Visit Occurrence

The VISIT_OCCURRENCE table contains the spans of time describing a Person’s individual episodes of care. They start with a presentation or admission (depending on their route) and end with the matched discharge.

Field	Required	Type	FK Table	Description
visit_occurrence_id	Yes	bigint		A unique identifier for each Person’s visit or encounter at a healthcare provider.
person_id	Yes	bigint	PERSON	A foreign key identifier to the Person for whom the visit is recorded.
visit_concept_id	Yes	bigint	CONCEPT	A foreign key that refers to a visit Concept identifier in the Standardized Vocabularies. See mappings below.
visit_start_date	Yes	date		The UTC start date of the visit.
visit_start_datetime	No	datetime		The UTC date and time of the admission. This should be the earliest presentation time at the hospital (potentially before getting assigned a bed), since all observations should be bounded by the start and end datetime.
visit_end_date	No	date		The UTC end date of the visit. NULL means the patient has not been discharged.
visit_end_datetime	No	datetime		The UTC date and time of the visit end. NULL means the patient has not been discharged.
visit_type_concept_id	No	bigint	CONCEPT	Not used.
provider_id	No	bigint	PROVIDER	Not used.
care_site_id	Yes	bigint	CARE_SITE	The trust or hospital the admission was at.
visit_source_value	No	varchar(50)		Visit / episode / contact identifier in the local site system.
visit_source_concept_id	No	bigint	CONCEPT	If the visit source value is coded in the source data using an OMOP supported vocabulary put the concept id representing the source value here.
admitting_source_value	No	varchar(50)		Raw EHR value for admitting source.
admitting_source_concept_id	No	bigint	CONCEPT	A foreign key to the predefined concept in the Place of Service Vocabulary reflecting the admitting source for a visit. Same possible values as discharge_to_concept_id .
discharge_to_source_value	No	varchar(50)		Raw EHR value for discharge to.
discharge_to_concept_id	No	bigint	CONCEPT	A foreign key to the predefined concept in the Place of Service Vocabulary reflecting the discharge disposition for a visit. See table below. Where a visit_end_datetime exists, NULL means that they left to an unknown location alive.
preceding_visit_occurrence_id	No	bigint	VISIT_OCCURRENCE	A foreign key to the Visit Occurrence record of the visit immediately preceding this visit.

Conventions

• A Visit Occurrence is recorded for each visit to a healthcare facility.
• Valid Visit Concepts belong to the “Visit” domain. The most common HIC used ones are listed below.
• Handling of death: in the case when a patient died during admission, e.g., discharge_to_concept_id = 4216643|Patient died .
• Source Concepts from place of service vocabularies are mapped into these standard Visit Concepts in the Standardized Vocabularies.
• At any one day, there could be more than one visit.
• preceding_visit_id can be used to link a visit immediately preceding the current visit.
• A transfer between two hospitals within the same trust should create a new Visit Occurrence where possible.

Standard Mappings

Field visit_concept_id

Code	Name
262	Emergency Room and Inpatient Visit
9203	Emergency Room Visit
9201	Inpatient Visit
9202	Outpatient Visit

Field admitting_source_concept_id

These destinations have been chosen as they are mappings to the NHS data dictionary, which is the likely format that trusts store admission information.

Code	Name
8536	Home
38003619	Prison/Correctional Facility
8971	Inpatient Psychiatric Facility
8717	Inpatient Hospital
8882	Adult Living Care Facility
8615	Assisted Living Facility
45769929	Born in hospital
8546	Hospice

Field discharge_to_concept_id

These destinations have been chosen as they are mappings to the NHS data dictionary, which is the likely format that trusts store discharge information.

Code	Name
8536	Home
38003619	Prison/Correctional Facility
8971	Inpatient Psychiatric Facility
8717	Inpatient Hospital
8882	Adult Living Care Facility
8615	Assisted Living Facility
4216643	Patient died
8951	Intermediate Mental Care Facility
8546	Hospice
NULL	Patient discharged alive to an unknown location

Relationship to VISIT_DETAIL