similar to: coxph and frailty

Displaying 20 results from an estimated 100 matches similar to: "coxph and frailty"

2008 Nov 24
1
Discrepancy in the PBC data set
The data set in R is wrong. I've found mistakes on 2 lines in a quick look. I don't know if the data is incorrect in the Appendix of Fleming and Harrington as well (someone seems to have borrowed my copy), which is where the data set appears to have been taken from, given all the "-9" codes in it. (Note, Tom Fleming originally got the data from me, so I'm fairly
2006 Sep 03
2
Running cox models
Hi, I'm reading van Belle et al "Biostatistics" and trying to run a cox test using a dataset from: http://faculty.washington.edu/~heagerty/Books/Biostatistics/chapter16.html (Primary Biliary Cirrhosis data link at top of the page), I'm using the following code: --------------- start of code library(survival) liver <-
2011 Apr 20
2
survexp with weights
Hello, I probably have a syntax error in trying to generate an expected survival curve from a weighted cox model, but I can't see it. I used the help sample code to generate a weighted model, with the addition of a "weights=albumin" argument (I only chose albumin because it had no missing values, not because of any real relevance). Below are my code with the resulting error
2008 Nov 21
1
Discrepancy in the regression coefficients for Cox regression - PBC data set
Hi, When I run the following Cox proportional hazards model on the Mayo clinic's PBC data set (given in the "survival" package), the regression coefficients do not agree with the results presented in Table 4.6.3 (p. 195) of Fleming & Harrington's book. library(survival) data(pbc) ans.cox <- coxph(Surv(time, status) ~ log(bili) + log(alb) + age + log(protime) +
2009 Jul 13
0
pbc data
Hi there, Can anyone please help me because I am going to get crazy with the pbc data set. I just want to apply simple cox regression in the data set. I am a beginner in R but I don't think I am doing anything wrong. I have the book of Fleming and Harrington 1990. I perform cox regression by typing: out<- coxph(Surv(times/365,status)~log(bili)+log(proth)+edema+log(albumin)+age) out
2010 Sep 13
0
using survexp and ratetable with coxph object that includes a factor term
Hello, I'm attempting to use the ratetable argument to survexp in the survival package. I use the example from the ?survexp help page below, and then slightly modify it to produce an error. library(survival) data(pbc) #fit a model without any factors pfit1 <- coxph(Surv(time, status > 0) ~ trt + log(bili) + log(protime) + age + platelet, data=pbc) #this works as expected
2008 Mar 02
0
new to latex to pdf
Dear All, I'm trying to teach myself latex along with the latex function in Hmisc and have hit a roadblock that I can't seem to get around. I'd greatly appreciate any pointers. I'm running R 2.6.0 on Windows XP and have Miktex 2.7 installed. I've reproduced the code below, taken from Frank Harrell's latexsummary introduction. My question relates to getting a pdf
2011 Apr 08
1
Variance of random effects: survreg()
I have the following questions about the variance of the random effects in the survreg() function in the survival package: 1) How can I extract the variance of the random effects after fitting a model? For example: set.seed(1007) x <- runif(100) m <- rnorm(10, mean = 1, sd =2) mu <- rep(m, rep(10,10)) test1 <- data.frame(Time = qsurvreg(x, mean = mu, scale= 0.5, distribution =
2009 Jun 23
0
Fractional Polynomials in Competing Risks setting
Dear All, I have analysed time to event data for continuous variables by considering the multivariable fractional polynomial (MFP) model and comparing this to the untransformed and log transformed model to determine which transformation, if any, is best. This was possible as the Cox model was the underlying model. However, I am now at the situation where the assumption that the competing risks
2007 Apr 17
3
Extracting approximate Wald test (Chisq) from coxph(..frailty)
Dear List, How do I extract the approximate Wald test for the frailty (in the following example 17.89 value)? What about the P-values, other Chisq, DF, se(coef) and se2? How can they be extracted? ######################################################> kfitm1 Call: coxph(formula = Surv(time, status) ~ age + sex + disease + frailty(id, dist = "gauss"), data = kidney)
2010 Dec 10
1
survreg vs. aftreg (eha) - the relationship between fitted coefficients?
Dear R-users, I need to use the aftreg function in package 'eha' to estimate failure times for left truncated survival data. Apparently, survreg still cannot fit such models. Both functions should be fitting the accelerated failure time (Weibull) model. However, as G?ran Brostr?m points out in the help file for aftreg, the parameterisation is different giving rise to different
2011 Jul 08
4
Using t tests
Dear Sir, I am doing some work on a population of patients. About half of them are admitted into hospital with albumin levels less than 33. The other half have albumin levels greater than 33, so I stratify them into 2 groups, x and y respectively. I suspect that the average length of stay in hospital for the group of patients (x) with albumin levels less than 33 is greater than those
2005 Mar 17
1
Cross validation, one more time (hopefully the last)
I apologize for posting on this question again, but unfortunately, I don't have and can't get access to MASS for at least three weeks. I have found some code on the web however which implements the prediction error algorithm in cv.glm. http://www.bioconductor.org/workshops/NGFN03/modelsel-exercise.pdf Now I've tried to adapt it to my purposes, but since I'm not deeply familiar
2012 Sep 20
1
Gummy Variable : Doubt
Hi,   I have a system in which I analyze 2 subjects and 1 variable, so I have 2 models as follow:   y ~ x_1[, 1] + x_2[, 1] + x_1[, 2] + x_2[, 2]   Where   x_1[, i] = cos(2 * pi * t / T_i) x_2[, i] = sin(2 * pi * t / T_i)   i = 1, 2   Data have two columns: t and y.   As you can see, I have a multiple components model, with rithm and without trends, and I have a fundamental
2008 Feb 15
12
Transfer Crosstable to Word-Document
# Dear list, # I am an R-beginner and # spent the last days looking for a method to insert tables produced # with R into a word document. I thought about SPPS: copy a table from # an SPO-file and paste it into a word document # (if needed do some formatting with that table). # Annother idea was, to produce a TEX-file, # insert it and make it a word-table. # I found the following libraries, which
2004 Oct 15
1
categorical varibles in coxph
Hello, I wonder when I do coxph in R: coxph( Surv(start, stop, event) ~ x, data=test) If x is a categorical varible (1,2,3,4,5), should I creat four dummy varibles for it? if yes, how can I get the overall p value on x other than for each dummy variable? Thanks Lisa Wang Princess Margaret Hospital Phone 416 946 4501
2002 Oct 08
2
Frailty and coxph
Does someone know the rules by which 'coxph' returns 'frail', the predicted frailty terms? In my test function: ----------------------------------------------- fr <- function(){ #testing(frailty terms in 'survival' require(survival) dat <- data.frame(exit = 1:6, event = rep(1, 6), x = rep(c(0, 1), 3),
2007 Nov 24
1
Hmisc: can not reproduce figure 4 of Statistical Tables and Plots using S and LATEX
Dear R-users: I can not reproduce figure 4 of *Statistical Tables and Plots using S and LATEX* by Prof. Frank Harrell with the following code: rm(list=ls()) library(Hmisc) getHdata(pbc) attach(pbc) age.groups <- cut2(age, c(45,60)) g <- function(y) apply(y, 2, quantile, c(.25,.5,.75)) y <- with(pbc, cbind(Chol=chol,Bili=bili)) # You can give new column names that are not legal S names
2008 Dec 06
0
Inversing a non-monotonic spline
I have developed a GAM model in order to predict Y using 4 X variables. 2 of these X's are factors, and 1 is a spline. Part of the data looks like: Days WRM variety PWM O_EC 31 75 1 90 234 31 79 1 78 283 31 82 1 92 281 31 84 1 96 213 31 99 2 69 247 31 100 2 77 324 31 104 2 74 259 31 118 2 81 282 31 61 3 58 478 31 98 3 83 429 31 98 3 70 379 31 156 3 87 467 31 78 4 56 283 31 97 4 67 282 31
2004 Apr 09
2
Regression models w/ splines
Hi - I am fitting various Cox PH models with spline predictors. After fitting the model, I would like to use termplot() to examine the functional form of the fitted model (e.g., to obtain a plot of the relative risk (or log r.r.) versus the predictors). When there is only 1 predictor in the model, termplot returns a "?". In this case, I have not been able to figure out how to create