Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [frailty]

52 questions
15
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1 answer

How to generate predicted survivor curves from frailty models (using R coxph)?

I want to compute predicted survivor function for a Cox proportional hazards model with frailty terms [using survival package]. It appears that when frailty terms are in the model, the predicted survivor function cannot be computed. ## Example…
ledzep
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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 term on a scale that is easily understood. I have…
drstevok
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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 measures'. See for example the data set that includes…
Quetzalcoatl
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9
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1 answer

Which model should I use for Cox proportional hazards with paired data?

I am hoping someone can help me with which model (frailty, strata or cluster) I should use for my data. I have paired data so I need to take that into account when modelling the Cox PH and am unsure which model will give me a more accurate…
Emma
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8
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1 answer

Any ideas about how to analyze survival data with pseudo-replication (dependent data)?

I am a student, working with a team on a large-scale ecological experiment. We want to analyze survival data which has been derived from an experimental design with some pseudo-replication. This pseudo-replication was not discovered, unfortunately,…
annemphillip
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6
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1 answer

EM algorithm R code on Cox PH model with frailty

Let say I have a 'kidney catheter' data set. Data are about the recurrence times to infection, at the point of insertion of the catheter, for kidney patients using portable dialysis equipment. Catheters may be removed for reasons other than…
Dihan
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5
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1 answer

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 that some patients appears only once in the…
sztal
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5
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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 frailty distribution is gamma distributed. I have roughly 900.000 rows. So far I have…
Benjamin Christoffersen
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4
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1 answer

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? That problem being that estimated standard errors…
fen
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4
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2 answers

How should I analyze data on birth intervals of women?

I have data on birth intervals of women. Birth interval refers to the time interval from one child's birth date until the next child's birth date. Here, dependent variable is the birth interval, defined as the length of time between two successive…
Jahid
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4
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2 answers

How to conduct conditional Cox regression for matched case-control study?

I am attempting to find a program that will let me conduct Cox regression on my matched case-control dataset. Please assist. p.s. I have STATA, SPSS, and MedCalc
Jay
3
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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. (2008) argued that one should use a mixture of…
Cardinal
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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 has a random effect (also called "frailty"). How…
Tarek.Elnaccash
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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) batch is a random effect (two replicates of the experiment were done with different subjects). Events can only happen once per…
f1r3br4nd
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1 answer

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 datasets using coxme(). See the following example: # needed to tidy the coxme object install.packages("remotes");…
schotti
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