Table 1.

Why are older adults living with the complexity of MLTC, frailty with a recent deterioration in health under-served by research?

Frailty	MLTC	MLTC, Frailty and Recent Deterioration in Health
Personal reasons • Lack of perceived benefit • Distrust of research staff • Lack of confidence to make a decision Health reasons • Poor health and mobility problems • Communication problems/cognitive impairment • Disability • Fatigue Research procedures • Difficult to understand and read the consent form/information leaflets • Time consuming/demanding/intrusive • Travel requirements Other • Stereotypical assumptions about ageing; viewed as vulnerable and difficult to locate	Personal reasons • Routines (i.e., caring for grandchildren) Health reasons • Complex needs; physical, psychological and social performance • Intrusive problems; pain, incontinence, falls, pressure ulcers and delirium • Fatigue, shortness of breath, limited mobility and anxiety • Medical reasons and health-related commitments (i.e., medical appointments) Research procedures • Travel and transport issues • Research outcomes less predictable and increased risk of adverse events • Time requirements	Paucity of research: one study conducted by Bone et al., successfully recruited 90 older adults with frailty and a recent deterioration in health
Strategies for increasing recruitment and retention of these under-served groups.
Recruitment	Retention	Other
• Take time to explain the research fully and use simple language, involve relatives and friends to help/support the older adult to make a decision • Short consent form using large print • Educational materials • Gifts/financial compensation/reimbursement of costs incurred • Establish a trustworthy relationship • Use General Practitioners as a credible source • Ensure communication aids are working • Use suitable facilities • Mitigate unique challenges before starting recruitment • Avoid certain times of approaching participants	• Offer a flexible approach and adaptation to study procedures including home-based assessments • Avoid the use of time-consuming questionnaires • Divide tasks into smaller sections and allow for breaks • Consider data collection and intervention delivered by telephone • Maintain regular contact with participants • Ensure research and clinical staff have excellent social skills • Provide feedback on participants performance and share study results • Consider outcome measures as physical, psychologically and socially acceptable	• Use patient and public involvement • Include carers of participants and consider carer respite • Consider tools and resources within the Innovations in Clinical Trial Design and Delivery for the Under-served framework and roadmap (INCLUDE)