R/count_patients.R

In patrickwu510/ddiwas: What the Package Does (One Line, Title Case)

#' Get number of cases and controls
#' Last updated: 2020-06-21
#'
#' @param covariates A tibble
#' @param medications A tibble
#' @return A tibble \code{cohort_count}
#' @export

count_patients <- function(medications, covariates) {

  ##only keep covariates that are in `medications`
  covariates <- covariates %>%
    filter(person_id %in% medications$person_id)
  ##check if there are any patients that appear twice in table
  num_rows <- nrow(covariates)
  unique_patients <- n_distinct(covariates$person_id)
  ##get number of cases and controls
  covariates1 <- covariates %>% group_by(groupc) %>% tally()
  num_controls <- covariates1[1,2]
  num_cases <- covariates1[2,2]
  ##create tibble with all results
  cohort_count <- tibble(num_rows = num_rows,
                         unique_patients = unique_patients,
                         num_controls = num_controls,
                         num_cases = num_cases)
  cohort_count
}