Responding to grief-related needs in older adults: protocol for a community-based matched-care trial (GriefDiff)

Prolonged grief disorder (PGD) affects a significant proportion of bereaved people and may be especially burdensome in later life, when cumulative losses, health problems, and reduced social resources can hinder adjustment. Grief support is often reactive, and many older adults do not access timely, appropriate care. GriefDiff will study a differentiated, community-based model that matches intervention intensity and format to individual risk and relational needs. GriefDiff is a mixed-methods (QUAN→QUAL) protocol. The quantitative component is a three-arm, tiered, parallel-group superiority randomised controlled trial delivered in community settings across Portugal, in collaboration with a national grief association. Eligible participants are Portuguese adults aged ≥60 years, bereaved 1–12 months, with a significant emotional bond to the deceased. After consent, participants complete a grief-risk tool and a mutuality-based relational-needs screener. Stratified block randomisation allocates participants to Information and Grief Literacy (IGLiteracy; one group session plus bi-weekly SMS reminders), an Individual Self-Help Program (ISelfHP; older-adult web app with optional offline materials and brief telephone guidance), or Moderated Self-Help Groups (MSHGroups; manualised weekly groups). Assessments occur at baseline, 3 months (post) and 6 months (follow-up). The primary outcome is prolonged grief symptoms; secondary outcomes are depression and anxiety. Target sample is N=324 (108/arm). Analyses will follow an intention-to-treat approach and will use mixed-effects models for repeated measures with fixed-sequence gatekeeping. Qualitative focus groups will compare matched versus non-matched allocations to clarify perceived fit, identify barriers, and inform future implementation strategies for differentiated grief care. Developing scalable, differentiated community responses will help address a growing societal challenge while meeting the needs of older adults. By evaluating programme effectiveness and refining the screening procedure, this study aims to inform the development and implementation of needs-based grief care in community settings. ClinicalTrials.gov, NCT07433101; registered on 2026-02-25.