Create a time-since-event feature specification

Produces a feature spec that computes the elapsed time between the most recent matching event and a reference date. The result is expressed in the specified unit (days or months). Useful for calculating recency of diagnoses, procedures, or measurements.

Usage

omop.feature.time_since(
  concept_set,
  reference_date = NULL,
  unit = "day",
  name = NULL
)

Arguments

concept_set

Numeric vector of concept IDs, or an omop_concept_set object defining the concepts to match.

reference_date

Character/Date; fixed ISO 8601 date used as the reference point. It is required: cohort-index recency is episode-specific and is not supported by the person-level feature reducer.

unit

Character; time unit for the result. One of "day" or "month"; months mean complete calendar months rather than fixed 30-day intervals.

name

Character; optional custom name for the feature column. If NULL, auto-generated from the concept and table context.

Value

An omop_feature_spec object with type = "time_since".

See also

ds.omop.plan.features, omop.feature.boolean, omop.feature.count

Examples

if (FALSE) { # \dontrun{
spec <- omop.feature.time_since(c(201826),
  reference_date = "2024-01-01", unit = "day")
plan <- ds.omop.plan.features(plan, "recency",
  "condition_occurrence",
  specs = list(days_since_diabetes = spec))
} # }