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Repeated Measures Survival Analysis per ID and per latency

I have chosen survival analysis and mixed effects to be analyzed in a joint model using the frailty pack. I am not sure if I am dong it right and I need more expert insights. I am testing people's ...
Nadine's user avatar
  • 1
1 vote
0 answers
26 views

Applying one frailty value to all observations in mixed effects cox regression and then recalculating the survival probability

I want to test the difference in survival probabilities for if every observation in my dataset was part of the frailty group with the worst or best frailty value. I want to calculate the survival ...
Luke Jenner's user avatar
0 votes
1 answer
53 views

How is a frailty model in survival analysis expressed

In some sources 1 one reads that the frailty model expands on the cox proportional hazards model $$h_i(t|x_i)=h_0(t)\exp(\beta x_i)$$ by adding a frailty term $z$ like so $$h_i(t|x_i,z_i)=h_0(t)\exp(\...
wanderinganon's user avatar
1 vote
1 answer
932 views

How to interpret the Wald Chi-square test for the frailty term in a mixed-effects Cox survival model?

Background I'm fitting a Cox model to assess the relationship between treatment (binary) and time-to-event (event is also binary) while also controlling for 3 or 4 covariates. Because I want to ...
logjammin's user avatar
  • 729
1 vote
1 answer
179 views

Cox PH controlling for multiple events

I'm working on a cox proportional hazard analysis in R using the survival package. I´m analysing covariate effects on fish movement within a study area. The study area is divided into two zones ("...
Mattias's user avatar
  • 11
0 votes
1 answer
47 views

Survival model for longitudinal data with overlapping exposures

I have a dataset with info on patient exposures (drug 1 / drug 2) and outcomes (hospitalisation / death) over ten years. All patients were prescribed drug 1 on and off over the period (inclusion ...
Joe Schofield's user avatar
3 votes
1 answer
559 views

Correct pooling of shared frailty models fitted on multiply imputed datasets

I'm wondering whether the pool() function from R's mice package correctly pools shared frailty models fitted on multiply imputed ...
schotti's user avatar
  • 521
3 votes
1 answer
215 views

Within-cluster correlation in lognormal shared frailty models

According to Peter Austin (ref. below), in a gamma shared frailty model (i.e. a Cox regression model with cluster specific random effects which are iid logarithms of gamma distributions), the within-...
schotti's user avatar
  • 521
1 vote
1 answer
312 views

Would you choose a joint frailty model or a multi-state model for survival analysis with recurrent events and competing risks?

I am going to analyse data with multiple recurring events and additional terminal event. The recurrent events are of the same kind, no hierarchy in them (like in the Prentice-Williams-Petersen). The ...
MissDoberty's user avatar
1 vote
1 answer
308 views

Which frailty model is better for survival analysis with recurrent events and competing (teminal) risks: joint or shared?

I am going to analyse data with multiple recurring events and additional terminal event. The recurrent events are of the same kind, no hierarchy in them (like in the Prentice-Williams-Petersen). The ...
MissDoberty's user avatar
1 vote
1 answer
686 views

Why do we need Fine-Gray, Andersen-Gill, joint fraily and multiple-state model to model complex survival if basic tools (Cox) can handle it?

The basic methods statistical packages, using K-M or Cox regression, are both to handle both recurrent events and competing risks. This setting is very common in medicine, where we have recurring ...
KartikNashallam44433's user avatar
2 votes
2 answers
740 views

how to estimate multi-state frailty models with comxe and coxph?

I aim at estimating a competing risks / multistate model with frailties with the coxme R-package and the survival package. I ...
teeglaze's user avatar
  • 135
0 votes
1 answer
690 views

How to model competing risks with frailties in R

I am trying to figure out if (a) a competing risks model with frailty-terms is the right method for my data and (b) how to estimate such models in R. My data consists of N ~ 150 individuals with a ...
teeglaze's user avatar
  • 135
1 vote
2 answers
3k views

Cox models in R: cluster, strata, robust, and frailty ... modeling grouped/clustered survival data

Consider a situation where we have individual patient survival data from a series of clinical trials of patients treated in a similar way. We might have a dataset that looks like this, with n total ...
Brant Inman's user avatar
2 votes
0 answers
1k views

Plot survival curves from a Cox proportional hazard model with shared frailties

I am interested in deriving and plotting the survival functions from a Cox proportional hazards model with shared frailties. How can I do this? This question has an answer here, but it is very high ...
Nayef's user avatar
  • 651
0 votes
1 answer
76 views

How to decide if frailty term needed

I´d like to ask the following question: Is there any sound procedure to test event-history/survival data for unobserved heterogeneity or any indicator that shows that a frailty term should be included?...
philipp.kn_98's user avatar
2 votes
1 answer
925 views

Time varying Cox regression, adding in a mixed effect for patient

I've been reading a lot of vignettes and literature on how to approach repeated-measures longitudinal data with time varying components for the purpose of time-to-event or survival analysis. The ...
bandwagoner's user avatar
3 votes
0 answers
619 views

Mixture of two chi-squared distributions

I have a question about something I found in the book Frailty models in survival analysis (Wieneke, 2011). He talks about testing signficance of the frailty term. According to him, Claeskens et al. (...
Cardinal's user avatar
  • 320
0 votes
1 answer
168 views

Question about adding a frailty term in survival() R

If I add a frailty term in the coxph() function using the survival package in R, we model unobserved heterogeneity of clustered data. Does this only model unobserved heterogeneity of overlapping ...
Cardinal's user avatar
  • 320
0 votes
0 answers
158 views

What is the difference between standard errors using the inverse of hessian and calculated using the the inverse of hessian and Fisher information?

In one of R packages for advanced survival analysis, the frailtypack, the output contains standard errors calculated in two ways, named: H (using the inverse of Hessian) and HIH (...
Paolinetta's user avatar
1 vote
0 answers
59 views

Using time dependent covariates in Gamma frailty Cox model

I have a dataset with repeated episodes per individual, trying to determine factors associated to the outcome of interest. I am planning to use a gamma frailty Cox model to account for intra ...
DURAL's user avatar
  • 21
1 vote
0 answers
160 views

Why did the log likelihood decrease with additional parameters?

I'm trying to decide the effect of some factors on the time for an event to happen . Specifically, I am looking at how long it takes for the subject to pass a test (recognize the stimulus) when ...
Hongyu Li's user avatar
0 votes
0 answers
192 views

Mixed Effects Model Using Censored Data

I am attempting to analyze left-censored hormone data collected in a repeated measures design, and am having some difficulty employing an appropriate method to account for the censored nature of the ...
HMDave's user avatar
  • 1
4 votes
1 answer
1k views

Survival analysis: Frailty vs Sandwich variance estimators

Question Can someone answer (in as non-technical terms as possible) whether or not frailty models and robust sandwich variance estimators are trying to solve the same problem in different contexts? ...
fen's user avatar
  • 87
0 votes
1 answer
530 views

random vs. stratified Cox model

What is the difference in interpretation of the effect estimates in a Cox model stratified by sex vs. with a random statement for sex? Thanks.
Anders M. Greve's user avatar
1 vote
0 answers
86 views

Frailty or median values in my cox proportional hazards model?

I am analysing data of woodpecker-made holes and I am interested in seeing what covariates and to what degree affect the survival of these holes (otherwise known as cavities). However, I encounter the ...
Alwin Hardenbol's user avatar
1 vote
0 answers
180 views

Cox model with frailty (partial loglikelihood and df)

I am fitting a Cox propotional hazard model with a frailty term using the survival package in R. When I remove a fixed efect, I ...
Nicolas's user avatar
  • 11
1 vote
1 answer
2k views

Can someone explain the meaning of "shared frailty" in survival analysis

Can someone explain the meaning of "shared frailty" in survival analysis in layman english ? a concrete example of where one would use this would also be very helpfull. thx kindly Stig
Stig Helweg-Jørgensen's user avatar
2 votes
0 answers
70 views

Responding to a reviewer: How to apply frailty to a Cox regression analysis in this situation

I am a medical doctor not a statistician. I have 60 patients who were assessed by 400 doctors (each doctor individually evaluated the clinical data on each patient). The doctor was then asked to say ...
GhostRider's user avatar
1 vote
0 answers
61 views

Comparison of longitudinal change in several parameters in same individuals: violations of survival analysis?

I am trying to compare 4 different (but correlated) parameters (biomarkers of a disease with continuous values) to identify which parameters would detect more deteriorating subjects and in a shorter ...
JG11235's user avatar
  • 121
5 votes
1 answer
489 views

Survival analysis for patients that have been subjected to multiple treatments

I have data for patients that were subjected to either one treatment or multiple treatments at various points in time and I need to analyse their survival times after treatments. This of course means ...
sztal's user avatar
  • 1,191
1 vote
1 answer
1k views

Unobserved heterogeneity in Cox model

I have some questions about the Cox model and unobserved heterogeneity. I work on a sample of firms divided in two categories: cooperatives and corporations. I want to test the influence of some ...
Justine's user avatar
  • 13
1 vote
1 answer
959 views

Software for survival regression with interval censoring and frailty

I'm conducting regression analysis on sleeping time data. The data is survey data and the answer possibilities are of type "less than 4 h", "5 h", "6 h", etc. so they can be thought to be interval ...
Lars von Mond's user avatar
1 vote
0 answers
584 views

How to plot splines in a coxph model that includes a frailty term?

I have a Cox PH model including a smoothing spline and a frailty term as follows: fit<-coxph(Surv(start,end,exit) ~ x + pspline(z) + frailty(a)) When I run a ...
Conor Little's user avatar
2 votes
0 answers
100 views

Determine number of excess events in survival analysis

I have run a survival analysis on two group of people that saw different ads during an ad campaign. I would like to calculate the number of excess events that occurred due to the exposure to the ad. ...
Simon Hayward's user avatar
11 votes
2 answers
14k views

Precisely how does R's coxph() handle repeated measures?

Context I'm attempting to understand how R's coxph() accepts and handles repeated entries for subjects (or patient/customer if you prefer). Some call this Long format, others call it 'repeated ...
user avatar
2 votes
2 answers
329 views

Survival Analysis/Frailty Model

I am trying to build a probability model for the following situation: I have a very large dataset, whose rows are users and columns are the features. All the users visit a particular store X (once ...
PTDS's user avatar
  • 719
5 votes
0 answers
707 views

Survival analysis with Frailty on large dataset

I am trying to fit a survival analysis in R with non-recurrent events and time-varying coefficients. The baseline distribution is exponential or Weibull and the ...
Benjamin Christoffersen's user avatar
0 votes
1 answer
248 views

Frailty Models: Gamma distributed frailty and Inverse Gaussian distributed frailty

In modelling of frailty using assumptions distributions of frailty are Gamma distributed frailty and Inverse Gaussian distributed frailty. Frailty is unobservable risk factor of mortality. How to ...
Desak Ristia Kartika's user avatar
1 vote
0 answers
717 views

Model assumptions and diagnostics for proportional hazard regression model with frailty in R

I am wondering are there any assumptions that must be met in the proportional hazard regression model with frailty? I remember that in regular proportional hazard model without frailty all variables ...
Marcin's user avatar
  • 1,049
0 votes
0 answers
514 views

Result of the summary of the proportional hazard model with frailty in R

I am trying to fit coxph a model with frailty with syntax below: ...
Marcin's user avatar
  • 1,049
12 votes
2 answers
4k views

Should I bootstrap at the cluster level or the individual level?

I have a survival model with patients nested in hospitals that includes a random-effect for the hospitals. The random effect is gamma-distributed, and I am trying to report the 'relevance' of this ...
drstevok's user avatar
  • 560
1 vote
1 answer
611 views

Link function for log-logistic shared gamma frailty model

I've been asked to replicate a study that models an accelerated failure time survival model with a log-logistic distribution and gamma distributed frailty (a 'log-logistic shared gamma frailty model') ...
chrstnsn's user avatar
  • 167
1 vote
0 answers
85 views

Poor parameter estimation in frailty models

I fitted a one-parameter gamma shared frailty model with Weibull and exponential baseline hazards for recurrent event data (the dataset contained 80 subjects of which 16 patients had events (13 ...
Nrich Rich's user avatar
2 votes
1 answer
2k views

Survival analysis in SAS-is there a way to include a random effect with interval censored data?

I'm trying to use some form of survival analysis (e.g. accelerated failure time or proportional hazards) to study seed germination time. My data is interval censored (also called "grouped-time") and ...
Tarek.Elnaccash's user avatar
3 votes
0 answers
1k views

How to interpret the frailty terms in a coxph.penal model?

I have the following coxph model: Surv(Y) ~ genotype + treatment + age + frailty(batch) + genotype:frailty(batch) ...
f1r3br4nd's user avatar
  • 2,354
0 votes
0 answers
179 views

Frailty model using bootstrap sampling

Let say I have a 'kidney catheter' data set which is built in survival package. Data are about the recurrence times to infection, at the point of insertion of the ...
JRK's user avatar
  • 613
3 votes
1 answer
762 views

Proportional odds model with random effects

I have a survival data set. I want to see the cluster specific variation, which we usually can do by using Cox proportional hazard model with frailty. But, the constant hazard ratio assumption of Cox ...
Dihan's user avatar
  • 337
0 votes
1 answer
167 views

Estimate of parameter $\beta$

Suppose I've a set of information, ...
Dihan's user avatar
  • 337
2 votes
0 answers
1k views

Variance of a random effect in Cox PH

I want to fit a Cox PH model with random effect (Gamma frailty). Here is an example with 'kidney catheter' data set: ...
Dihan's user avatar
  • 337