derive_summary_records: Add New Records Within By Groups Using Aggregation Functions

Description

It is not uncommon to have an analysis need whereby one needs to derive an analysis value (AVAL) from multiple records. The ADaM basic dataset structure variable DTYPE is available to indicate when a new derived records has been added to a dataset.

Usage

derive_summary_records(
  dataset = NULL,
  dataset_add,
  dataset_ref = NULL,
  by_vars,
  filter = NULL,
  filter_add = NULL,
  analysis_var,
  summary_fun,
  set_values_to,
  missing_values = NULL
)

Value

A data frame with derived records appended to original dataset.

Arguments

dataset

Input dataset

The variables specified by the by_vars argument are expected to be in the dataset.

dataset_add

Additional dataset

The variables specified for by_vars are expected. Observations from the specified dataset are going to be used to calculate and added as new records to the input dataset (dataset).

dataset_ref

Reference dataset

The variables specified for by_vars are expected. For each observation of the specified dataset a new observation is added to the input dataset.

by_vars

Grouping variables

Variables to consider for generation of groupwise summary records. Providing the names of variables in exprs() will create a groupwise summary and generate summary records for the specified groups.

Permitted Values: list of variables created by exprs() e.g. exprs(USUBJID, VISIT)

filter

Please use filter_add instead.

Filter condition as logical expression to apply during summary calculation. By default, filtering expressions are computed within by_vars as this will help when an aggregating, lagging, or ranking function is involved.

For example,

filter = (AVAL > mean(AVAL, na.rm = TRUE)) will filter all AVAL values greater than mean of AVAL with in by_vars.
filter = (dplyr::n() > 2) will filter n count of by_vars greater than 2.

filter_add

For example,

filter_add = (AVAL > mean(AVAL, na.rm = TRUE)) will filter all AVAL values greater than mean of AVAL with in by_vars.
filter_add = (dplyr::n() > 2) will filter n count of by_vars greater than 2.

analysis_var

Analysis variable.

Please use set_values_to instead.

summary_fun

Function that takes as an input the analysis_var and performs the calculation.

Please use set_values_to instead.

This can include built-in functions as well as user defined functions, for example mean or function(x) mean(x, na.rm = TRUE).

set_values_to

Variables to be set

The specified variables are set to the specified values for the new observations.

Set a list of variables to some specified value for the new records

LHS refer to a variable.
RHS refers to the values to set to the variable. This can be a string, a symbol, a numeric value, an expression or NA. If summary functions are used, the values are summarized by the variables specified for by_vars.

For example:

  set_values_to = exprs(
    AVAL = sum(AVAL),
    DTYPE = "AVERAGE",
  )

missing_values

Values for missing summary values

For observations of the reference dataset (dataset_ref) which do not have a complete mapping defined by the summarization defined in set_values_to. Only variables specified for set_values_to can be specified for missing_values.

Permitted Values: named list of expressions, e.g., exprs(AVAL = -9999)

Details

When all records have same values within by_vars then this function will retain those common values in the newly derived records. Otherwise new value will be set to NA.

Examples

Run this code

library(tibble)
library(dplyr)

adeg <- tribble(
  ~USUBJID,   ~EGSEQ, ~PARAM,             ~AVISIT,    ~EGDTC,             ~AVAL, ~TRTA,
  "XYZ-1001", 1,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:50", 385,   NA_character_,
  "XYZ-1001", 2,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:52", 399,   NA_character_,
  "XYZ-1001", 3,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:56", 396,   NA_character_,
  "XYZ-1001", 4,      "QTcF Int. (msec)", "Visit 2",  "2016-03-08T09:45", 384,   "Placebo",
  "XYZ-1001", 5,      "QTcF Int. (msec)", "Visit 2",  "2016-03-08T09:48", 393,   "Placebo",
  "XYZ-1001", 6,      "QTcF Int. (msec)", "Visit 2",  "2016-03-08T09:51", 388,   "Placebo",
  "XYZ-1001", 7,      "QTcF Int. (msec)", "Visit 3",  "2016-03-22T10:45", 385,   "Placebo",
  "XYZ-1001", 8,      "QTcF Int. (msec)", "Visit 3",  "2016-03-22T10:48", 394,   "Placebo",
  "XYZ-1001", 9,      "QTcF Int. (msec)", "Visit 3",  "2016-03-22T10:51", 402,   "Placebo",
  "XYZ-1002", 1,      "QTcF Int. (msec)", "Baseline", "2016-02-22T07:58", 399,   NA_character_,
  "XYZ-1002", 2,      "QTcF Int. (msec)", "Baseline", "2016-02-22T07:58", 410,   NA_character_,
  "XYZ-1002", 3,      "QTcF Int. (msec)", "Baseline", "2016-02-22T08:01", 392,   NA_character_,
  "XYZ-1002", 4,      "QTcF Int. (msec)", "Visit 2",  "2016-03-06T09:50", 401,   "Active 20mg",
  "XYZ-1002", 5,      "QTcF Int. (msec)", "Visit 2",  "2016-03-06T09:53", 407,   "Active 20mg",
  "XYZ-1002", 6,      "QTcF Int. (msec)", "Visit 2",  "2016-03-06T09:56", 400,   "Active 20mg",
  "XYZ-1002", 7,      "QTcF Int. (msec)", "Visit 3",  "2016-03-24T10:50", 412,   "Active 20mg",
  "XYZ-1002", 8,      "QTcF Int. (msec)", "Visit 3",  "2016-03-24T10:53", 414,   "Active 20mg",
  "XYZ-1002", 9,      "QTcF Int. (msec)", "Visit 3",  "2016-03-24T10:56", 402,   "Active 20mg"
) %>%
  mutate(
    ADTM = convert_dtc_to_dtm(EGDTC)
  )

# Summarize the average of the triplicate ECG interval values (AVAL)
derive_summary_records(
  adeg,
  dataset_add = adeg,
  by_vars = exprs(USUBJID, PARAM, AVISIT),
  set_values_to = exprs(
    AVAL = mean(AVAL, na.rm = TRUE),
    DTYPE = "AVERAGE"
  )
) %>%
  arrange(USUBJID, AVISIT)

# Derive more than one summary variable
derive_summary_records(
  adeg,
  dataset_add = adeg,
  by_vars = exprs(USUBJID, PARAM, AVISIT),
  set_values_to = exprs(
    AVAL = mean(AVAL),
    ADTM = max(ADTM),
    DTYPE = "AVERAGE"
  )
) %>%
  arrange(USUBJID, AVISIT) %>%
  select(-EGSEQ, -TRTA)

# Sample ADEG dataset with triplicate record for only AVISIT = 'Baseline'
adeg <- tribble(
  ~USUBJID,   ~EGSEQ, ~PARAM,             ~AVISIT,    ~EGDTC,             ~AVAL, ~TRTA,
  "XYZ-1001", 1,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:50", 385,   NA_character_,
  "XYZ-1001", 2,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:52", 399,   NA_character_,
  "XYZ-1001", 3,      "QTcF Int. (msec)", "Baseline", "2016-02-24T07:56", 396,   NA_character_,
  "XYZ-1001", 4,      "QTcF Int. (msec)", "Visit 2",  "2016-03-08T09:48", 393,   "Placebo",
  "XYZ-1001", 5,      "QTcF Int. (msec)", "Visit 2",  "2016-03-08T09:51", 388,   "Placebo",
  "XYZ-1001", 6,      "QTcF Int. (msec)", "Visit 3",  "2016-03-22T10:48", 394,   "Placebo",
  "XYZ-1001", 7,      "QTcF Int. (msec)", "Visit 3",  "2016-03-22T10:51", 402,   "Placebo",
  "XYZ-1002", 1,      "QTcF Int. (msec)", "Baseline", "2016-02-22T07:58", 399,   NA_character_,
  "XYZ-1002", 2,      "QTcF Int. (msec)", "Baseline", "2016-02-22T07:58", 410,   NA_character_,
  "XYZ-1002", 3,      "QTcF Int. (msec)", "Baseline", "2016-02-22T08:01", 392,   NA_character_,
  "XYZ-1002", 4,      "QTcF Int. (msec)", "Visit 2",  "2016-03-06T09:53", 407,   "Active 20mg",
  "XYZ-1002", 5,      "QTcF Int. (msec)", "Visit 2",  "2016-03-06T09:56", 400,   "Active 20mg",
  "XYZ-1002", 6,      "QTcF Int. (msec)", "Visit 3",  "2016-03-24T10:53", 414,   "Active 20mg",
  "XYZ-1002", 7,      "QTcF Int. (msec)", "Visit 3",  "2016-03-24T10:56", 402,   "Active 20mg"
)

# Compute the average of AVAL only if there are more than 2 records within the
# by group
derive_summary_records(
  adeg,
  dataset_add = adeg,
  by_vars = exprs(USUBJID, PARAM, AVISIT),
  filter_add = n() > 2,
  set_values_to = exprs(
    AVAL = mean(AVAL, na.rm = TRUE),
    DTYPE = "AVERAGE"
  )
) %>%
  arrange(USUBJID, AVISIT)