# Using CDM attributes

## Set up

Let’s again load required packages and connect to our Eunomia dataset in duckdb.

    library(CDMConnector)
    library(omopgenerics)
    library(dplyr)

    write_schema <- "main"
    cdm_schema <- "main"

    con <- DBI::dbConnect(duckdb::duckdb(),
                          dbdir = eunomiaDir())
    cdm <- cdmFromCon(con,
                        cdmName = "eunomia",
                        cdmSchema = cdm_schema,
                        writeSchema = write_schema,
                        cdmVersion = "5.3")

## CDM reference attributes

Our cdm reference has various attributes associated with it. These can be useful both when programming and when developing analytic packages on top of CDMConnector.

### CDM name

It’s a requirement that every cdm reference has name associated with it. This is particularly useful for network studies so that we can associate results with a particular cdm. We can use `cdmName` (or it’s snake case equivalent `cdm_name`) to get the cdm name.

    cdmName(cdm)
    #> [1] "eunomia"

### CDM version

The OMOP CDM has various versions. We also have an attribute giving the version of the cdm we have connected to.

    cdmVersion(cdm)
    #> [1] "5.3"

### Database connection

We also have an attribute identifying the database connection underlying the cdm reference.

    cdmCon(cdm)
    #> <duckdb_connection dc950 driver=<duckdb_driver dbdir='/private/var/folders/2j/8z0yfn1j69q8sxjc7vj9yhz40000gp/T/RtmpWjkyDc/file17ed07d61c8cd.duckdb' read_only=FALSE bigint=numeric>>

This can be useful, for example, if we want to make use of DBI functions to work with the database. For example we could use `dbListTables` to list the names of remote tables accessible through the connection, `dbListFields` to list the field names of a specific remote table, and `dbGetQuery` to returns the result of a query

    DBI::dbListTables(cdmCon(cdm))
    #>  [1] "care_site"             "cdm_source"            "concept"
    #>  [4] "concept_ancestor"      "concept_class"         "concept_relationship"
    #>  [7] "concept_synonym"       "condition_era"         "condition_occurrence"
    #> [10] "cost"                  "death"                 "device_exposure"
    #> [13] "domain"                "dose_era"              "drug_era"
    #> [16] "drug_exposure"         "drug_strength"         "fact_relationship"
    #> [19] "location"              "measurement"           "metadata"
    #> [22] "note"                  "note_nlp"              "observation"
    #> [25] "observation_period"    "payer_plan_period"     "person"
    #> [28] "procedure_occurrence"  "provider"              "relationship"
    #> [31] "source_to_concept_map" "specimen"              "visit_detail"
    #> [34] "visit_occurrence"      "vocabulary"
    DBI::dbListFields(cdmCon(cdm), "person")
    #>  [1] "person_id"                   "gender_concept_id"
    #>  [3] "year_of_birth"               "month_of_birth"
    #>  [5] "day_of_birth"                "birth_datetime"
    #>  [7] "race_concept_id"             "ethnicity_concept_id"
    #>  [9] "location_id"                 "provider_id"
    #> [11] "care_site_id"                "person_source_value"
    #> [13] "gender_source_value"         "gender_source_concept_id"
    #> [15] "race_source_value"           "race_source_concept_id"
    #> [17] "ethnicity_source_value"      "ethnicity_source_concept_id"
    DBI::dbGetQuery(cdmCon(cdm), "SELECT * FROM person LIMIT 5")
    #>   person_id gender_concept_id year_of_birth month_of_birth day_of_birth
    #> 1         6              8532          1963             12           31
    #> 2       123              8507          1950              4           12
    #> 3       129              8507          1974             10            7
    #> 4        16              8532          1971             10           13
    #> 5        65              8532          1967              3           31
    #>   birth_datetime race_concept_id ethnicity_concept_id location_id provider_id
    #> 1     1963-12-31            8516                    0          NA          NA
    #> 2     1950-04-12            8527                    0          NA          NA
    #> 3     1974-10-07            8527                    0          NA          NA
    #> 4     1971-10-13            8527                    0          NA          NA
    #> 5     1967-03-31            8516                    0          NA          NA
    #>   care_site_id                  person_source_value gender_source_value
    #> 1           NA 001f4a87-70d0-435c-a4b9-1425f6928d33                   F
    #> 2           NA 052d9254-80e8-428f-b8b6-69518b0ef3f3                   M
    #> 3           NA 054d32d5-904f-4df4-846b-8c08d165b4e9                   M
    #> 4           NA 00444703-f2c9-45c9-a247-f6317a43a929                   F
    #> 5           NA 02a3dad9-f9d5-42fb-8074-c16d45b4f5c8                   F
    #>   gender_source_concept_id race_source_value race_source_concept_id
    #> 1                        0             black                      0
    #> 2                        0             white                      0
    #> 3                        0             white                      0
    #> 4                        0             white                      0
    #> 5                        0             black                      0
    #>   ethnicity_source_value ethnicity_source_concept_id
    #> 1            west_indian                           0
    #> 2                italian                           0
    #> 3                 polish                           0
    #> 4               american                           0
    #> 5              dominican                           0

## Cohort attributes

### Generated cohort set

When we generate a cohort in addition to the cohort table itself we also have various attributes that can be useful for subsequent analysis.

Here we create a cohort table with a single cohort.

    cdm <- generateConceptCohortSet(cdm = cdm,
                                    conceptSet = list("gi_bleed" = 192671,
                                                      "celecoxib" = 1118084),
                                    name = "study_cohorts",
                                    overwrite = TRUE)

    cdm$study_cohorts %>%
      glimpse()

We have a cohort set attribute that gives details on the settings associated with the cohorts (along with utility functions to make it easier to access this attribute).

    settings(cdm$study_cohorts)

We have a cohort_count attribute with counts for each of the cohorts.

    cohortCount(cdm$study_cohorts)

And we also have an attribute, cohort attrition, with a summary of attrition when creating the cohorts.

    attrition(cdm$study_cohorts)

### Creating a bespoke cohort

Say we create a custom GI bleed cohort with the standard cohort structure

    cdm$gi_bleed <- cdm$condition_occurrence %>%
      filter(condition_concept_id == 192671) %>%
      mutate(cohort_definition_id = 1) %>%
      select(
        cohort_definition_id,
        subject_id = person_id,
        cohort_start_date = condition_start_date,
        cohort_end_date = condition_start_date
      ) %>%
      compute(name = "gi_bleed", temporary = FALSE, overwrite = TRUE)

    cdm$gi_bleed %>%
      glimpse()
    #> Rows: ??
    #> Columns: 4
    #> Database: DuckDB 1.4.4 [root@Darwin 25.3.0:R 4.5.1//private/var/folders/2j/8z0yfn1j69q8sxjc7vj9yhz40000gp/T/RtmpWjkyDc/file17ed07d61c8cd.duckdb]
    #> $ cohort_definition_id <dbl> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1…
    #> $ subject_id           <int> 273, 61, 351, 579, 549, 116, 163, 304, 326, 285, …
    #> $ cohort_start_date    <date> 2011-10-10, 2005-09-15, 2018-06-28, 1999-11-06, …
    #> $ cohort_end_date      <date> 2011-10-10, 2005-09-15, 2018-06-28, 1999-11-06, …

We can add the required attributes using the `newCohortTable` function. The minimum requirement for this is that we also define the cohort set to associate with our set of custom cohorts.

    GI_bleed_cohort_ref <- tibble(cohort_definition_id = 1, cohort_name = "custom_gi_bleed")

    cdm$gi_bleed <- omopgenerics::newCohortTable(
      table = cdm$gi_bleed, cohortSetRef = GI_bleed_cohort_ref
    )

Now our custom cohort GI_bleed has the same attributes associated with it as if it had been created by `generateConceptCohortSet`. This will allow it to be used by analytic packages designed to work with cdm cohorts.

    settings(cdm$gi_bleed)
    #> # A tibble: 1 × 2
    #>   cohort_definition_id cohort_name
    #>                  <dbl> <chr>
    #> 1                    1 custom_gi_bleed
    cohortCount(cdm$gi_bleed)
    #> # A tibble: 1 × 3
    #>   cohort_definition_id number_records number_subjects
    #>                  <int>          <int>           <int>
    #> 1                    1            479             479
    attrition(cdm$gi_bleed)
    #> # A tibble: 1 × 7
    #>   cohort_definition_id number_records number_subjects reason_id reason
    #>                  <int>          <int>           <int>     <int> <chr>
    #> 1                    1            479             479         1 Initial qualify…
    #> # ℹ 2 more variables: excluded_records <int>, excluded_subjects <int>