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How to use R function tableby() to get the strata printed as extra columns instead of extra rows, or another way to accomplish the same thing?

I would like to use the R function tableby() to get the strata printed as extra columns instead of extra rows, or find another way to accomplish the same thing. I show an example with the mockstudy data below. However, my actual dataset has many more variables (both categorical and numeric), so the different format makes much more sense. Plus, I want to show the number of observations in each subcategory (e.g., Treatment Arm A and Male, Treatment Arm A and Female, etc.).

As a short example, I have the following code in an Rmardown file to generate a table with summary statistics using the tableby() function from the arsenal package in R.

title: "Testing tableby() output" output: html_document date: "2023-11-29"

knitr::opts_chunk$set(echo = TRUE)



library(arsenal) # for tableby()
require(knitr)
data(mockstudy) # load data

summary(tableby(sex ~ age + bmi, strata = arm, subset = arm %in% c("A: IFL", "F: FOLFOX"), data = mockstudy))

Which generates the following output:

Rmarkdown output showing table

However, I would like a table arranged in the following way, with the correct N at the top of each column:

Example headers of table I want

Is there a way to do this with tableby() or another function in another R package?

Solution

  • With arsenal and tableby(), I believe your strata argument (strata=arm) is the best way to do it.

    Instead, I’d recommend looking into something like tblstrata() in the gtsummary package; it would give you something that looks like this: Example from gtsummary documentation.

    Using the same example you gave, the code would be:

    table_example <-
  mockstudy %>%
  tbl_strata(
    strata = arm,
    .tbl_fun =
      ~ .x %>%
        tbl_summary(by = sex, missing = "no") %>%
        add_n(),
    .header = "**{strata}**, N = {n}"
  )