summary row with gtsummary - gtsummary

Question

I am trying to create a table of events with gtsummary and I would like to obtain a final row counting the events of the previous rows. add_overall() and add_n() do add the total but in a column, counting the same event across groups but not the overall events.
I created this example.
x1 <- sample(c("No", "Yes"), 30, replace = TRUE, prob = c(0.85, 0.15))
x2 <- sample(c("No", "Yes"), 30, replace = TRUE, prob = c(0.9, 0.1))
x3 <- sample(c("No", "Yes"), 30, replace = TRUE, prob = c(0.75, 0.25))
y <- sample(c("A", "B"), 30, replace = TRUE, prob = c(0.5, 0.5))
df <- data.frame(as_factor(x1), as_factor(x2), as_factor(x3), as_factor(y))
colnames(df) <-c("event_1", "event_2", "event_3", "group")
tbl_summary(df, by=group, statistic = all_categorical() ~ "{n}")
example
I tried using summary_rows() function from gt package after converting the table to a gt object but there is an error when summarising because these variables are factors.
Any other ideas?

Answer 1

You can do this by adding a new variable to your data frame that is the row sum of each of the events. Then you can display that variable's sum in the summary table. Example below!
library(gtsummary)
#> #Uighur
library(tidyverse)
df <-
data.frame(
event_1 = sample(c(FALSE, TRUE), 30, replace = TRUE, prob = c(0.85, 0.15)),
event_2 = sample(c(FALSE, TRUE), 30, replace = TRUE, prob = c(0.9, 0.1)),
event_3 = sample(c(FALSE, TRUE), 30, replace = TRUE, prob = c(0.75, 0.25)),
group = sample(c("A", "B"), 30, replace = TRUE, prob = c(0.5, 0.5))
) |>
rowwise() |>
mutate(Total = sum(event_1, event_2, event_3))
tbl_summary(
df,
by = group,
type = Total ~ "continuous",
statistic =
list(all_categorical() ~ "{n}",
all_continuous() ~ "{sum}")
) |>
as_kable() # convert to kable to display on stack overflow
Characteristic
A, N = 16
B, N = 14
event_1
4
4
event_2
1
2
event_3
7
6
Total
12
12
Created on 2023-01-12 with reprex v2.0.2

Answer 2

Thank you so much (great package gtsummary). That works! I had some trouble summing over factors. If variables are factors the code
mutate(Total = sum(event_1=="Yes", event_2=="Yes", event_3=="Yes"))
does it.