All Questions
Tagged with cox-model regression
213 questions
0
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1
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What are the differences between PS-match and adjusted Cox regression?
This is more like an extension of the following question: Propensity Score Matching with Cox Regression
I am wondering what are the differences between these:
matching patients with PS and running ...
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0
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18
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How to plot hazard ratio from coxph model with tt() term [closed]
This question is related to another that I posted here:
How to visually assess tt() suitability in coxph
If we have a time-varying HR that arises from a time-dependent coefficient because we have ...
- 857
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0
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31
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How to visually assess tt() suitability in coxph? [closed]
For this example, I am taking cues from the time-dependent survival vignette.
I am interested in understanding how to assess the suitability of a covariate-time interaction using ...
- 857
0
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1
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86
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Dealing with categorical variables on cox regression
I am trying to fit a Cox regression model to my time-to event data and have a categorical variable with 5 different levels. If I don't leave one of the levels out, then I will have multicollinearity, ...
- 57
1
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1
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123
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Discrete-time hazard model vs. conditional logistic regression vs. logistic regression
I was wondering what is the difference between these three models (discrete time cox proportional hazard, conditional logistic regression and logistic regression). I would appreciate it, if you could ...
- 107
0
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1
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209
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Lifelines-CoxTimeVaryingFitter for Multistate Survival Analysis
I am new to survival analysis and cox regression, and have limited statistical background. I have time-to event data for a multistate survival model and I want to fit a cox model for each transition ...
- 57
5
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3
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226
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Cox model - unsure of time unit of analysis
I am running a survival analysis (Cox model) on time to event in cancer patients. The start of followup is end of treatment. Tests for the event (recurrence) are performed every 6 months from cancer ...
- 923
14
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4
answers
969
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Cubic splines in Cox model
I have a question about the cubic splines used in the Cox model to test the linearity for the continuous variables. I read that usually the knots chosen are the quantiles. Can you find different ...
- 209
1
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44
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Count data with time-varying covariates
One way to model count data is to simply count up the number of events as the outcome with an offset of observation time if this varies between people. I presume it's also possible to model count data ...
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46
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Constructing nomogram from approximate model in Regression Modelling Strategies
In section 19.5 in Regression Modelling Strategies by Frank Harrell we make an approximate model using linear regression with ols. Since this is an ols object we have to calculate survival quantities ...
- 101
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118
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Reporting of Cox model w/ restr. cubic splines
I'm new in fitting multivariable Cox models w/ restricted cubic splines.
This is my code:
...
- 33
1
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1
answer
32
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Y axis of calibration plot: incidence per X vs percentage at risk
I am considering showing how mis-calibrated a cox proportional hazard model is by plotting the 10th percentiles of risk on the x axis vs the incidence per 100,000. For each bin in x I could plot data ...
- 219
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2
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187
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Why are linear and spline term estimates so different?
I am working on modelling in an epidemiological setting. I want to estimate the association between an exposure (air pollution) and two event outcomes. To achieve that, I am using a Cox PH model with ...
- 794
1
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2
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62
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Interpretation dummy variables Cox PH model
I'm curious about interpreting the coefficients of dummy variables within a Cox Proportional Hazards (PH) model. Consider a scenario where I have a sample comprising both male and female patients, and ...
- 363
1
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1
answer
65
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Cox Regression: handling a time interval of drug administration when only given once
I would like to investigate the effect of a drug on survival with Cox regression. The drug can be administered either once or twice. In the univariate Cox regression, I see that a shorter time ...
1
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1
answer
1k
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violation of cox proportional hazard assumption
I'm using cox regression to analyse my data. The explanatory variable is a congenital disease (X) and the outcome is an another disease (Y), which is a comorbidity of the congenital disease. I'm ...
- 333
1
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1
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315
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In SAS what is the difference of including treatment variable in model and using the strata statement for treatment variable?
Im building a Cox Regression in SAS. My code looks like this:
...
- 77
1
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1
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28
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Cox-model with exploratory variable measured after start study
I'm working with an unusual dataset, where some of the covariates/characteristics are measured after the start of the study (though without a timestamp!).
Basically, it's a dataset about an auction. ...
- 363
0
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1
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71
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Trying to understand utility of Cox vs. logistic regression
I am refreshing myself on the different types of regression models and am getting a little stuck between logistic regression and Cox regression/survival analysis. Here's an example: Let's say you are ...
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0
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25
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Survival Analysis where part of population never experiences event [duplicate]
We aim to examine the time it takes for a certain event to happen between two different groups of people in our sample. We are thinking of using survival analysis methods for this purpose.
The thing I ...
- 363
1
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1
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299
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Cox Regression model with time-dependent covariates - violated assumption of proportional hazards (PH)
I am currently performing some Cox regression models. The image attached shows a Schönfeld residual based on one of the cox models with a significant p-value which means that the proportional hazards ...
user389026
2
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0
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226
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How to model an interaction in a propensity-score matched dataset
Suppose I am performing a propensity score matched analysis using the MatchIt package in R, following the example reported here: https://kosukeimai.github.io/...
- 706
1
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1
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519
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Using multiple genes building gene signature and survival analysis
This is the paper which is kind of I'm trying to implement based on my set of genes which i have narrowed down from WGCNA analysis.
Its a both conceptual and R related question[How to do it in R] my ...
- 235
2
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1
answer
615
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Residuals pattern in Cox proportional hazards model
I do a survival regression on some time-to-event data (vehicle breakdowns) with some covariates (essentially the age of the vehicle and some boolean variables for vehicle type). I must admit that I am ...
- 621
1
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1
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948
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Presenting spline terms from a Cox model
In the Survival vignette entitled "Spline terms in a Cox model"
https://cran.r-project.org/web/packages/survival/vignettes/splines.pdf
on page 3 there is this graph:
The plot is showing the ...
- 923
1
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1
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248
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Interaction effects in a Cox model
In regression models, usually a (descriptive) indicator of an interaction effect can be plotted via a plot with x-axis with the potential interaction variable (e.g., gender) and the outcome variable ...
- 133
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1
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104
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Representation of a spline regression - it is better to plot y axis in log scale?
I have a quick (perhaps very naive) question here.
Suppose I have a Cox Regression model in which I have modeled a spline curve on a Predcitor. I want to plot the results of this regression (i.e., ...
- 706
0
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1
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79
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time to first medication switch as time-dependent covariate in Cox model
I need help with setting up my dataset to perform survival analysis with a time-dependent covariate. I read the Therneau et al. paper but I'm still unsure of how to set up the counting process format ...
- 173
1
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1
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144
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Difference between family = gaussian() and family = cox.ph(link='identity') in GAM and family = binomial(link="logit")
I wonder how do u decide if family = gaussian() or family = cox.ph(link='identity') or ...
- 165
2
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1
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445
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Latent Class Analysis - Interpretation and integration with survival analysis?
I am approaching to Latent Class Analysis to identify "classes" of patients based on some variables.
Question 1: diagnostics of the results. I already gone through the discussion on whether ...
- 706
5
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1
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2k
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Time to event = 0 in survival analysis?
In survival analysis, is it appropriate to have a time to event value of zero for a subject(s). For example, the subject experiences the event on the same date as their date of entry. Does this cause ...
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2
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2
answers
2k
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Calculating statistical power for a Cox proportional hazards regression with a continuous predictor variable
I have 322 samples with survival data (71 had events) and wish to calculate the power to detect an association with a linear predictor (no covariates) at $\alpha$=0.05 and hazard ratio=1.561. Been ...
2
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2
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124
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Interpretation of Interaction when the results in one of the two groups is not statistically significant
Here is the question. Suppose we have a drug A, and we have conducted a RCT evaluating the risk of death in patients randomised to receive ...
- 706
2
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1
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119
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Is it possible to generate a scatterplot of relative hazard for participants superimposed on Cox regression line?
I have been using the rms package in R to perform Cox regression on time-to-event data. I have used the ...
0
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1
answer
20
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Coding Survival Time: How to handle if a subject dies before your outcome (heart failure, HF) AND they have a HF event =1? [closed]
I am running a cox-regression model and am struggling with how to define my survival time to event (heart failure) if their time to HF (=1) AFTER they have died? i.e. it is documented they have a case ...
3
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1
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4k
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Cox model vs. Fine-Gray: hazard ratios & predicted cumulative incidence under competing risks
I am unclear about deriving both hazard ratios and a predicted cumulative incidence curves under competing risks. After reading this interesting article:
https://statisticalhorizons.com/for-causal-...
- 923
2
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1
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89
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When developing models for effect estimation, is it advisable to perform internal validation and calibration using resampling methods? #rms
In predictive modelling, it is useful to perform resampling methods to assess performance e.g. validate() and calibrate() in the rms package in R. Is it useful / advisable to perform such methods when ...
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1
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Can we compute predicted cumulative incidence after fitting a Cox model?
After fitting a Cox regression, we can compute the predicted survival curve S(t) e.g.
in R:
survfit(formula, newdata, ...)
where formula is a coxph object.
With the KM estimate, cumulative incidence ...
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1
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1
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124
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In the Cox model, how is modelling the hazard equivalent to modelling time to event?
In the Cox model, the dependant variable is often stated as time to event, e.g.
https://www.statsdirect.com/help/survival_analysis/cox_regression.htm
even though in the regression formula we model the ...
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1
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1
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38
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How to handle count type features in survival regression?
I want to understand how to model 'count' or 'customer behaviour' type features in survival analysis.
For example, assume that Netflix wants to predict time to churn after a customer upgrades to a ...
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0
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1
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38
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Should the variable of interest always be placed in the numerator when creating predictive ratios?
Background:
I do research in medical imaging. In a current study I am analyzing a measured variable from images that may predict prognosis/survival. Studies of potential imaging survival predictors ...
- 101
1
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1
answer
198
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Robust standard errors with splines
I realize that large changes in model results between using robust and non-robust standard errors can suggest a misspecified model.
My case refers to using a Cox regression and I have experimented ...
- 409
0
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1
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466
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Anova with stratified Cox model
I'd like to use anova to investigate which variables are important to my Cox model outcome.
I tried using anova from ...
- 409
0
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0
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956
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Robust standard errors in Cox survival analysis
The final step of running a Cox model I've been working on involves performing log-likelihood ratio tests to check the significance of each predictor to the model. I'd like to do this using ...
- 409
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0
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135
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Overall effect for non-binary categorical variable, Cox
There are many great answers on Cross-Validated explaining that the p-values for cox.zph (or other regression models) in R refer ...
- 409
1
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1
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91
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How to control for a variable in a (Cox) regression, but not include it in a predictive model?
I have been analysing some survival datasets for lung transplant patients for the past several months. I have found some variables that are statistically significant - such as year of transplant and ...
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1
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0
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56
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Different results for PH for dummy encoding versus not in Cox regression
I've been running a Cox regression with a dummy encoded dataset. For certain reasons, I tried doing the same procedure by using factor in ...
- 409
0
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1
answer
1k
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Visualization after restricted cubic splines in Cox
I've used pspline to add restricted cubic splines to certain continuous covariates that violated the PH assumption upon first analysis. I identified these covarites ...
- 409
0
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1
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349
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Cox time-varying coefficient memory allocation issue
I'm trying to add time-varying coefficients using the tt() function with coxph to solve the problem of PH violations in my Cox ...
- 409
1
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1
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383
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Hazard ratio from Royston-Parmar model (flexsurv::flexsurvspline)
I have a covariate with time-varying coefficient with two categories (lets call it T), which I have modeled using the Royston-Parmar model from flexsurv package as following.
...
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