Table 2.

Covariates for Objective 1 Analyses

Type of measure	Database	Data used to define
Socio-demographic variables	OPC, PTF	Age, sex, race, marital status
Clinical characteristics
Number of unique drugs	Pharmacy	VA product; total number of oral, injectable, transdermal drugs in previous year.
Physical comorbidities	OPC, PTF	Traumatic brain injury, migraine/ headache, brain tumor, dementia, cerebrovascular disease, cardiac conditions, hypertension, other neurological disorders, obesity
Mental health comorbidities	OPC, PTF	Substance use disorder, schizophrenia, depression, bipolar disorder, post-traumatic stress disorder, anxiety
Distance to Hub/ Spoke	OPC	ZIP variable

OPC: outpatient clinic; PTF: patient treatment file.