ratio_summary {gtsummary}

Summarize the ratio of two variables

Description

This helper, to be used with tbl_custom_summary(), creates a function computing the ratio of two continuous variables and its confidence interval.

Usage

ratio_summary(numerator, denominator, na.rm = TRUE, conf.level = 0.95)

Arguments

numerator

(string)
String indicating the name of the variable to be summed for computing the numerator.

denominator

(string)
String indicating the name of the variable to be summed for computing the denominator.

na.rm

(scalar logical)
Should missing values be removed before summing the numerator and the denominator? (default is TRUE)

conf.level

(scalar numeric)
Confidence level for the returned confidence interval. Must be strictly greater than 0 and less than 1. Default to 0.95, which corresponds to a 95 percent confidence interval.

Details

Computed statistics:

• {num} sum of the variable defined by numerator

• {denom} sum of the variable defined by denominator

• {ratio} ratio of num by denom

• {conf.low} lower confidence interval

• {conf.high} upper confidence interval

Confidence interval is computed with stats::poisson.test(), if and only if num is an integer.

Author(s)

Joseph Larmarange

Examples

# Example 1 ----------------------------------
trial |>
  tbl_custom_summary(
    include = c("stage", "grade"),
    by = "trt",
    stat_fns = ~ ratio_summary("response", "ttdeath"),
    statistic = ~"{ratio} [{conf.low}; {conf.high}] ({num}/{denom})",
    digits = ~ c(ratio = 3, conf.low = 2, conf.high = 2),
    overall_row = TRUE,
    overall_row_label = "All stages & grades"
  ) |>
  bold_labels() |>
  modify_footnote(all_stat_cols() ~ "Ratio [95% CI] (n/N)")