Separate 2 groups in Cox regression
Instalation
Required Packages
library(futile.logger)
library(ggplot2)
library(glmSparseNet)
library(survival)
# Some general options for futile.logger the debugging package
flog.layout(layout.format("[~l] ~m"))
options("glmSparseNet.show_message" = FALSE)
# Setting ggplot2 default theme as minimal
theme_set(ggplot2::theme_minimal())Prepare data
Separate using age as co-variate
(group cutoff is median calculated relative risk)
Kaplan-Meier survival results
## Call: survfit(formula = survival::Surv(time, status) ~ group, data = prognosticIndexDf)
##
## n events median 0.95LCL 0.95UCL
## Low risk - 1 13 4 NA 638 NA
## High risk - 1 13 8 464 268 NAPlot
A individual is attributed to low-risk group if its calculated relative risk (using Cox Proportional model) is below or equal the median risk.
The opposite for the high-risk groups, populated with individuals above the median relative-risk.
Separate using age as co-variate (group cutoff is 40% - 60%)
Kaplan-Meier survival results
## Call: survfit(formula = survival::Surv(time, status) ~ group, data = prognosticIndexDf)
##
## n events median 0.95LCL 0.95UCL
## Low risk - 1 11 3 NA 563 NA
## High risk - 1 10 7 359 156 NAPlot
A individual is attributed to low-risk group if its calculated relative risk (using Cox Proportional model) is below the median risk.
The opposite for the high-risk groups, populated with individuals above the median relative-risk.
Separate using age as co-variate (group cutoff is 60% - 40%)
This is a special case where you want to use a cutoff that includes some sample on both high and low risks groups.
resAge6040 <- separate2GroupsCox(
chosenBetas = c(age = 1, 0),
xdata,
ydata,
probs = c(.6, .4),
stopWhenOverlap = FALSE
)## Warning in buildPrognosticIndexDataFrame(ydata, probs, stopWhenOverlap, : The cutoff values given to the function allow for some over samples in both groups, with:
## high risk size (15) + low risk size (16) not equal to xdata/ydata rows (31 != 26)
##
## We are continuing with execution as parameter `stopWhenOverlap` is FALSE.
## note: This adds duplicate samples to ydata and xdata xdataKaplan-Meier survival results
## Kaplan-Meier results## Call: survfit(formula = survival::Surv(time, status) ~ group, data = prognosticIndexDf)
##
## n events median 0.95LCL 0.95UCL
## Low risk - 1 16 5 NA 638 NA
## High risk - 1 15 9 475 353 NAPlot
A individual is attributed to low-risk group if its calculated relative risk (using Cox Proportional model) is below the median risk.
The opposite for the high-risk groups, populated with individuals above the median relative-risk.
Session Info
## R version 4.6.0 (2026-04-24)
## Platform: x86_64-pc-linux-gnu
## Running under: Ubuntu 24.04.4 LTS
##
## Matrix products: default
## BLAS: /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3
## LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.26.so; LAPACK version 3.12.0
##
## locale:
## [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
## [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
## [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
## [7] LC_PAPER=en_US.UTF-8 LC_NAME=C
## [9] LC_ADDRESS=C LC_TELEPHONE=C
## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
##
## time zone: Etc/UTC
## tzcode source: system (glibc)
##
## attached base packages:
## [1] grid parallel stats4 stats graphics grDevices utils
## [8] datasets methods base
##
## other attached packages:
## [1] glmnet_5.0 VennDiagram_1.8.2
## [3] reshape2_1.4.5 forcats_1.0.1
## [5] Matrix_1.7-5 glmSparseNet_1.31.0
## [7] TCGAutils_1.33.2 curatedTCGAData_1.35.0
## [9] MultiAssayExperiment_1.39.0 SummarizedExperiment_1.43.0
## [11] Biobase_2.73.1 GenomicRanges_1.65.0
## [13] Seqinfo_1.3.0 IRanges_2.47.2
## [15] S4Vectors_0.51.3 BiocGenerics_0.59.7
## [17] generics_0.1.4 MatrixGenerics_1.25.0
## [19] matrixStats_1.5.0 futile.logger_1.4.9
## [21] survival_3.8-6 ggplot2_4.0.3
## [23] dplyr_1.2.1 BiocStyle_2.41.0
##
## loaded via a namespace (and not attached):
## [1] RColorBrewer_1.1-3 sys_3.4.3
## [3] jsonlite_2.0.0 shape_1.4.6.1
## [5] magrittr_2.0.5 GenomicFeatures_1.65.0
## [7] farver_2.1.2 rmarkdown_2.31
## [9] BiocIO_1.23.3 vctrs_0.7.3
## [11] memoise_2.0.1 Rsamtools_2.29.0
## [13] RCurl_1.98-1.19 rstatix_0.7.3
## [15] htmltools_0.5.9 S4Arrays_1.13.0
## [17] BiocBaseUtils_1.15.1 progress_1.2.3
## [19] AnnotationHub_4.3.1 lambda.r_1.2.4
## [21] curl_7.1.0 broom_1.0.13
## [23] Formula_1.2-5 SparseArray_1.13.2
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## [47] abind_1.4-8 compiler_4.6.0
## [49] bit64_4.8.2 withr_3.0.3
## [51] S7_0.2.2 backports_1.5.1
## [53] BiocParallel_1.47.0 carData_3.0-6
## [55] DBI_1.3.0 ggsignif_0.6.4
## [57] biomaRt_2.69.0 rappdirs_0.3.4
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