# Step 4: Obtain aggregated data on temporal symmetry

# Introduction

In this vignette we will explore the functionality and arguments of `summariseTemporalSymmetry()` function. This function uses `cdm$intersect` introduced in the previous vignette Step 1. Generate a sequence cohort to produce aggregated statistics containing the frequency for different time gaps between the initiation of the marker and the initiation of the index (`marker_date` \(-\) `index_date`). The work of this function is best illustrated via an example.

Recall that in the previous vignette, we’ve used `cdm$aspirin` and `cdm$acetaminophen` to generate `cdm$intersect` like so:

    # Generate a sequence cohort
    cdm <- generateSequenceCohortSet(
      cdm = cdm,
      indexTable = "aspirin",
      markerTable = "acetaminophen",
      name = "intersect",
      combinationWindow = c(0,Inf))

# Obtaining temporal symmetry

    summariseTemporalSymmetry(cohort = cdm$intersect) |>
      dplyr::glimpse()
    #> Rows: 558
    #> Columns: 13
    #> $ result_id        <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,…
    #> $ cdm_name         <chr> "Synthea synthetic health database", "Synthea synthet…
    #> $ group_name       <chr> "index_name &&& marker_name", "index_name &&& marker_…
    #> $ group_level      <chr> "1191_aspirin &&& 161_acetaminophen", "1191_aspirin &…
    #> $ strata_name      <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ strata_level     <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ variable_name    <chr> "temporal_symmetry", "temporal_symmetry", "temporal_s…
    #> $ variable_level   <chr> "-29", "40", "10", "20", "69", "-35", "89", "36", "10…
    #> $ estimate_name    <chr> "count", "count", "count", "count", "count", "count",…
    #> $ estimate_type    <chr> "integer", "integer", "integer", "integer", "integer"…
    #> $ estimate_value   <chr> "6", "7", "6", "10", "5", "5", "5", "5", "-", "9", "9…
    #> $ additional_name  <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ additional_level <chr> "overall", "overall", "overall", "overall", "overall"…

The default unit of the difference of two initiations is measured in months. In this example, the first row is showing there are \(6\) cases of index happening after marker with the gap being \(29\) months whereas the second row is showing there are \(7\) cases of index happening before marker with the gap being \(40\) months.

## Modify the cohort based on `cohort_definition_id`

This parameter is used to subset the cohort table inputted to the `summariseTemporalSymmetry()`. Imagine the user only wants to include `cohort_definition_id` \(= 1\) from `cdm$intersect` in the `summariseTemporalSymmetry()`, then one could do the following:

    summariseTemporalSymmetry(cohort = cdm$intersect,
                              cohortId = 1) |>
      dplyr::glimpse()
    #> Rows: 558
    #> Columns: 13
    #> $ result_id        <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,…
    #> $ cdm_name         <chr> "Synthea synthetic health database", "Synthea synthet…
    #> $ group_name       <chr> "index_name &&& marker_name", "index_name &&& marker_…
    #> $ group_level      <chr> "1191_aspirin &&& 161_acetaminophen", "1191_aspirin &…
    #> $ strata_name      <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ strata_level     <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ variable_name    <chr> "temporal_symmetry", "temporal_symmetry", "temporal_s…
    #> $ variable_level   <chr> "144", "31", "130", "58", "-363", "291", "71", "-21",…
    #> $ estimate_name    <chr> "count", "count", "count", "count", "count", "count",…
    #> $ estimate_type    <chr> "integer", "integer", "integer", "integer", "integer"…
    #> $ estimate_value   <chr> "-", "11", "5", "5", "-", "-", "5", "9", "-", "8", "-…
    #> $ additional_name  <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ additional_level <chr> "overall", "overall", "overall", "overall", "overall"…

Of course and once again this does nothing because every entry in `cdm$intersect` has `cohort_definition_id` \(= 1\).

## Modify `timescale`

Recall the default for the timescale is `month`, one could also change this to either `day` or `year`.

    summariseTemporalSymmetry(cohort = cdm$intersect,
                              timescale = "day") |>
      dplyr::glimpse()
    #> Rows: 1,350
    #> Columns: 13
    #> $ result_id        <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,…
    #> $ cdm_name         <chr> "Synthea synthetic health database", "Synthea synthet…
    #> $ group_name       <chr> "index_name &&& marker_name", "index_name &&& marker_…
    #> $ group_level      <chr> "1191_aspirin &&& 161_acetaminophen", "1191_aspirin &…
    #> $ strata_name      <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ strata_level     <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ variable_name    <chr> "temporal_symmetry", "temporal_symmetry", "temporal_s…
    #> $ variable_level   <chr> "-12000", "661", "-630", "151", "750", "4891", "-5038…
    #> $ estimate_name    <chr> "count", "count", "count", "count", "count", "count",…
    #> $ estimate_type    <chr> "integer", "integer", "integer", "integer", "integer"…
    #> $ estimate_value   <chr> "-", "5", "-", "-", "-", "-", "-", "-", "-", "-", "-"…
    #> $ additional_name  <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ additional_level <chr> "overall", "overall", "overall", "overall", "overall"…

    summariseTemporalSymmetry(cohort = cdm$intersect,
                              timescale = "year") |>
      dplyr::glimpse()
    #> Rows: 94
    #> Columns: 13
    #> $ result_id        <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,…
    #> $ cdm_name         <chr> "Synthea synthetic health database", "Synthea synthet…
    #> $ group_name       <chr> "index_name &&& marker_name", "index_name &&& marker_…
    #> $ group_level      <chr> "1191_aspirin &&& 161_acetaminophen", "1191_aspirin &…
    #> $ strata_name      <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ strata_level     <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ variable_name    <chr> "temporal_symmetry", "temporal_symmetry", "temporal_s…
    #> $ variable_level   <chr> "-33", "12", "6", "-4", "10", "0", "-7", "13", "20", …
    #> $ estimate_name    <chr> "count", "count", "count", "count", "count", "count",…
    #> $ estimate_type    <chr> "integer", "integer", "integer", "integer", "integer"…
    #> $ estimate_value   <chr> "-", "39", "55", "68", "39", "111", "24", "24", "15",…
    #> $ additional_name  <chr> "overall", "overall", "overall", "overall", "overall"…
    #> $ additional_level <chr> "overall", "overall", "overall", "overall", "overall"…

    CDMConnector::cdmDisconnect(cdm = cdm)