Dataset Contents

{admiralophtha} suggests to populate ADOE with general miscellaneous ophthalmology parameters. Any efficacy endpoint-related parameters (eg. BCVA tests) should be placed in separate datasets (eg. ADBCVA).

Required Packages

The examples of this vignette require the following packages.

library(dplyr)
library(admiral)
library(pharmaversesdtm)
library(admiraldev)
library(admiralophtha)

Initial set up of ADOE

As with all BDS ADaM datasets, one should start from the OE SDTM, where only the general ophthalmology records are of interest. For the purposes of the next two sections, we shall be using the {admiral} OE and ADSL test data. We will also require a lookup table for the mapping of parameter codes.

Note: to simulate an ophthalmology study, we add a randomly generated STUDYEYE variable to ADSL, but in practice STUDYEYE will already have been derived using derive_var_studyeye().

data("oe_ophtha")
data("admiral_adsl")

# Add STUDYEYE to ADSL to simulate an ophtha dataset
adsl <- admiral_adsl %>%
  as.data.frame() %>%
  mutate(STUDYEYE = sample(c("LEFT", "RIGHT"), n(), replace = TRUE)) %>%
  convert_blanks_to_na()

oe <- convert_blanks_to_na(oe_ophtha) %>%
  ungroup()

# ---- Lookup table ----

# Assign PARAMCD, PARAM, and PARAMN
param_lookup <- tibble::tribble(
  ~OETESTCD, ~OECAT, ~OESCAT, ~AFEYE, ~PARAMCD, ~PARAM, ~PARAMN,
  "CSUBTH", "OPHTHALMIC ASSESSMENTS", "SD-OCT CST SINGLE FORM", "Study Eye", "SCSUBTH", "Study Eye Center Subfield Thickness (um)", 1, # nolint
  "CSUBTH", "OPHTHALMIC ASSESSMENTS", "SD-OCT CST SINGLE FORM", "Fellow Eye", "FCSUBTH", "Fellow Eye Center Subfield Thickness (um)", 2, # nolint
  "DRSSR", "OPHTHALMIC ASSESSMENTS", "SD-OCT CST SINGLE FORM", "Study Eye", "SDRSSR", "Study Eye Diabetic Retinopathy Severity", 3, # nolint
  "DRSSR", "OPHTHALMIC ASSESSMENTS", "SD-OCT CST SINGLE FORM", "Fellow Eye", "FDRSSR", "Fellow Eye Diabetic Retinopathy Severity", 4, # nolint
)

Following this setup, the programmer can start constructing ADOE. The first step is to subset OE to only general ophthalmology parameters. Then, one can merge the resulting dataset with ADSL. This is required for two reasons: firstly, STUDYEYE is crucial in the mapping of AFEYE and PARAMCD’s. Secondly, the treatment start date (TRTSDT) is also a prerequisite for the derivation of variables such as Analysis Day (ADY).

adsl_vars <- exprs(TRTSDT, TRTEDT, TRT01A, TRT01P, STUDYEYE)

adoe <- oe %>%
  filter(
    OETESTCD %in% c("CSUBTH", "DRSSR")
  ) %>%
  derive_vars_merged(
    dataset_add = adsl,
    new_vars = adsl_vars,
    by_vars = get_admiral_option("subject_keys")
  )

The next item of business is to derive AVAL, AVALU, and DTYPE. In this example, due to the small number of parameters their derivation is trivial. AFEYE is also created in this step using the function derive_var_afeye(). To determine the affected eye, this function compares OELAT to the STUDYEYE variable created from the previous step.

adoe <- adoe %>%
  # Calculate AVAL, AVALC, AVALU and DTYPE
  mutate(
    AVAL = OESTRESN,
    AVALC = OESTRESC,
    AVALU = OESTRESU,
    DTYPE = NA_character_
  ) %>%
  # Derive AFEYE needed for PARAMCD derivation
  derive_var_afeye(loc_var = OELOC, lat_var = OELAT, loc_vals = c("EYE", "RETINA"))

Further Derivations of Standard BDS Variables

The user is invited to consult the article on creating a BDS dataset from SDTM to learn how to add standard BDS variables to ADOE.

Example Script