Skip to contents

Integration Point: Response - Continuous Outcome with Repeated Measures

Gabriel Potvin

January 16, 2025

IntegrationPointResponseRepeatedMeasures.Rmd

←\leftarrow Go back to the Integration Point: Response page

This integration point and outcome is currently available for the Two Arm Confirmatory Study Objective.

Input Variables

When creating a custom R script, you can optionally use specific variables provided by East Horizon’s engine itself. These variables are automatically available and do not need to be set by the user, except for the UserParam variable. Refer to the table below for the variables that are available for this integration point and outcome.

Variable Type Description
NumSub Integer Number of subjects in the trial.
TreatmentID Vector of Integer Vector of length NumSub, indicating the allocation of subjects to arms. Index 0 represents placebo/control. For example, [0, 0, 1] indicates three subjects: two in the control group and one experimental.
NumVisit Integer Number of visits.
Inputmethod Integer Two options:
– 0: The mean and SD values represent actual values.
– 1: They represent an expected change from baseline at each visit rather than the true means.
VisitTime Vector of Numeric Vector of length NumVisit, indicating the visit times.
MeanControl Vector of Numeric Vector of length NumVisit, indicating the control mean for each visit.
MeanTrt Vector of Numeric Vector of length NumVisit, indicating the treatment mean for each visit.
StdDevControl Vector of Numeric Vector of length NumVisit, indicating the control standard deviation for each visit.
StdDevTrt Vector of Numeric Vector of length NumVisit, indicating the treatment standard deviation for each visit.
CorrMat Matrix of Numeric Matrix of size NumVisit ×\timesNumVisit, indicating the correlation between all visits.
UserParam List Contains all user-defined parameters specified in the East Horizon interface (refer to the Instructions section). To access these parameters in your R code, use the syntax: UserParam$NameOfTheVariable, replacing NameOfTheVariable with the appropriate parameter name.

Expected Output Variable

East Horizon expects an output of a specific type. Refer to the table below for the expected output for this integration point:

Type Description
List A named list containing Response1, Response2, …, ResponseNumVisit, and ErrorCode.

Expected Members of the Output List

Members Type Description
Response1 Vector of Numeric Vector of length NumSub, containing the generated responses for all subjects for the first visit.
Response2 Vector of Numeric Vector of length NumSub, containing the generated responses for all subjects for the second visit.
… Responses for additional visits follow the same format, incrementing the visit number (e.g., Response3, Response4, etc.).
ResponseNumVisit Vector of Numeric Final vector of length NumSub, containing the generated responses for all subjects for the last visit. NumVisit should be replaced by the number of visits.
ErrorCode Integer Optional. Can be used to handle errors in your script:
– 0: No error.
– Positive Integer: Nonfatal error, the current simulation will be aborted, but the next simulation will proceed.
– Negative Integer: Fatal error, no further simulations will be attempted.

Minimal Template

Your R script could contain a function such as this one, with a name of your choice. All input variables must be declared, even if they are not used in the script. We recommend always declaring UserParam as a default NULL value in the function arguments, as this will ensure that the same function will work regardless of whether the user has specified any custom parameters in East Horizon.

GenerateResponse <- function( NumSub, NumVisit, TreatmentID, Inputmethod, VisitTime, MeanControl, 
                              MeanTrt, StdDevControl, StdDevTrt, CorrMat, UserParam = NULL )
{
  nError            <- 0 # Error handling (no error)
  vOutResponse      <- c()
  lReturn           <- list()
  
  # Add code to simulate the patient data as desired.  
  # Example of how to create the return list with Response1, Response2, ..., ResponseNumVisit.
  # Store the generated continuous response values in a vector called vOutResponse for each subject.
  # Store the response vector in a list called lReturn for each visit.
  for(i in 1:NumVisit)
  {
      strVisitName              <- paste0( "Response", i ) # Response1, Response2, ..., ResponseNumVisit
      vOutResponse              <- rep( 0, NumSub )  # Initializing response array to 0 
      lReturn[[ strVisitName ]] <- as.double( vOutResponse )
  }
    
  lReturn$ErrorCode <- as.integer( nError )
  return( lReturn )
}

A detailed template with step-by-step explanations is available here: SimulatePatientOutcome.RepeatedMeasures.R

Example

Explore the following example for more context:

  1. 2-Arm, Normal Outcome, Repeated Measures - Patient Simulation