Purpose: To examine the impact of changes in an older person's frailty on the care-related quality of life of their informal caregiver.; Methods: Five research projects in the TOPICS-MDS database with data of both older person and informal caregiver at baseline and after 12 months follow-up were selected. Frailty was measured in five health domains (functional limitations, psychological well-being, social functioning, health-related quality of life, self-rated health).