The impacts and effectiveness of support for people bereaved through advanced illness: A systematic review and thematic synthesis.

Background: Bereavement support is a key component of palliative care, with different types of support recommended according to need. Previous reviews have typically focused on specialised interventions and have not considered more generic forms of support, drawing on different research methodologies.

Aim: To review the quantitative and qualitative evidence on the effectiveness and impact of interventions and services providing support for adults bereaved through advanced illness.

Design: A mixed-methods systematic review was conducted, with narrative synthesis of quantitative results and thematic synthesis of qualitative results. The review protocol is published in PROSPERO ( www.crd.york.ac.uk/prospero , CRD42016043530).

Data Sources: The databases MEDLINE, Embase, PsycINFO, CINAHL and Social Policy and Practice were searched from 1990 to March 2019. Studies were included which reported evaluation results of bereavement interventions, following screening by two independent researchers. Study quality was assessed using GATE checklists.

Results: A total of 31 studies were included, reporting on bereavement support groups, psychological and counselling interventions and a mix of other forms of support. Improvements in study outcomes were commonly reported, but the quality of the quantitative evidence was generally poor or mixed. Three main impacts were identified in the qualitative evidence, which also varied in quality: 'loss and grief resolution', 'sense of mastery and moving ahead' and 'social support'.

Conclusion: Conclusions on effectiveness are limited by small sample sizes and heterogeneity in study populations, models of care and outcomes. The qualitative evidence suggests several cross-cutting benefits and helps explain the impact mechanisms and contextual factors that are integral to the support.