R/gather_results.R

In rclinicaltrials: Download Aggregate Trial Information and Results from ClinicalTrials.gov

#' Parses results from an xml object downloaded from clinicaltrials.gov
#'
#' Results of a clinical study are stored in a particular way. This reads and
#' organizes the information and returns it as a list of dataframes. Throws an error if the xml has no \code{clinical_results} node.
#'
#' @param parsed A parsed XML object, as returned by \code{XML::xmlParse}
#' @keywords Internal
#'
#' @return A list of \code{data.frame}s, participant flow, baseline data,
#'   outcome results
#'

gather_results <- function(parsed){

  check <- tryCatch(parsed[["//clinical_results"]],  error = function(e) {
    return(NULL)
  })
  if(is.null(check)) return(list(
    participant_flow = NULL,
    baseline_data = NULL,
    outcome_data = NULL
  ))

  this_nct_id <- XML::xmlValue(parsed[["//nct_id"]])

  ## participant flow


  gp_look <- get_group_lookup(parsed, "//participant_flow/group_list")
  period <- parsed["//period_list/period"]

  flow_table <- do.call(plyr::rbind.fill, XML::xmlApply(period, function(node){

    cbind(
      title = XML::xmlValue(node[["title"]]),
      do.call(plyr::rbind.fill, XML::xmlApply(node[["milestone_list"]], function(n0){

        cbind(status = XML::xmlValue(n0[["title"]]),
              data.frame(t(XML::xmlSApply(n0[["participants_list"]], XML::xmlAttrs)), stringsAsFactors = FALSE, row.names = 1:length(gp_look)))

      }))
    )

  }))



  flow_table$arm <- gp_look[flow_table$group_id]
  flow_table$nct_id <- this_nct_id


  ## baseline

  gp_look <- get_group_lookup(parsed, "//baseline/group_list")

  measures <- parsed[["//baseline/measure_list"]]

  baseline_table <- do.call(plyr::rbind.fill, XML::xmlApply(measures, function(node){

    #outer most level: titles and units
    lank <- XML::xmlSApply(node, function(n){
      # category_list -> return sub-titles
      if(XML::xmlName(n) == "category_list"){

        do.call(plyr::rbind.fill, XML::xmlApply(n, function(n0){

          tmpRes <- XML::xmlApply(n0[["measurement_list"]], function(x){

            as.data.frame(t(XML::xmlAttrs(x)), stringsAsFactors = FALSE)

          })
          ResAdd <- do.call(plyr::rbind.fill, tmpRes)
          data.frame(
            cbind(
              subtitle = XML::xmlValue(n0),
              ResAdd,
              stringsAsFactors = FALSE),
            row.names = NULL, stringsAsFactors = FALSE)
        }))

      } else if(XML::xmlName(n) == "class_list"){

        do.call(plyr::rbind.fill, XML::xmlApply(n, function(n0){

          subtitle <- XML::xmlValue(n0[["title"]])
          tmpRes <- XML::xmlApply(n0[["category_list"]][["category"]][["measurement_list"]], function(x){

            as.data.frame(t(XML::xmlAttrs(x)), stringsAsFactors = FALSE)

          })
          ResAdd <- do.call(plyr::rbind.fill, tmpRes)
          data.frame(
            cbind(
              subtitle = subtitle,
              ResAdd,
              stringsAsFactors = FALSE),
            row.names = NULL, stringsAsFactors = FALSE)
        }))

      } else {

        XML::xmlValue(n)

      }
    })

    names(lank)[names(lank) == "class_list"] <- "category_list"
    target <- lank$category_list
    fillout <- lank[names(lank) != "category_list"]
    cbind(fillout, target)

  }))

  baseline_table$arm <- gp_look[baseline_table$group_id]
  baseline_table$nct_id <- this_nct_id

  ## outcomes

  #parsed_out <- xml2::xml_find_all(x, ".//outcome")

  all_results_list <- XML::xmlApply(parsed[["//clinical_results/outcome_list"]], function(parsed_out){

    gp_look <- get_group_lookup(parsed_out, "group_list")

    measures <- parsed_out[["measure_list"]]
    analysis <- parsed_out[["analysis_list"]]

    results_titles <- XML::xmlApply(parsed_out, function(node){

      if(XML::xmlName(node) %in% c("group_list", "measure_list", "analysis_list")) return(NULL) else {

        XML::xmlValue(node)

      }

    })

    if(!is.null(measures)) {
      results_table <- do.call(plyr::rbind.fill, XML::xmlApply(measures, function(node){

        #outer most level: titles and units
        lank <- XML::xmlSApply(node, function(n){
          # category_list -> return sub-titles
          if(XML::xmlName(n) == "category_list"){

            do.call(plyr::rbind.fill, XML::xmlApply(n, function(n0){
              data.frame(
                cbind(
                  subtitle = XML::xmlValue(n0),
                  t(XML::xmlSApply(n0[["measurement_list"]], XML::xmlAttrs)),
                  stringsAsFactors = FALSE),
                row.names = NULL, stringsAsFactors = FALSE)
            }))

          } else {

            XML::xmlValue(n)

          }
        })

        target <- lank$category_list
        fillout <- lank[names(lank) != "category_list"]
        cbind(fillout, target)

      }))

      results_table$arm <- gp_look[results_table$group_id]

      measures_table <- cbind(results_titles[!names(results_titles) %in% c("group_list", "measure_list", "analysis_list")],
            results_table)

    } else measures_table <- data.frame(results_titles[!names(results_titles) %in% c("group_list", "measure_list", "analysis_list")])

    if(!is.null(analysis)){

      analysis_table <- do.call(plyr::rbind.fill, XML::xmlApply(analysis, function(node){

        lank <- as.data.frame(XML::xmlApply(node, function(n){

          if(XML::xmlName(n) == "group_id_list"){

            data.frame(group_id = XML::xmlSApply(n, XML::xmlValue), stringsAsFactors = FALSE)

          } else {

            tmp <- data.frame(XML::xmlValue(n), stringsAsFactors = FALSE)
            colnames(tmp) <- XML::xmlName(n)
            tmp

          }
        }), stringsAsFactors = FALSE)

      }))

      analysis_table$arm <- gp_look[analysis_table$group_id]

      analysis_table <- cbind(results_titles[!names(results_titles) %in% c("group_list", "measure_list", "analysis_list")],
            analysis_table)

    } else analysis_table <- data.frame(results_titles[!names(results_titles) %in% c("group_list", "measure_list", "analysis_list")])


    if(is.null(analysis)){
      measures_table
    } else if(is.null(measures)){
      analysis_table
    } else {
      plyr::rbind.fill(measures_table, analysis_table)
    }


  })

  final_outcome_table <- do.call(plyr::rbind.fill, all_results_list)
  final_outcome_table$nct_id <- this_nct_id

  list(
    participant_flow = flow_table,
    baseline_data = baseline_table,
    outcome_data = final_outcome_table
  )

}

## group labels are stored as key: values but only referred to in results as
## keys. This makes a lookup vector.

get_group_lookup <- function(parsed, xpath){

  group_list <- tryCatch(parsed[[xpath]], error = function(e) NULL)
  if(is.null(group_list)) return(NULL)

  group_lookup <- as.data.frame(t(XML::xmlSApply(group_list,
                                                 function(node){
                                                   c(XML::xmlAttrs(node), XML::xmlValue(XML::xmlChildren(node)$title))
                                                 })), stringsAsFactors = FALSE)

  group_look <- group_lookup[,2]
  names(group_look) <- group_lookup$group_id
  group_look

}

## simple xml tables to dataframe

xmltodf <- function(parsed_xml, xpath){

  as.data.frame(do.call(plyr::rbind.fill, lapply(parsed_xml[xpath],
                                                 function(x) as.data.frame(XML::xmlToList(x),
                                                                           stringsAsFactors = FALSE))),
                stringsAsFactors = FALSE)

}