Displaying 20 results from an estimated 20000 matches similar to: "Fitting a Correlated Hazard Model???"
2011 Aug 21
3
pooled hazard model with aftreg and time-dependent variables
Dear R-users,
I have two samples with individuals that are in more than one of the samples
and individuals that are only in one sample. I have been trying to do a
pooled hazard model, stacking one sample below the other, with aftreg and
time-dependent covariates. The idea behind is to see aggregate effects of
covariates, but need to control for ther effects of same individuals in both
samples
2005 Jun 10
1
Estimate of baseline hazard in survival
Dear All,
I'm having just a little terminology problem, relating the language used in
the Hosmer and Lemeshow text on Applied Survival Analysis to that of the
help that comes with the survival package.
I am trying to back out the values for the baseline hazard, h_o(t_i), for
each event time or observation time.
Now survfit(fit)$surv gives me the value of the survival function,
S(t_i|X_i,B),
2011 Oct 06
1
non-cumulative hazard in Cox model with time-dependent covariates
Dear all,
Is there a way to calculate the non-cumulative hazard (instantaneous
hazard), which is the product of baseline hazard and exp{beta*covariate} ?
I knew in survfit, we can get the estimator of cumulative baseline hazard,
but how can we get the non-cumulative one?
Thank you very much!
Koshihaku
--
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2006 Mar 07
1
breslow estimator for cumulative hazard function
Dear R-users,
I am checking the proportional hazard assumption of a cox model for a
given covariate, let say Z1, after adjusting for other relavent covariates
in the model. To this end, I fitted cox model stratified on the discrete
values of Z1 and try to get beslow estimator for the baseline cumulative
hazard function (H(t)) in each stratum. As far as i know, if the
proportionality assumption
2004 Jul 04
2
smooth non cumulative baseline hazard in Cox model
Hi everyone.
There's been several threads on baseline hazard in Cox model but I think
they were all on cumulative baseline hazard,
for instance
http://tolstoy.newcastle.edu.au/R/help/01a/0464.html
http://tolstoy.newcastle.edu.au/R/help/01a/0436.html
"basehaz" in package survival seems to do a cumulative hazard.
extract from the basehaz function:
sfit <- survfit(fit)
H
2010 Nov 16
1
Re : interpretation of coefficients in survreg AND obtaining the hazard function for an individual given a set of predictors
Thanks for sharing the questions and responses!
Is it possible to appreciate how much the coefficients matter in one
or the other model?
Say, using Biau's example, using coxph, as.factor(grade2 ==
"high")TRUE gives hazard ratio 1.27 (rounded).
As clinician I can grasp this HR as 27% relative increase. I can
relate with other published results.
With survreg the Weibull model gives a
2007 Jan 10
2
SAS and R code hazard ratios
Greetings,
I am new to R and have been comparing CPH survival analysis hazard ratios
between R and SAS PhReg. The binary covariates' HRs are the same, however
the continuous variables, for example age, have quite different HRs
although in the same direction. SAS PhReg produces HRs which are the
change in risk for every one increment change in the independent variable.
How do I
2009 Mar 14
1
obtaining the values for the hazard function in a cox regression
Hello ,
I am hoping for some advice regarding obtaining the values for the
hazard function in a cox regression that I have undertaken. I have a
model in the following form, analysed with the package survival (v.
2.34-1) and a log-log plot obtained using Design (v. 2.1-2).
For two variables, the lines in the survival curves crossed. The
statistician I been obtaining advice from (who does not
2004 Aug 13
1
How to use the whole dataset (including between events) in Cox model (time-varying covariates) ?
Hello,
coxph does not use any information that are in the dataset between event
times (or "death times") , since computation only occurs at event times.
For instance, removing observations when there is no event at that time in
the whole dataset does not change the results:
> set.seed(1)
> data <-
as.data.frame(cbind(start=c(1:5,1:5,1:4),stop=c(2:6,2:6,2:5),status=c(rep(
2007 Dec 18
1
hazard ratio of interaction Cox model
Dear Forum,
I have a question about interaction estimate in the Cox model:
why the hazard ratio of the interaction is not produced in the summary of the model?
(Instead, the estimate of the coefficient is given in the print of the model.)
# Example:
modINT <-cph( Surv(T_BASE, T_FIN,STATUS)~ NYHA + ASINI + RFP + FE_REC + XX_PR*XX_DISF)
print(modINT)
coef se(coef) z
2010 Nov 15
1
Proportional hazard model with weibull baseline hazard
Dear R-users,
I would like to fit a fully parametric proportional hazard model with a
weibull baseline hazard and a logit link function. This is, the hazard
function is: lambda_i (t) = lambda_0 (t) psi (x_i* beta)
where lambda_0 is a weibull distribution and psi a logistic distribution.
Does someone know a package and/or function on R to do this?
Thanks.
--
M.L. Avendaño
[[alternative HTML
2006 Apr 03
2
testing proportional hazard in a Cox model including a time-varying covariate
I am using a syntax like coxph(Surv(start, stop, event) ~ X, data) to estimate the effect of X, which may change at each measurement (every 6 months). Is there anyone who knows a way to test the proportional hazard assumption in that case?
Thank you in advance
Jean-François Boudreau
Sherbrooke University
[[alternative HTML version deleted]]
2001 Dec 21
1
proportional hazard with parametric baseline function: can it be estimated in R
Greetings --
I would like to estimate a proportional hazard model with a weibull or
lognormal baseline. I have looked at both the coxph() and survreg()
functions and neither appear (to me ) to do it. Am I missing something in
the docs or is there another terrific package out there that will do this.
Many Thanks.
Carl Mason
2005 Aug 17
1
GLM/GAM and unobserved heterogeneity
Hello,
I'm interested in correcting for and measuring unobserved
heterogeneity ("missing variables") using R. In particular, I'm
searching for a simple way to measure the amount of unobserved
heterogeneity remaining in a series of increasingly complex models
(adding additional variables to each new model) on the same data.
I have a static database of 400,000 or
2012 Jul 01
1
significant difference between Gompertz hazard parameters?
Hello, all.
I have co-opted a number of functions that can be used to plot the
hazard/survival functions and associated density distribution for a Gompertz
mortality model, given known parameters. The Gompertz hazard model has been
shown to fit relatively well to the human adult lifespan. For example, if I
wanted to plot the hazard (i.e., mortality) functions:
pop1 <- function (t)
{
2009 May 05
3
Cox Proportional Hazard with missing covariate data
Dear friends,
I have used R for some time now and have a tricky question about the coxph-function: To sum it up, I am not sure whether I can use coxph in conjunction with missing covariate data in a model with time-variant covariates. The point is: I know how "old" every piece that I oberserve is, but do not have fully historical information about the corresponding covariates. Maybe you
2010 Nov 13
2
interpretation of coefficients in survreg AND obtaining the hazard function for an individual given a set of predictors
Dear R help list,
I am modeling some survival data with coxph and survreg (dist='weibull') using
package survival. I have 2 problems:
1) I do not understand how to interpret the regression coefficients in the
survreg output and it is not clear, for me, from ?survreg.objects how to.
Here is an example of the codes that points out my problem:
- data is stc1
- the factor is dichotomous
2007 May 17
1
Stratified Cox proportional Hazard Model
Hello everyone,
I am a new user of R. Does anybody know how hazard ratios are extracted
for each factor level in a stratified Cox proportional hazard
regression model? I have a cancer data set where the variable
?differentiation? is a factor with three levels: poor, intermediate and
good. I would like to extract the hazard ratio for each grade level and
relate it to another prognostic factor.
2012 Jul 26
1
how to plot hazard function for coxph model?
Dear all,
I have been trying to plot hazard function in R for survival data, but in
vain.
Can anybody help me out in plotting hazard function in R?
Dr Suman Kumar
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Sent from the R help mailing list archive at Nabble.com.
2006 Aug 09
0
exponential proportional hazard model
Dear R-users,
I am looking for a function designed to handle parametric proportional hazard models with a piecewise constant baseline hazard (i.e. dummies for annual intervals) and time-dependent covariates since I'm especially interested about the effect of those covariates on the baseline hazard.
I tried survreg() but this doesn't seem to work since my data looks like this
id/ start/