R/check_combo_dropped_drugs.R

In sutsabs/rwLoT: Line of Therapy Package

#' Check Combo Dropped Drugs
#'
#' Check_combo_dropped_drugs checks to see if we should advance to a new line if
#' a drug in a combo regimen is dropped and returns the line end date and
#' next line start date for the dropped combo drugs.
#' @param drug_summary a dataframe of drug summary table generated by \code{\link{get_drug_summary}}
#' @param line_end_reason a string phrase, explanation why the line ends
#' \itemize{
#'   \item Last row hit
#'   \item Passed discontinuation gap
#'   \item New line started with new drugs
#'   \item Entering continuation maintenance therapy
#' }
#' @return A list, line_name
#' @export
check_combo_dropped_drugs <-
  function(drug_summary,
           line_end_reason) {
    # Get the list of dropped and undropped drugs
    undropped_drugs <- drug_summary %>% filter(DROPPED == 0)
    dropped_drugs <- drug_summary %>% filter(DROPPED == 1)

    if (nrow(dropped_drugs) > 0) {
      line_end_date <- min(dropped_drugs$LAST_SEEN)
      line_next_start <- line_end_date + 1
      line_end_reason <- "Combo drug dropped"
    }

    if (nrow(dropped_drugs) > 0) {
      return(
        list(
          "line_end_date" = line_end_date,
          "line_next_start" = line_next_start,
          "line_end_reason" = line_end_reason
        )
      )
    } else {
      return(NA)
    }
  }