OMOP/Documentation/CommonDataModel_Wiki_Files/StandardizedClinicalDataTables/PROCEDURE_OCCURRENCE.md

The PROCEDURE_OCCURRENCE table contains records of activities or processes ordered by, or carried out by, a healthcare provider on the patient to have a diagnostic or therapeutic purpose. Procedures are present in various data sources in different forms with varying levels of standardization. For example:

• Medical Claims include procedure codes that are submitted as part of a claim for health services rendered, including procedures performed.
• Electronic Health Records that capture procedures as orders.

Field	Required	Type	Description
procedure_occurrence_id	Yes	integer	A system-generated unique identifier for each Procedure Occurrence.
person_id	Yes	integer	A foreign key identifier to the Person who is subjected to the Procedure. The demographic details of that Person are stored in the PERSON table.
procedure_concept_id	Yes	integer	A foreign key that refers to a standard procedure Concept identifier in the Standardized Vocabularies.
procedure_date	No	date	The date on which the Procedure was performed.
procedure_datetime	Yes	datetime	The date and time on which the Procedure was performed.
procedure_type_concept_id	Yes	integer	A foreign key to the predefined Concept identifier in the Standardized Vocabularies reflecting the type of source data from which the procedure record is derived, belonging to the 'Procedure Type' vocabulary.
modifier_concept_id	Yes	integer	A foreign key to a Standard Concept identifier for a modifier to the Procedure (e.g. bilateral). These concepts are typically distinguished by 'Modifier' concept classes (e.g., 'CPT4 Modifier' as part of the 'CPT4' vocabulary).
quantity	No	integer	The quantity of procedures ordered or administered.
provider_id	No	integer	A foreign key to the provider in the PROVIDER table who was responsible for carrying out the procedure.
visit_occurrence_id	No	integer	A foreign key to the Visit in the VISIT_OCCURRENCE table during which the Procedure was carried out.
visit_detail_id	No	integer	A foreign key to the Visit Detail in the VISIT_DETAIL table during which the Procedure was carried out.
procedure_source_value	No	varchar(50)	The source code for the Procedure as it appears in the source data. This code is mapped to a standard procedure Concept in the Standardized Vocabularies and the original code is, stored here for reference. Procedure source codes are typically ICD-9-Proc, CPT-4, HCPCS or OPCS-4 codes.
procedure_source_concept_id	Yes	integer	A foreign key to a Procedure Concept that refers to the code used in the source.
modifier_source_value	No	varchar(50)	The source code for the qualifier as it appears in the source data.

Conventions

No.	Convention Description
1	Valid Procedure Concepts belong to the 'Procedure' domain. Procedure Concepts are based on a variety of vocabularies: SNOMED-CT, ICD-9-Proc, CPT-4, HCPCS and OPCS-4, but also atypical Vocabularies such as ICD-9-CM or MedDRA.
2	Procedures are expected to be carried out within one day and therefore have no end date.
3	Procedures could involve the application of a drug, in which case the procedural component is recorded in the procedure table and simultaneously the administered drug in the drug exposure table when both the procedural component and drug are identifiable.
4	If the quantity value is omitted, a single procedure is assumed.
5	The Procedure Type defines from where the Procedure Occurrence is drawn or inferred. For administrative claims records the type indicates whether a Procedure was primary or secondary and their relative positioning within a claim.
6	The Visit during which the procedure was performed is recorded through a reference to the VISIT_OCCURRENCE table. This information is not always available.
7	The Visit Detail during with the procedure was performed is recorded through a reference to the VISIT_DETAIL table. This information is not always available.
8	The Provider carrying out the procedure is recorded through a reference to the PROVIDER table. This information is not always available.
9	When dealing with duplicate records, the ETL must determine whether to sum them up into one record or keep them separate. Things to consider are: Same Procedure Same PROCEDURE_DATETIME Same Visit Occurrence or Visit Detail Same Provider Same Modifier for Procedures Same COST_ID THEMIS issue #27
10	If a Procedure has a quantity of '0' in the source, this should default to '1' in the ETL. If there is a record in the source it can be assumed the exposure occurred at least once (THEMIS issue #26).