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Constraints are used to narrow down the search criteria to a particular time frame, number of occurrences or a specific value or range of values. In i2b2, there are several types of constraints that can be defined in the Query Tool view.  These include Date Constraints, Occurrence Constraints and Time Exclusion, Occurrence, Panel, Temporal, Time and Value Constraints.

Containers

A Container is a . . .

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An encounter set contains a list of specific patients that you identify. A list of patients can be added to an Encounter Set from the Workspace view. These can be moved to the Query Tool view by simply dragging the encounter set from either the Previous Query view or the Workplace view. These can be used in a query by dragging the patient set from Previous Query and Workplace views. When you run the query it will use the encounter set to query against.

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ExclusionConstraintGlossary ExclusionConstraintGlossary

Exclusion Constraints

Constraint will not include patients with the concepts listed in the panel.

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The Navigate Terms view contains a hierarchical display of all the items that can be used to search the database.

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OccurenceConstraintGlossary OccurenceConstraintGlossary

Occurrence Constraints

Constraint is by the number of occurrences an item is documented.

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The query tool knows which operator to use based on the panels used when defining the query. It is important to verify you are setting up your query correctly as each operator will return different results.

AND Operator

The AND operator returns a record if both the first condition and the second conditions are true. The query tool uses the AND operator when concepts are listed in different panels.

Example:

WHAT: Return only those patients who have Acute Myocardial Infarction AND Angina Pectoris.

HOW: In the query tool add the concept Acute Myocardial Infarction to Group 1 and then add the concept Angina Pectoris to Group 2.

RESULT: The population is limited by requiring the patients fulfill both requirements.

OR Operator

The OR operator returns a record if either the first condition or the second conditions are true. The query tool uses the OR operator when concepts are listed in different panels.

Example:

WHAT: Return only those patients who have Acute Myocardial Infarction OR Angina Pectoris.

HOW: In the query tool add both concepts Acute Myocardial Infarction and Angina Pectoris to Group 1.

RESULT: The population is broadened to include all patients who fit either one of those criteria.

Panels

Panels are sections on the Main Screen that identify particular functionality.  These include the Find Terms Panel, Query Panel, Workspace Panel, etc.

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PanelConstraintGlossary PanelConstraintGlossary

Panel Timing

Constraint is defined on the panel level and utilizes the patient encounters and / or instance number when determining eligibility

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Both temporal and panel constraints are very similar in that both utilize the visit / encounter information along with the concepts defined to determine if a patient meets the search criteria. The main difference between a temporal and a panel timing constraint is that temporal constraints are defined at the query level and panel timing constraints are defined at the panel level.

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TemporalConstraintGlossary TemporalConstraintGlossary

Temporal Constraint

As stated in the previous section the Temporal Constraint is defined at the query level. There are three available options:

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RESULTS: there are 47 patients who have had a medication with a dose of 500 mg and a frequency of once a day entered as a fact in the observation_fact table, where medication dose and frequency have the same patient_num.

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ValueConstraintGlossary ValueConstraintGlossary

Value Constraints

Constraint is by the value associated to a concept or modifier. Not all items have values

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