All Questions
15 questions
0
votes
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
0
votes
1
answer
209
views
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
1
vote
1
answer
32
views
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
1
vote
1
answer
519
views
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
1
vote
1
answer
124
views
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 ...
- 923
0
votes
1
answer
1k
views
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
2
votes
1
answer
224
views
When computing period-specific hazard ratio using Cox, should I add variable:strata or full variable * strata?
Let's asusme I want to calculate separate hazards ratio in two periods, split like below.
...
- 23
1
vote
1
answer
617
views
Cox proportional hazards with multiclass dependent variable
Is it possible to perform a multiclass Cox proportional hazards model?
I'm interested in finding the probability of self cure on consumer loans, or just study how self-curing clients behave so as to ...
- 265
2
votes
1
answer
353
views
Cox regression assessing joint relationship between baseline groups? JAMA example
I'm a new R user trying to better understand the analytical framework behind an important JAMA paper (doi:10.1001/jama.291.2.210) and how it can be coded in R. It's objective was to evaluate if, in ...
- 79
2
votes
1
answer
2k
views
Cox PH - R 'rms' package - Concordance (Train, CV & Test)
Please could someone verify if my methodology for calculating these three versions of concordance are correct when using the rms package? I have really struggled to ...
- 479
2
votes
0
answers
110
views
Check if PH or AFT model should be fit
It is unclear to me when it is appropriate to fit an accelerated failure time (AFT) model rather than a proportional hazard (PH) model.
I've tried googling and it appears as though PH models are ...
- 635
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.
...
- 31
1
vote
1
answer
383
views
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
1k
views
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
0
answers
562
views
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