Displaying 20 results from an estimated 20000 matches similar to: "sample size for survival curves"
2011 Jun 27
7
cumulative incidence plot vs survival plot
Hi, I am wondering if anyone can explain to me if cumulative incidence (CI) is
just "1 minus kaplan-Meier survival"? Under what circumstance, you should use
cumulative incidence vs KM survival? If the relationship is just CI =
1-survival, then what difference it makes to use one vs. the other?
And in R how I can draw a cumulative incidence plot. I know I can make a
Kaplan-Meier
2017 Nov 01
3
Cox Regression : Spline Coefficient Interpretation?
Hi,
I'm using a Cox-Regression to estimate hazard rates on prepayments.
I'm using the "pspline" function to face non-linearity, but I have no clue
how to interpret the result.
Unfortunately I did not find enough information on the "pspline" function
wether in the survival package nor using google..
I got following output:
* library(survival)*
>
>
>
>
2012 Jul 05
1
Comparing crossing survival curves
Hi
I want to compare the survival curves in two groups. Because the hazards are
not proportional (the curves cross) the log rank test or Cox proportional
hazard test are not suitable. How should such curves be compared? Comands
are welcome....
Thanks in advance
2008 Jan 31
3
Log rank test power calculations
Does anyone have any ideas how I could do a power calculation for a log
rank test. I would like to know what the suggested sample sizes would
be to pick a difference when the control to active are in a ratio of 80%
to 20%.
Thanks
Dan
--
**************************************************************
Daniel Brewer, Ph.D.
Institute of Cancer Research
Email: daniel.brewer at icr.ac.uk
2011 Aug 04
2
survival probability estimate method
Hi, I was reading a paper published in JCO "Prediction of risk of distant recurrence using 21-gene recurrence score in node-negative and node-positive postmenopausal patients with breast cancer treated with anastrozole or tamoxifen: a TransATAC study" (ICO 2010 28: 1829). The author uses a method to estimate the 9-year risk of distant recurrence as a function of continuous recurrence
2006 Apr 07
2
Why is transform="km" the default for cox.zph?
To enhance my understanding, and that of my students, I have a question
about cox.zph in the survival package.
If I have correctly gleaned the high-level point from the 1994
Biometrika paper of Grambsch and Therneau, it looks to me like
cox.zph provides a mechanism to test for a simple trend in plots
of a function of time, g(t) versus the scaled schoenfeld
residuals and it also provides some
2011 Jul 05
3
plotting survival curves (multiple curves on single graph)
Hello.
This is a follow-up to a question I posted last week. With some
previous suggestions from the R-help community, I have been able to
plot survival (, hazard, and density) curves using published data for
Siler hazard parameters from a number of ethnographic populations.
Can the function below be modified, perhaps with a "for" statement, so
that multiple curves (different line
2017 Oct 07
2
Adjusted survival curves
For adjusted survival curves I took the sample code from here:
https://rpubs.com/daspringate/survival
and adapted for my date, but got error.
I would like to understand what is my mistake. Thanks!
#ADAPTATION FOR MY DATA
library(survival)
library(survminer)
df<-read.csv("F:/R/data/base.csv", header = TRUE, sep = ";")
head(df)
ID start stop censor sex age stage treatment
1
2011 Jun 28
1
plotting survival curves with model parameters
Hello.
I am trying to write an R function to plot the survival function (and
associated hazard and density) for a Siler competing hazards model.
This model is similar to the Gompertz-Makeham, with the addition of a
juvenile component that includes two parameters---one that describes
the initial infant mortality rate, and a negative exponential that
describes typical mortality decline over the
2017 Oct 07
2
Adjusted survival curves
For adjusted survival curves I took the sample code from here:
https://rpubs.com/daspringate/survival
and adapted for my date, but ... have a QUESTION.
library(survival)
library(survminer)
df<-read.csv("base.csv", header = TRUE, sep = ";")
head(df)
ID start stop censor sex age stage treatment
1 1 0 66 0 2 1 3 1
2 2 0 18 0 1 2 4 2
3 3 0 43 1 2 3 3 1
4 4 0 47 1 2 3 NA 2
5 5
2004 Nov 02
3
time dependency of Cox regression
Hi,
How can I specify a Cox proportional hazards model
with a covariate which i believe its strength on
survival changes/diminishes with time? The value of
the covariate was only recorded once at the beginning
of the study for each individual (e.g. at the
diagnosis of the disease), so I do not have the time
course data of the covariate for any given individual.
For example, I want to state at the
2011 Jan 14
1
Survfit: why different survival curves but same parameter estimates?
Hello,
I'm trying to estimate a Cox proportional hazard model with time-varying covariates using coxph. The parameter estimates are fine but there is something wrong with the survival curves I get with survfit (results are not plausible).
Let me explain why I think something's wrong.
To make sure I'm setting up my data correctly to estimate a model with time-varying covariates, I
2013 Jan 01
2
Plot survival analysis with time dependent variables
Dear all,
Is there an implementation of Simon & Makuch method of plotting the survival function with time-dependent variables. I?m only able to find event.chart in Hmisc for the purpose and I would prefer the Simon and Makuch method. I believe stata has it implemented for this purpose, but I cannot find it on CRAN.
Simon R, Makuch RW. A non-parametric graphical representation of the
2012 Oct 11
2
Question on survival
Hi,
I'm going crazy trying to plot a quite simple graph.
i need to plot estimated hazard rate from a cox model.
supposing the model i like this:
coxPhMod=coxph(Surv(TIME, EV) ~ AGE+A+B+strata(C) data=data)
with 4 level for C.
how can i obtain a graph with 4 estimated (better smoothed) hazard curve
(base-line hazard + 3 proportional) to highlight the effect of C.
thanks!!
laudan
[[alternative
2011 Nov 20
1
Cox proportional hazards confidence intervals
I am calculating cox propotional hazards models with the coxph
function from the survival package. My data relates to failure of
various types of endovascular interventions. I can successfully
obtain the LR, Wald, and Score test p-values from the coxph.object, as
well as the hazard ratio as follows:
formula.obj = Surv(days, status) ~ type
coxph.model = coxph(formula.obj, df)
fit =
2011 Oct 01
4
Is the output of survfit.coxph survival or baseline survival?
Dear all,
I am confused with the output of survfit.coxph.
Someone said that the survival given by summary(survfit.coxph) is the
baseline survival S_0, but some said that is the survival S=S_0^exp{beta*x}.
Which one is correct?
By the way, if I use "newdata=" in the survfit, does that mean the survival
is estimated by the value of covariates in the new data frame?
Thank you very much!
2007 Oct 01
3
Apparently Conflicting Results with coxph
Dear List:
I have a data frame prepared in the couting process style for including
a binary time-dependent covariate. The first few rows look like this.
PtNo Start End Status Imp
1 1 0 608.0 0 0
2 2 0 513.0 0 0
3 2 513 887.0 0 1
4 3 0 57.0 0 0
5 3 57 604.0 0 1
6 4 0 150.0 1 0
The outcome
2011 Apr 18
1
time dependent hazard ratios
Hi, I am new to time-dependent Cox model to estimate time dependent hazard
ratios. Let me use aml dataset from survival package:
> aml3<-survSplit(aml2,cut=c(5,10,20),end="time",start="start",
event="status",episode="i")
If I want to esimate hazard ratio for each of the time intervals 0-5, 5-10,
10-20 and >=20, would the following calculate
2012 Jan 17
2
net classification improvement?
Greetings,
I have generated several ROC curves and would like to compare the AUCs.
The data are cross sectional and the outcomes are binary. I am testing
which of several models provide the best discrimination. Would it be most
appropriate to report AUC with 95% CI's?
I have been looking in to the "net reclassification improvement" (see
below for reference) but thus far I can only
2007 May 01
7
logrank test
how do l programme the logrank test. l am trying to compare 2 survival curves
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