Twelve studies were included in the review (range 11 to 700 participants). The methodology quality of the included studies varied. The observed total internal validity score ranged from 0 to 5 out of 9. Only two out of 12 studies were considered to be of good quality. The follow-up ranged from 30 days to 12 months.
Six studies reported significant improvements in carers' well-being with Internet-based intervention for depression, sense of competence, decision-making confidence, self-efficacy, and burden. One study found increased intention to seek support, increased carer gain, and decreased carer stress and strain. One study reported increased carer self-control. In addition to online interventions, guidance from a coach (two studies) and interaction with other carers (two studies) could be beneficial.
There were no significant differences between or within treatment groups for carer quality of life, use of stress management techniques, social isolation, and health status.
Several studies reported carers' experience as additional outcomes; these included increased knowledge of the disease and caring (three studies), increased coping with caring (two studies), confidence in carer skills (three studies) and reduced feelings of isolation (one study).