Variables Dictionary

Data Dictionary

Patient Variables

Variable	Type	Description	Values
patient_id	INT	Unique identifier for each patient	Numeric, auto-incrementing
age	INT	Patient age in years at time of registration	0-120
gender	VARCHAR(1)	Patient’s biological sex at birth	‘M’ = Male, ‘F’ = Female
birth_date	DATE	Patient’s date of birth	YYYY-MM-DD format
race	VARCHAR(50)	Patient’s self-reported race/ethnicity	White, Black, Asian, Hispanic, Other
insurance	VARCHAR(50)	Primary insurance type	Medicare, Medicaid, Private, Self-pay
zip_code	VARCHAR(5)	Patient’s residential ZIP code	5-digit US postal code
marital_status	VARCHAR(20)	Patient’s marital status	Single, Married, Divorced, Widowed
language	VARCHAR(50)	Patient’s primary language	English, Spanish, Other
employment	VARCHAR(50)	Employment status	Employed, Unemployed, Retired, Student

Visit Variables

Variable	Type	Description	Values
visit_id	INT	Unique identifier for each visit	Numeric, auto-incrementing
patient_id	INT	Foreign key linking to patients table	References patient_id
visit_date	DATE	Date of healthcare encounter	YYYY-MM-DD format
visit_type	VARCHAR(50)	Category of healthcare visit	Outpatient, Emergency, Inpatient
provider_id	INT	ID of primary care provider	References providers table
facility_id	INT	Location where care was provided	References facilities table
admission_date	DATE	Start date for inpatient stays	YYYY-MM-DD format
discharge_date	DATE	End date for inpatient stays	YYYY-MM-DD format
length_of_stay	INT	Days spent in hospital	Numeric (days)
discharge_disposition	VARCHAR(50)	Discharge status/location	Home, SNF, Rehab, Expired

Diagnosis Variables

Variable	Type	Description	Values
diagnosis_id	INT	Unique identifier for diagnosis	Numeric, auto-incrementing
visit_id	INT	Foreign key linking to visits	References visit_id
icd_code	VARCHAR(10)	ICD-10 diagnosis code	Valid ICD-10 code
diagnosis_date	DATE	Date diagnosis was recorded	YYYY-MM-DD format
primary_dx	BOOLEAN	Indicates if primary diagnosis	TRUE/FALSE
chronic_flag	BOOLEAN	Indicates chronic condition	TRUE/FALSE
severity	INT	Severity score of condition	1-5 scale
onset_date	DATE	When symptoms first appeared	YYYY-MM-DD format
resolved_date	DATE	When condition resolved	YYYY-MM-DD format
notes	TEXT	Clinical notes about diagnosis	Free text

Medication Variables

Variable	Type	Description	Values
med_id	INT	Unique identifier for prescription	Numeric, auto-incrementing
patient_id	INT	Foreign key linking to patients	References patient_id
drug_name	VARCHAR(100)	Generic medication name	Standard drug names
dosage	VARCHAR(50)	Prescribed medication dose	Includes unit (mg, mcg, etc)
frequency	VARCHAR(50)	How often medication taken	QD, BID, TID, PRN, etc
start_date	DATE	When prescription started	YYYY-MM-DD format
end_date	DATE	When prescription ended	YYYY-MM-DD format
active	BOOLEAN	Current prescription status	TRUE/FALSE
prescriber_id	INT	Provider who prescribed med	References providers table
pharmacy_id	INT	Dispensing pharmacy	References pharmacies table
refills	INT	Number of refills remaining	0-99
last_filled	DATE	Date of last dispensing	YYYY-MM-DD format

Lab Results Variables

Variable	Type	Description	Values
lab_id	INT	Unique identifier for lab result	Numeric, auto-incrementing
patient_id	INT	Foreign key linking to patients	References patient_id
test_name	VARCHAR(100)	Name of laboratory test	Standard lab test names
result_value	VARCHAR(50)	Numeric or categorical result	Depends on test type
units	VARCHAR(20)	Units of measurement	mg/dL, mmol/L, etc
ref_range_low	FLOAT	Lower limit of normal range	Numeric value
ref_range_high	FLOAT	Upper limit of normal range	Numeric value
collection_date	DATE	When sample was collected	YYYY-MM-DD format
result_date	DATE	When results were available	YYYY-MM-DD format
abnormal_flag	VARCHAR(1)	Result normality indicator	‘H’=High, ‘L’=Low, ‘N’=Normal

Vital Signs Variables

Variable	Type	Description	Values
vital_id	INT	Unique identifier for vital signs	Numeric, auto-incrementing
visit_id	INT	Foreign key linking to visits	References visit_id
measure_date	DATE	When vitals were recorded	YYYY-MM-DD format
temperature	FLOAT	Body temperature	Fahrenheit
heart_rate	INT	Heart rate	Beats per minute
blood_pressure_sys	INT	Systolic blood pressure	mmHg
blood_pressure_dia	INT	Diastolic blood pressure	mmHg
respiratory_rate	INT	Breathing rate	Breaths per minute
oxygen_saturation	INT	Blood oxygen level	Percentage (0-100)
height	FLOAT	Patient height	Inches
weight	FLOAT	Patient weight	Pounds
bmi	FLOAT	Body Mass Index	Calculated from height/weight