AOVT03

ANCOVA with Consideration of Interaction

---

Output

This example will focus on data from multiple visits and take the interaction between visits and arms into consideration.

Standard Table

Preview

result <- basic_table(show_colcounts = TRUE) %>%
  split_cols_by("ARMCD", ref_group = "ARM A") %>%
  split_rows_by("PARAM", split_fun = drop_split_levels) %>%
  summarize_ancova(
    vars = "CHG",
    variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),
    conf_level = 0.95,
    var_labels = "WEEK 1 DAY 8",
    table_names = "WEEK 1 DAY 8",
    interaction_y = "WEEK 1 DAY 8",
    interaction_item = "AVISIT"
  ) %>%
  summarize_ancova(
    vars = "CHG",
    variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),
    conf_level = 0.95,
    var_labels = "WEEK 2 DAY 15",
    table_names = "WEEK 2 DAY 15",
    interaction_y = "WEEK 2 DAY 15",
    interaction_item = "AVISIT"
  ) %>%
  summarize_ancova(
    vars = "CHG",
    variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),
    conf_level = 0.95,
    var_labels = "WEEK 5 DAY 36",
    table_names = "WEEK 5 DAY 36",
    interaction_y = "WEEK 5 DAY 36",
    interaction_item = "AVISIT"
  ) %>%
  build_table(adqs_in, alt_counts_df = adsl)

result

                                    ARM A        ARM B           ARM C    
                                   (N=134)      (N=134)         (N=132)   
——————————————————————————————————————————————————————————————————————————
BFI All Questions                                                         
  WEEK 1 DAY 8                                                            
    n                                68           73              62      
    Adjusted Mean                   4.34         5.96            3.90     
    Difference in Adjusted Means                 1.62            -0.44    
      95% CI                                 (-1.75, 4.98)   (-3.94, 3.06)
      p-value                                   0.3460          0.8059    
  WEEK 2 DAY 15                                                           
    n                                68           73              62      
    Adjusted Mean                   12.99        11.23           9.86     
    Difference in Adjusted Means                 -1.76           -3.13    
      95% CI                                 (-5.12, 1.60)   (-6.64, 0.37)
      p-value                                   0.3048          0.0795    
  WEEK 5 DAY 36                                                           
    n                                68           73              62      
    Adjusted Mean                   23.88        23.08           28.21    
    Difference in Adjusted Means                 -0.81           4.33     
      95% CI                                 (-4.17, 2.56)   (0.83, 7.83) 
      p-value                                   0.6383          0.0155    
Fatigue Interference                                                      
  WEEK 1 DAY 8                                                            
    n                                68           73              62      
    Adjusted Mean                   5.97         5.19            5.21     
    Difference in Adjusted Means                 -0.78           -0.76    
      95% CI                                 (-4.17, 2.61)   (-4.30, 2.78)
      p-value                                   0.6522          0.6729    
  WEEK 2 DAY 15                                                           
    n                                68           73              62      
    Adjusted Mean                   11.39        9.42            9.55     
    Difference in Adjusted Means                 -1.96           -1.84    
      95% CI                                 (-5.35, 1.43)   (-5.37, 1.70)
      p-value                                   0.2560          0.3084    
  WEEK 5 DAY 36                                                           
    n                                68           73              62      
    Adjusted Mean                   22.79        25.37           23.43    
    Difference in Adjusted Means                 2.58            0.64     
      95% CI                                 (-0.81, 5.97)   (-2.89, 4.18)
      p-value                                   0.1353          0.7212    

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result <- basic_table(show_colcounts = TRUE) %>%

split_cols_by("ARMCD", ref_group = "ARM A") %>%

split_rows_by("PARAM", split_fun = drop_split_levels) %>%

summarize_ancova(

vars = "CHG",

variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),

conf_level = 0.95,

var_labels = "WEEK 1 DAY 8",

table_names = "WEEK 1 DAY 8",

interaction_y = "WEEK 1 DAY 8",

interaction_item = "AVISIT"

) %>%

summarize_ancova(

vars = "CHG",

variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),

conf_level = 0.95,

var_labels = "WEEK 2 DAY 15",

table_names = "WEEK 2 DAY 15",

interaction_y = "WEEK 2 DAY 15",

interaction_item = "AVISIT"

) %>%

summarize_ancova(

vars = "CHG",

variables = list(arm = "ARMCD", covariates = c("BASE", "AVISIT", "AVISIT*ARMCD")),

conf_level = 0.95,

var_labels = "WEEK 5 DAY 36",

table_names = "WEEK 5 DAY 36",

interaction_y = "WEEK 5 DAY 36",

interaction_item = "AVISIT"

) %>%

build_table(adqs_in, alt_counts_df = adsl)

result

_webr_editor_2 = Object {code: "result <- basic_table(show_colcounts = TRUE) %>%\n …uild_table(adqs_in, alt_counts_df = adsl)\n\nresult", options: Object, indicator: Ke}

Data Setup

library(tern)
library(dplyr)

adsl <- random.cdisc.data::cadsl
adqs <- random.cdisc.data::cadqs

adqs_in <- adqs %>%
  filter(AVISIT %in% c("WEEK 1 DAY 8", "WEEK 2 DAY 15", "WEEK 5 DAY 36")) %>%
  droplevels() %>%
  filter(PARAM %in% c("BFI All Questions", "Fatigue Interference")) %>%
  mutate(CHG = ifelse(BMEASIFL == "Y", CHG, NA)) # only analyze evaluable population

Reproducibility

Timestamp

[1] "2025-04-09 18:06:12 UTC"

Session Info

─ Session info ───────────────────────────────────────────────────────────────
 setting  value
 version  R version 4.4.2 (2024-10-31)
 os       Ubuntu 24.04.1 LTS
 system   x86_64, linux-gnu
 ui       X11
 language (EN)
 collate  en_US.UTF-8
 ctype    en_US.UTF-8
 tz       Etc/UTC
 date     2025-04-09
 pandoc   3.6.3 @ /usr/bin/ (via rmarkdown)
 quarto   1.6.43 @ /usr/local/bin/quarto

─ Packages ───────────────────────────────────────────────────────────────────
 package           * version     date (UTC) lib source
 backports           1.5.0       2024-05-23 [1] RSPM
 brio                1.1.5       2024-04-24 [1] RSPM
 broom               1.0.8       2025-03-28 [1] RSPM
 checkmate           2.3.2       2024-07-29 [1] RSPM
 cli                 3.6.4       2025-02-13 [1] RSPM
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 digest              0.6.37      2024-08-19 [1] RSPM
 dplyr             * 1.1.4       2023-11-17 [1] RSPM
 emmeans             1.11.0      2025-03-20 [1] RSPM
 estimability        1.5.1       2024-05-12 [1] RSPM
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 lattice             0.22-7      2025-04-02 [2] CRAN (R 4.4.2)
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 magrittr          * 2.0.3       2022-03-30 [1] RSPM
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 Matrix              1.7-3       2025-03-11 [1] CRAN (R 4.4.2)
 multcomp            1.4-28      2025-01-29 [1] RSPM
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 mvtnorm             1.3-3       2025-01-10 [1] RSPM
 nestcolor           0.1.3.9000  2025-04-09 [1] https://p~
 pillar              1.10.2      2025-04-05 [1] RSPM
 pkgcache            2.2.3       2024-09-12 [1] RSPM
 pkgconfig           2.0.3       2019-09-22 [1] RSPM
 processx            3.8.6       2025-02-21 [1] RSPM
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 purrr               1.0.4       2025-02-05 [1] RSPM
 R6                  2.6.1       2025-02-15 [1] RSPM
 random.cdisc.data   0.3.16.9002 2025-04-09 [1] https://p~
 rbibutils           2.3         2024-10-04 [1] RSPM
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 stringi             1.8.7       2025-03-27 [1] RSPM
 stringr             1.5.1       2023-11-14 [1] RSPM
 survival            3.8-3       2024-12-17 [2] CRAN (R 4.4.2)
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 [1] /usr/local/lib/R/site-library
 [2] /usr/local/lib/R/library
 [3] /github/home/R/x86_64-pc-linux-gnu-library/4.4
 * ── Packages attached to the search path.

──────────────────────────────────────────────────────────────────────────────

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