All Questions
Tagged with cox-model regression
213 questions
56
votes
5
answers
56k
views
Prediction in Cox regression
I am doing a multivariate Cox regression, I have my significant independent variables and beta values. The model fits to my data very well.
Now, I would like to use my model and predict the survival ...
- 563
38
votes
1
answer
14k
views
Does Cox Regression have an underlying Poisson distribution?
Our small team was having a discussion and got stuck. Does anyone know whether Cox regression has an underlying Poisson distribution. We had a debate that maybe Cox regression with constant time at ...
- 563
20
votes
3
answers
19k
views
Time dependent coefficients in R - how to do it?
Update: Sorry for another update but I've found some possible solutions with fractional polynomials and the competing risk-package that I need some help with.
The problem
I can't find an easy way to ...
- 5,996
14
votes
4
answers
969
views
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
9
votes
3
answers
17k
views
Computing c-index for an external validation of a Cox PH model with R
First off, I'll state that I'm aware many questions get asked about the c-index. I've searched this site and others, and I haven't found an answer for my situation. I can successfully use ...
- 927
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
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
2
answers
7k
views
Cox model with LASSO
Rob Tibshirani propose to use lasso with Cox
regression for variable selection in his 1997 paper
"The lasso method for variable selection in the Cox
model" published in Statistics In Medicine 16:385.
...
user4254
8
votes
5
answers
3k
views
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
8
votes
2
answers
2k
views
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
7
votes
1
answer
6k
views
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
7
votes
1
answer
4k
views
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
7
votes
1
answer
5k
views
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
7
votes
1
answer
11k
views
How to interpret concordance index in Cox models?
I'm new using the survival package in R. Consider an example provided with the package:
...
- 637
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
5
votes
1
answer
2k
views
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 ...
- 923
5
votes
3
answers
226
views
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
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
5
votes
1
answer
5k
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Using the calibrate function in rms package for Cox model: use 'hare' method or 'KM'?
I'm creating a calibration plot for my breast cancer prognostic Cox model, which doesn't include any fancy transformations, using the calibrate() function in the <...
- 927
5
votes
2
answers
187
views
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
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
5
votes
1
answer
842
views
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 ...
- 356
5
votes
0
answers
4k
views
How to better understand when to use Weibull AFT versus Cox Model for Failure Data
I am struggling to understand when I should consider using a Cox regression model versus using a Weibull AFT model to predict the end of life of mechanical components.
I have tried to apply the Cox ...
- 95
5
votes
0
answers
310
views
Interval Censored Survival Analysis [duplicate]
I am conducting a study on neurological diseased patients. I am looking into possible factors related to time-to-dementia. Costs associated with neurological testing allow us to assess all patients in ...
- 973
4
votes
1
answer
260
views
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
2
answers
5k
views
Intuitive explanation of censored data in a Cox model
I use Cox regression (proportional hazards) to model survival for a cohort of patients. Patients are censored (alive (0), dead (1)).
I was wondering how Cox regression uses censored data intuitively. ...
- 51
4
votes
1
answer
3k
views
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
4
votes
1
answer
2k
views
Cox PH model and regression with log-log link function: is there a connection?
In this post: interpreting estimates of cloglog logistic regression, I read that when interpreting the results of a regression with a log-log link function, the exponent of the estimated coefficient ...
4
votes
1
answer
449
views
Why does regression model theory not use measure-theoretic sigma-field type notation but counting process models do?
I have been studying counting process theory for time to recurrent event processes and am interested in the explicit use of the conditioning set in the model notation;
$$E[dN(t)|\mathcal{F}_{t^{-}}]=\...
- 728
4
votes
1
answer
39
views
Extracting relative risk from survival parameters
Brief background: statins are drugs that lower cholesterol. Trials comparing statins with placebo show that statins lower mortality (in terms of hazard ratio) by almost 20% (hazard ratio 0.8). There ...
- 2,403
4
votes
1
answer
4k
views
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
4
votes
1
answer
2k
views
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 ...
- 183
4
votes
1
answer
206
views
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
4
votes
0
answers
736
views
How are absolute risks estimated by the Cox model? [duplicate]
According to my modest understanding, the Cox model is all about estimating hazard ratios, relative measures of risk. However, it is possible (in R using e.g. the packages ...
- 3,814
3
votes
2
answers
697
views
Could Survival Analysis Tells the Probability of Death of Any Individual in Specific Time?
I am quite new to Survival Analysis and has only practiced with python package scikit-survival by its user guide.
I was actually confused by the output of cox ph ...
- 41
3
votes
1
answer
4k
views
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
3
votes
2
answers
814
views
Does it make sense to include ZIP code as a covariate in regression model?
Background
I have a dataset representing a large group of people that I'm using to specify a Cox proportional hazards model of a binary outcome on some explanatory variables. My outcome variable is a ...
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3
votes
2
answers
186
views
Should I use Cox model?
In a study of crowdfunding, I am investigating the relationship between the reputation of a person seeking funding for a project (a continuous variable) and the proportion of funding target received (...
- 715
3
votes
2
answers
3k
views
Why and how does adding an interaction term affects the confidence interval of a main effect?
I was wondering why, in a regression model including an interaction term, the confidence interval of one of the main effects becomes wider.
Consider this Cox regression, where the variable IR_BMI27 ...
- 305
3
votes
1
answer
4k
views
Converting a Continuous variable to categorical for Cox regression
In a Cox regression model where our variable of interest is continuous (e.g., a lab measurement);
If we want to obtain something other than a unit risk ratio for that variable (e.g., the hazard ratio ...
3
votes
1
answer
2k
views
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
3
votes
2
answers
713
views
Interpreting Cox regression
My regression results are as follows.
Variable B exp(B)
age 0.004575 1.004586
capital 0.2250 1.2524
year -0.1026 0.9024
...
- 31
3
votes
2
answers
3k
views
IPTW in Cox Regression model using the WeightIt package - Question on ATT vs. ATE interpretation
I am currently trying to perform some IPTW adjustment in the context of Cox Regression models.
I was interested in expanding my understanding of the differences between ATE vs. ATT estimation. I've ...
- 706
3
votes
2
answers
3k
views
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 ...
- 706
3
votes
1
answer
653
views
High-variance residuals in event group in CoxPH
I am using R and coxph() to fit a Cox proportional hazard model. When I plot the deviance residuals using
...
- 313
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 ...
3
votes
1
answer
423
views
Is it possible to estimate IPTW in two different subgroups to evaluate interaction? (Subgroup Balancing Propensity Score?)
This questions needs a toy example to be explained. I apologize if the question is not clear.
Suppose we have an observational study in which we want to evalute the association between exposure to ...
- 706
3
votes
1
answer
309
views
Difference between CoxPH and logistic regression; data preparation for each model
I'm working on a research project of which the objective is to predict the customer churn probability in the next month. We have a dataset of monthly records for each customer with variables including ...
- 133
3
votes
1
answer
1k
views
Categorising a continuous variable for Cox proportional hazards analysis using "quartiles by event"
A colleague just told me that he categorises continuous data in survival analysis using "quartiles by event". He essentially uses cut-off points that equally distribute events into four ...
- 55
3
votes
1
answer
691
views
Cox Proportional-Hazards Regression vs. Regression modeling of competing risk using Fine and Gray
30000 patients all have one diagnosis in common, 3000 of them have been exposed to a potential risk factor before the common diagnosis. 1500 patients develop a malignancy after the common diagnosis.
...
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