Therneau, Terry M., Ph.D.
2015-Sep-22 18:09 UTC
[R] Accounting for correlated random effects in coxme
I've been away for a couple weeks and am now catching up on email. The issue is that the coxme code does not have conversions built-in for all of the possible types of sparse matrix. Since it assumes that the variance matrix must be symmetric, the non-neccarily-symmetric dgCMatrix class is not one that I had considered. You should transform it to dsCMatrix first, which is a symmetric class. Or if it is small enough, to a simple matrix. Terry T. On 09/22/2015 05:00 AM, r-help-request at r-project.org wrote:> I have a problem with running the mixed effects Cox regression model using > a distance matrix from a phylogeny rather than a pedigree. I searched > previous posts and didn't find any directly relevant previous posts. > > I am interested in using a mixed effects Cox regression model to determine > the best predictors of time to recruitment in 80 different reintroduced > plant populations representing a total of 31 species. I will like to > account for correlated random effects that result from phylogenetic > relationships amongst species. Dr. Therneau's 2015 article on Mixed Effects > Cox Models provide a very helpful template for me to do this with the coxme > function in R. In this article, the correlation structure due to genetic > relationships amongst individuals was defined using a kinship matrix > derived from a pedigree. Instead of a pedigree, I have a phylogeny for > these 31 species. Hence, I used the inverseA function in the MCMCglmm > package to generate an inverse additive genetic relatedness matrix from the > phylogeny for these 31 species. And then fed it in as input to the varlist > argument in my mixed effects cox regression model (using function coxme). I > got an error message (please see below). Based on the error, one thought I > had was to convert the inverseA matrix from a ?dgCMatrix? to ?bdsmatrix? > but this was not successful either. I have also unsuccessfully tried to use > a pairwise phylogenetic distance matrix. > > Is there a better way to do this? I basically just want to account for the > correlated random effects due to phylogenetic relatedness amongst the 31 > species represented in the dataset for the Cox regression model. Please > see my code below and I welcome suggestions on how best to make this work.