NCT03417219.

Study characteristics
Methods	Design: Parallel randomised controlled trial. No. of participating centres: VA Palo Alto Health Care System, Palo Alto, CA, USA. Study dates: 2015 ‐2017.
Participants	Inclusion criteria: Caregivers of 18 years and older with reported distress associated to caregiving, providing at least 7 hours of care per week over the past 3 months, living with a Veteran diagnosed with dementia, and proficient in spoken and written English. Exclusion criteria: Current or lifetime history of any psychiatric disorder with psychotic features, prominent suicidal or homicidal ideation, met DSM‐IV criteria for drug or alcohol abuse or dependence (except nicotine) within the past six months, presence of alcohol intoxication or alcohol withdrawal during study recruitment or participation, diagnosis of probable or possible dementia, a Telephone Cognitive Screen score of <20, participation in another caregiver intervention study within the past year, lack of access to telephone and Internet services in the home, illness that would prevent study participation, planned transfer of care recipient to another caregiver or nursing home within 6 months, currently living with an implantable cardioverter defibrillator or pacemaker, and known pregnancy at time of consent. No. of participants randomised to intervention: ‐ Education and Skill Building Rehabilitation‐mobile (ESBR‐m, n=8). ‐ Usual care (n=8). Baseline characteristics: ‐ Caregivers: Mean age 66.06 years (SD=10.04), 13 females and 3 males ‐ Care recipients: No information provided.
Interventions	Experimental: Education and skill building rehabilitation‐mobile (ESBR‐m). Control: Usual care plus supplemental educational materials. Length of intervention: 3 months.
Outcomes	Primary outcomes: ‐ Caregiver burden: 22‐item Zarit Burden Interview (ZBI). ‐ Depressive symptoms: 20‐item Center for Epidemiological Studies‐Depression (CES‐D). ‐ Stress: 14‐item Terceived Stress Scale (PSS). Secondary outcomes: ‐ None stated. Outcomes assessment: At 4 months.
Notes	Clinical trial registration code: NCT03417219. Funding: VA office of Research and Development. Conflicts of interest: None declared.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Comment: Sequential randomization procedure modified to assure comparability at baseline for dementia subtype.
Allocation concealment (selection bias)	Unclear risk	Comment: There is no information on allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: The study is presented as open label because of the impossibility to mask interventions throughout the study.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: There is no information on blinding of outcome assessors beyond baseline, however this is an unmasked study with participants not blind to interventions and subjective participant‐reported outcomes. Moreover, interventions components and procedures are not comparable.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: The study aimed to recruit 40 participants but closed with 16 (40% of sample target). Of those participants, all allocated to ESBR‐m completed the study (8/8) whereas 3 of participants allocated to usual care did not completed the study (3/8). There is no information on reasons for no completion.
Selective reporting (reporting bias)	Low risk	Comment: There is a trial registration and published protocol: All prespecified outcomes are reported.
Other bias	Low risk	Comment: None detected.