Create a followup duration variable

Produces a derived variable computing days from a reference date (default fixed reference date to observation end. When omitted, today's date is recorded in the variable specification at construction time. With multiple spells, the unique period containing the reference date is selected.

Usage

omop_variable_followup(name = "followup", reference_date = NULL)

Arguments

name

Character; output column name (default "followup").

reference_date

Date or NULL; explicit reference date.

Value

An omop_variable with format = "followup".