All Questions
Tagged with cox-model regression
213 questions
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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 ...
- 59.5k
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0
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32
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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 ...
- 10.3k
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0
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19
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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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1
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416
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When having non-proportional hazards, should I use stratified Cox by time or Logrank tests within periods?
My data have non-proportional hazards with clear separation. Should I handle it via stratified Cox regression or using separate Log-rank test within subsets?
I will use R only to illustrate.
I want to ...
CommunityBot
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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 ...
CommunityBot
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2
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749
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If I want to adjust survival analysis for a covariate, like age, should I add it "smth+age" or add an interaction with it "smth*age"?
I have a survival analysis with a categorical predictor called "smth". I want to adjust it for age. I don't have any idea if they can interact or not but I guess they can. Now, about the the ...
CommunityBot
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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, ...
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1
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125
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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 ...
- 102k
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 ...
- 102k
1
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0
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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 ...
- 82.8k
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3
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227
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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 ...
- 102k
14
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4
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972
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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 ...
- 69.5k
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0
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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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1
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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:
...
- 39.6k
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 ...
- 102k
2
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1
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285
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Cox proportional hazard Model $R^2 = 1$, good calibration - but Somers' $D = 0.16$
I have analyzed the survival time of a currency Unit "not being recovered" (for a debt) by fitting a Cox P. regression model.
Apparent $R^2=1$ is high, $D_{xy}=0.16$ . After bootstrap ...
- 59.5k
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5
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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 ...
- 642
5
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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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1
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390
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lifelines.CoxPHFitter - how are the p-values calculated? [duplicate]
I assume that lifelines.CoxPHFitter is using a Likelihood-ratio test (or is it using Wald?) to calculate p-values when testing for significance. But I have to be sure: is there an official source ...
CommunityBot
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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 ...
- 128k
1
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1
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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
5
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1
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842
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Piecewise survival analysis?
I am trying to analyze time-to-event data (time to completion of a task). Looking at the KM curves, there is a distinct behavioral change around 12 months. This makes sense, because at 12 months there ...
CommunityBot
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1
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1
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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 ...
- 102k
3
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2
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3k
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Difference in stratification, interaction and subsetting Cox Survival Regression
I'm struggling to understand the actual differences in these three approaches that came to my mind.
The problem is: I want to analyze the impact of age on mortality in my cohort. However, I want to ...
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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 ...
0
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1
answer
377
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Comparing AUC of a binomial model to Cox for a specific time point
I have a model for 2 year mortality which was derived using binomial regression.
Now I want to create a time-to-event model with Cox and I want to compare the performance to the already available ...
CommunityBot
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1
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1
answer
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:
...
- 5,683
2
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2
answers
547
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How can I visualize fitting survival data to a proportional hazards model with a continuous variable?
I have (censored) survival data that I am fitting with a proportional hazards model with a continuous covariate, X (for my purposes, X ranges from 0 to 1). After fitting the model, I get a ...
CommunityBot
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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. ...
- 64.8k
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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1
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1
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274
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Fitting a survival model to see if there is interaction between gender and age
hi I am new to survival analysis. I am trying to fit a cox regression model with age, sex, type of case(local vs imported cases), and regions(urban vs rural). I tries to fit two model
ModelA
...
- 20.4k
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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
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 ...
- 20.4k
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 ...
CommunityBot
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1
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1k
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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 ...
CommunityBot
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2
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0
answers
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
2
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1
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446
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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 ...
- 102k
4
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1
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2k
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Cox survival data with time-varying continuous variable and time fixed covariate
I am interested in the paper entitled "Generating survival times to simulate Cox proportional hazards models with time-varying covariates " (Stat Med. 2012 Dec 20;31(29):3946-58.),and want to simulate ...
2
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1
answer
617
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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 ...
- 102k
1
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1
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950
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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 ...
- 794
1
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1
answer
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 ...
- 30.7k
0
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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., ...
- 102k
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 ...
- 102k
1
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1
answer
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 ...
- 50.5k
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 ...
- 102k
2
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2
answers
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 ...
- 6,020
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 ...
- 64.8k
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 ...
- 102k
0
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1
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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 ...
- 71
2
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1
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183
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Cox Proportional Hazards : Why not "Cox Proportional Survival"?
Recently, I thought of the following question: We are often taught about a "Cox Proportional Hazards Model" - this is able to model the hazard between different cohorts of patients, assuming ...
