All Questions
26 questions
0
votes
0
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14
views
Recurrent event model - time to multiple medication discontinuations
I am using the following recurrent event model (counting process style input) to plot cumulative mean frequency of multiple medication initiations. Just like patients in the study can initiate ...
- 1
0
votes
0
answers
41
views
Marginal structural model using PROC PHREG
I would like to fit a marginal structural model to account for treatment switching during follow-up.
I found a great paper on how to do this in R: https://www.sciencedirect.com/science/article/abs/pii/...
- 635
1
vote
0
answers
392
views
How does the "ZPH" option of PROC PHREG in SAS 9.4 works?
As I saw in SAS 9.4 documentation, the "ZPH" option in PROC PHREG statement requests diagnostics based on the weighted Schoenfeld residuals for checking ...
- 123
11
votes
1
answer
768
views
SAS and R produced different results for the same cox ph model on the same data
I have fitted a Cox ph model using both R 4.3.1 and SAS 9.4 with the same data. In SAS, I used Proc phreg, while coxph function ...
- 123
1
vote
1
answer
315
views
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
vote
1
answer
428
views
Cox model for different time intervals within follow up time
I have a survival data upto 10 years of followup. I now need to run Cox models for different time horizons like 0-2yr, 2yr-4yrs, 4-6yrs and so on. Is there an easy way to do it in SAS or do I need ...
- 33
1
vote
1
answer
136
views
Reformat data problem for Cox model in SAS
I am relatively new to SAS. Currently I am taking survival analysis course, and I am really stuck on reformatting a data into 'counting process' (start, stop) form for fitting a Cox regression model ...
0
votes
1
answer
368
views
How to create KM curves with time-dependent covariate
Some patient received an treatment as treated group and some did not as control group. In order to consider "immortal time bias", I coded the treatment as a time-dependent covariate. Could ...
0
votes
0
answers
2k
views
Interaction with restricted cubic spline - comparison between SAS and R
When performing the same cox-regression in SAS and i R (including and interaction with a 3 knot restricted cubic spline), I receive different parameter estimates (i.e on age_spline 2). In my example ...
- 1
0
votes
0
answers
417
views
How to estimate the n-year Hazard Ratio from PROC PHREG
Dear SAS users in the CV community:
I am using the sample data publicly available at:
https://stats.idre.ucla.edu/wp-content/uploads/2016/02/whas500.sas7bdat
The tutorial is found here along with a ...
- 101
2
votes
2
answers
3k
views
Continuous vs Categorical covariate of interest in Cox Regression
I will use aliases throughout to explain my results in brief and a few questions that have propped up in the process.
Suppose I'm interested in the association of baseline measurement of blood ...
- 367
0
votes
1
answer
1k
views
SAS Proc lifereg phreg and lifetest - survival plot
I have to draw a survival probability plot with three different surviuval estimates using the phreg, lifereg and the lifetest procedure with sas for make a confrontation
the models:
...
- 75
1
vote
1
answer
916
views
Survival analysis - time-dependent covariate with left truncation
I have some data on patients receiving pancreas transplants. Some of these patients have a procedure done post-transplant called enteric conversion, and I am looking at the effect of this conversion ...
- 297
2
votes
0
answers
40
views
Cox-Hazard Ratio differences in Software suits; Manual calculation
Working in clinical research my task is to calculate the Hazard ratio, better to check the calculations of someone else. This first calculation was based on ARM=(3 different treatments) with only t=(...
- 117
1
vote
1
answer
1k
views
Cox Proportional Hazards Model with Time-Dependent Covariate and Late Entries in SAS [closed]
I am trying to fit a model in SAS that allows for both late entries (i.e. left truncation) and a time*covariate interaction. I can fit both separately:
Late entries:
...
- 11
1
vote
0
answers
391
views
Estimated Survival Discrepancies: Kaplan-Meier vs an Extended Cox Regression
I have a massive data set of about 25000 pancreatic cancer patients; extremely quick and depressing mortality rate. I'm interested in survival differences between three groups--no treatment, ...
- 123
1
vote
0
answers
259
views
Poor survival analysis model fit with Gronnesby and Borgan
I have been experiencing issues with model fit. In my example, I have set up a time-varying (counting method) survival analysis model (Cox regression with ...
- 21
0
votes
1
answer
817
views
Proportionality assumption test (SAS) for categorical predictors
For Cox regression with all categorical predictors, I want to model time-dependent covariates (time*cov in Proc PHREG) to ...
- 1
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
2
votes
0
answers
1k
views
Survival Analysis on Telecom Churn in R
I am working on Telecom Churn problem and here is my dataset.
http://www.sgi.com/tech/mlc/db/churn.data
Names - http://www.sgi.com/tech/mlc/db/churn.names
I'm new to survival analysis.Given the ...
- 91
4
votes
2
answers
5k
views
Objective test for proportionality assumption in Cox Regression Model (SAS)?
I was trying to fit Cox Regression (aka Proportional Hazard) model on some cancer data (N=2288). I got the following output from SAS proc phreg:
...
- 601
1
vote
0
answers
125
views
Cox regression problem with time varying covariates
I was working on a cox regression problem and was refering to this link:
http://support.sas.com/documentation/cdl/en/statug/63347/HTML/default/viewer.htm#statug_phreg_sect050.htm
I have few ...
- 31
2
votes
0
answers
167
views
Survival Analysis--All variables failed the proportionality test. What next?
I am building a cox survival analysis model with a retailer's transaction data. Almost all the variables have failed the proportionality test. Can I continue with the Cox model? Should I build a ...
- 21
9
votes
2
answers
2k
views
Large scale Cox regression with R (Big Data)
I am trying to run a Cox regression on a sample 2,000,000 row dataset as follows using only R. This is a direct translation of a PHREG in SAS. The sample is representative of the structure of the ...
- 805
1
vote
1
answer
2k
views
Backward selection in a Cox regression model
My goal is to fit a cox regression model in SAS, for which I use the PROC PHREG statement. As I am still new to regression methods, I would appreciate a little of ...
- 11
6
votes
2
answers
4k
views
How to get convergence using coxph (R) given that model converges using proc phreg (SAS)
I have a data set
...
- 22.4k