of finding cutpoint in continuous variable with Time to event outcome, in Stata?
I find it painful to manually guess a dichotomized cutpoint predictor (continuous) for an time to event outcome in Simple Cox proportional hazard model.
Currently I was trying to find the cutpoint ...
7
votes
1
answer
1k
views
Time varying coefficient in Cox model
I have a model for survival after an injury that is borderline passing the Schoenfeld test for the proportional hazards assumption (cox.zph() in R).
However, ...
- 1,333
1
vote
0
answers
117
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How to do Cox regression if we have a variable which violates an assumption?
Is there a better way than stratification to do Cox regression for two variables, one qualitative and other quantitative, the qualitative (and more important one) violates an assumption of Cox ...
- 11
2
votes
1
answer
1k
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Setting up dataset for Cox regression with time-dependent variables
I posed a question about how to set up the code for this question here (Psychometrics: Survival analysis of help seeking behaviors) and @Fomite suggested that I pose a separate question about whether ...
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4
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1
answer
206
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Psychometrics: Survival analysis of help seeking behaviors [closed]
Background:
I'm studying people seeking help. Participants described contacts with between 1 and 3 "responders" (e.g., friends, the police) in order- for example, a participant could have contacted ...
- 658
0
votes
1
answer
929
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Interpreting Cox & Binomial Regression: non-significant Chi-Square values w/ significant wald statistics
Scenario A: In Cox regression, the chi square analysis of the -2 log likelihood (or the omnibus in binomial) is not significant, but some of the values of the Wald statistic corresponding to some of ...
7
votes
1
answer
4k
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Interpretation of coefficients of glmnet - LASSO/Cox model?
I have done a LASSO / Cox model run for a large dataset of 10K observations which has 1200 Variables.
...
- 85
4
votes
1
answer
260
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A peer-reviewer wants more complex statistical modeling - is it reasonable?
I've submitted a manuscript to a journal and the associate editor wrote that his readers will want to know more about how the predictor of main interest (occupation) is related to death, and this will ...
- 2,403
4
votes
1
answer
4k
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Interpreting output of Cox regression model
I am trying to use two variables - activity score (ascore - a whole number indicating amount of activity) and gini (given by Gini-Simpson index - a value ranging between 0 and 1, indicating diversity ...
- 711
2
votes
2
answers
633
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how to deal with dependence/interaction among covariates in a cox regression model
In case of a linear regression, if we are to account for interaction between two regressors x1 and x2, we write a model like
...
- 711
1
vote
1
answer
1k
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Model Selection with Competing risks in Cox regression
When doing cox proportional hazards regression one often has competing risks. The typical approach for this is to fit separate cox proportional hazards models for each risk, censoring the competing ...
- 10.2k
2
votes
1
answer
108
views
R adds unexpected variable to interaction model
Not sure if this is more of a programming question (in which case please move to stack overflow) or a statistical model question (in which case, please read on!)
I'm exploring a data set and doing ...
- 10.2k
9
votes
1
answer
10k
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Violation of Cox Proportional Hazards by a continuous variable
[This question is related to 1 and 2 on this site.]
I fit a Cox model with these three time dependent variables: {s:numeric, C:binary, l:numeric }. I have 1069 ...
- 8,477
8
votes
5
answers
3k
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Determine where hazards starts to increase for a continuous variable
I'm interested in a continuous variable, namely blood pressure.
The higher the blood pressure, the greater the risk of heart attack and stroke.
However, studies frequently report that also low blood ...
- 2,403
4
votes
1
answer
3k
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What does a negative Somers' D say about model discriminative power?
I developed a Cox proportional hazard regression model in R. Then I tried using validate in Professor Harrell's rms package to ...
- 601
7
votes
1
answer
6k
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Difference in chi-squared calculated by anova from cph and coxph
Is there a difference between chi-squared (from coxph -> anova) and Wald chi-squared (from ...
- 575
0
votes
1
answer
487
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Calculating probabilities using cox regression [duplicate]
I have done a multivariate Cox regression in R. The model fits to my data very well.
Now, I would like to use my model and predict the survival probabilities of new observations. I am unclear how to ...
2
votes
1
answer
8k
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How to interpret the output of Cox regression with categorical nominal variables in SPSS?
When I enter a nominal categorical variable as independent variable into the Cox regression procedure, SPSS gives cloaked results. It just reports something like the following:
...
- 1,363
1
vote
3
answers
2k
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Estimating expected lifetime from hazard ratio and estimated base hazard function
Apologies if this is a basic question, I am not very familiar with survival analysis ...
I have trained a gradient boosted Cox proportional hazards model in R, and have been able to obtain reasonable ...
- 21
5
votes
1
answer
655
views
Create age and sexmatched pairs to balance Cox regression further (updated)
I analyze ethnic differences in risk of cardiovascular events (CVD) in a cohort study of patients with coronary heart disease. It is known that immigrants have higher risk of CVD and I intend to show ...
- 2,403
8
votes
2
answers
2k
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Cumulative Hazard Function where "status" is dependent on "time"
This question is in relation to a dataset I've previously discussed here.
I'm trying to determine whether a treatment affects not only the number of visits a patient has to the doctor, but also how ...
- 458
3
votes
2
answers
2k
views
Cox regression with time varying covariates
I am looking for resources on Cox proportional hazards model with time varying covariates. I'm new to survival analysis so I'm looking for something not overly mathematical. I would also appreciate ...
1
vote
0
answers
41
views
Cox regression to see if distribution of disease predicts survival
I'm working with clinical data from a few hundred patients. Every patient was measured at 6 different timepoints with regular intervals.
Each patient is assessed on 3 different domains and given a ...
- 11