TABLE 3.

Extracted definition of caregivers and instructions given to proxy raters for the 6 selected studies

Study authors/year	N	Definition of proxy	Instructions for proxy raters
Moreale et al. (2017)	46	“provided care at home for physical, emotional and social needs”	“…collected from the caregivers by asking them to describe their relative’s depression state (e.g. “Do you think that your relative doesn’t feel sad, or feels sad, or feels sad all the time …”), coping strategies (e.g. “Do you think that your relative tries to look at the problem objectively and see all sides?”) and anxiety (e.g. “Do you think that he/she feels nervous and restless?).”
Rooney et al. (2013)	41	Co-habiting partner	“…their proxy also completed it ‘‘for the patient’’, based on their observations at home.”
Milbury K. et al. (2019)	20	Family caregiver (eg, spouse, sibling, adult child)	“Caregivers completed the MDASI-BT as they perceived patients’ symptom severity and interference.”
Armstrong et al. (2012)	115	Caregiver “who are primarily involved in their care in the home setting (biological, legal, or functional relationship)”	MD Anderson Symptom Inventory-Brain Tumor (MDASI-BT; completed by caregiver on behalf of patient) Prompt for answering questions adapted from Lobchuk et al.15
Brown et al. (2008)	118	Patient-identified caregiver	Unclear whether it was on behalf of the patient
Jacobs et al. (2014)	45	Patient identified nonprofessional caregiver (spouse, family member, or friend)	“…caregivers were asked to complete the same questionnaire as they perceived the patient would answer the questions. Caregivers could not fill out the questionnaire for patients.”