Background: Frailty confers greater risks of negative health outcomes in hospitalised older adults. To improve care for this vulnerable population, Comprehensive Geriatric Assessment (CGA) is recommended for frail older persons. However, implementing CGA outside of specialised geriatrician-led settings is limited, and few care models use frailty to identify and target older persons for CGA in the hospital-wide context. The Inpatient Nursing Frailty Assessment (INFA) programme is a CGA-based care model that targets frail older adults acutely admitted to the hospital under non-geriatrician care. The INFA collects information from routine admission assessments by ward nurses, identifying CGA domains of functional decline, delirium, falls, sensory impairment, nutrition, oral health, and swallowing. The CGA allows earlier identification of health issues and development of a personalised care plan, which directs patients to resources that mitigate the risks of functional decline. Resources include nurse-initiated interventions, multidisciplinary team care, discharge planning, community care referrals, and specialist geriatric medicine reviews.

Methods: The investigators aim to evaluate the INFA programme over two phases: pre-implementation and implementation. The updated CFIR including its Outcomes Addendum is the framework guiding both phases in the evaluation of effectiveness and implementation. The investigator's hybrid type 2 effectiveness-implementation study design is anchored in this framework. During pre-implementation, the investigators will evaluate the determinants of implementation success and subsequently refine implementation strategies. In the implementation phase, the investigators apply a quasi-experimental approach with intervention and control groups to examine the effects of the INFA intervention compared to usual care. Study participants are patients admitted to medical and surgical wards and are not receiving geriatric care. Individuals are aged 65 years and above and mild to moderately frail (CFS score 4-6). Implementation research in this phase aims to evaluate implementation outcomes. The primary outcome is activities of daily living at six months post-discharge. Secondary outcomes include length of stay, healthcare utilisation including readmissions and ED visits, quality-of-life, and cost-effectiveness. Discussion: The study's overall goal is to enhance the quality of care for frail older adults during their hospital stay, leading to improved functional outcomes.