Create a study population

createStudyPopulation(cohortMethodData, population = NULL, outcomeId,
  firstExposureOnly = FALSE, restrictToCommonPeriod = FALSE,
  washoutPeriod = 0, removeDuplicateSubjects = FALSE,
  removeSubjectsWithPriorOutcome = TRUE, priorOutcomeLookback = 99999,
  minDaysAtRisk = 1, riskWindowStart = 0,
  addExposureDaysToStart = NULL, startAnchor = "cohort start",
  riskWindowEnd = 0, addExposureDaysToEnd = NULL,
  endAnchor = "cohort end", censorAtNewRiskWindow = FALSE)

Arguments

cohortMethodData

An object of type cohortMethodData as generated using getDbCohortMethodData.

population

If specified, this population will be used as the starting point instead of the cohorts in the cohortMethodData object.

outcomeId

The ID of the outcome. If not specified, no outcome-specific transformations will be performed.

firstExposureOnly

Should only the first exposure per subject be included? Note that this is typically done in the createStudyPopulation function,

restrictToCommonPeriod

Restrict the analysis to the period when both exposures are observed?

washoutPeriod

The mininum required continuous observation time prior to index date for a person to be included in the cohort.

removeDuplicateSubjects

Remove subjects that are in both the target and comparator cohort? See details for allowed values.

removeSubjectsWithPriorOutcome

Remove subjects that have the outcome prior to the risk window start?

priorOutcomeLookback

How many days should we look back when identifying prior outcomes?

minDaysAtRisk

The minimum required number of days at risk.

riskWindowStart

The start of the risk window (in days) relative to the startAnchor.

addExposureDaysToStart

DEPRECATED: Add the length of exposure the start of the risk window? Use startAnchor instead.

startAnchor

The anchor point for the start of the risk window. Can be "cohort start" or "cohort end".

riskWindowEnd

The end of the risk window (in days) relative to the endAnchor.

addExposureDaysToEnd

DEPRECATED: Add the length of exposure the risk window? Use endAnchor instead.

endAnchor

The anchor point for the end of the risk window. Can be "cohort start" or "cohort end".

censorAtNewRiskWindow

If a subject is in multiple cohorts, should time-at-risk be censored when the new time-at-risk starts to prevent overlap?

Value

A data frame specifying the study population. This data frame will have the following columns:

rowId

A unique identifier for an exposure

subjectId

The person ID of the subject

cohortStartdate

The index date

outcomeCount

The number of outcomes observed during the risk window

timeAtRisk

The number of days in the risk window

survivalTime

The number of days until either the outcome or the end of the risk window

Details

Create a study population by enforcing certain inclusion and exclusion criteria, defining a risk window, and determining which outcomes fall inside the risk window.

The removeduplicateSubjects argument can have one of the following values:

"keep all"

Do not remove subjects that appear in both target and comparator cohort

"keep first"

When a subjects appear in both target and comparator cohort, only keep whichever cohort is first in time. If both cohorts start simultaneous, the person is removed from the analysis.

"remove all"

Remove subjects that appear in both target and comparator cohort completely from the analysis."