Table 1. Eligibility criteria for study samples.

	Inclusion criteria	Exclusion criteria
Objective 1a
All visitors	• all individuals who visit/contact/have a home-based appointment with the IAC
Objective 1b
Older adults–IAC health record review (n = 18)	• consenting German- or English-speaking older adults aged 64+ who live at home or are staying temporarily in a nursing home • had a visit at the IAC or at their home • had an IAC health record created	• individuals who are residing in a nursing home or are receiving end-of-life care
Older adult–interviewees (n = 8–12)	• individuals with a frailty screening score (using the Groningen Frailty Indicator [GFI]) of ≥4 • receive a Comprehensive Geriatric Assessment (CGA) by the IAC staff • aged 75+ and consent (or by proxy)	• individuals participating in another study with health-related interventions within the 30 days preceding or during the present study
Informal caregivers (n = 8–12)	• a participating older adult who was invited for an interview agrees they can be contacted • attendance at the IAC appointment with the older adult	• the older adult did not allow their study invitation • no attendance at the IAC appointment
IAC staff (n = 2)	• IAC nurse (i.e., a geriatric nurse expert) and IAC social worker	• IAC administrative support and IAC manager
External collaborators (n = 18)	• health or social care providers (e.g., GPs, home care nurses) who according to the IAC health record have worked together with the IAC staff in coordinating care for a participating older adult	• providers who have not contributed to the coordination of care with the IAC staff