The aim of this study is to assess whether a multidomain, multidisciplinary intervention (MDI), enhanced by technological solutions, effectively improves the functional and cognitive status of older hospitalized patients at risk of disability or worsening frailty. Additionally, the study will evaluate the feasibility and acceptability of delivering these interventions remotely via technology after hospital discharge.

Participants will:

• Receive an MDI during their hospital stay and continue with remote at-home support for 3 months, or receive usual care.
• Attend outpatient clinics for follow-up assessment at 3 and 6 months.

The "Optimizing Prevention of Hospital-Acquired Disability Through Integrated Multidomain Interventions (OPTIMAge-IT)" study will evaluate impact of a MDI multidisciplinary approach, enhanced by technological solutions, on the functional and cognitive status of older hospitalized patients at risk of disability or worsening frailty.

Additionally, the study will evaluate the feasibility and acceptability of delivering MDIs remotely via technology after hospital discharge. Using a parallel cluster-randomized design, approximately 300 patients will be recruited from eight Acute Geriatric Units (AGUs) located in eight acute hospitals evenly distributed across Northern, Central, and Southern Italy.

Eligible patients will be aged 70 years or older, with mild to moderate frailty, capable of ambulation with or without assistance and able to communicate and collaborate with the research team. Participants will use smart technologies, such as smartwatches, and tablets, for guided physical activity and remote monitoring. A multidisciplinary team -including a geriatrician, a nurse, a physiotherapist, a clinical nutrition expert, a neuropsychologist and a digital coach- will assist patients in the intervention group, supervising the MDI approach during hospitalization and at the 3-month follow-up. Blood-based biomarkers and fecal samples for gut microbiome analysis will be collected for patients in the intervention group, to support frailty stratification at baseline and help define the trajectories of functional and cognitive changes from baseline to follow-up assessments.

After discharge, patients in the intervention group will continue MDI at home for 12 weeks, with follow-up visits at 3 and 6 months. The control group will receive a follow-up visit at 6 months.

Inclusion Criteria:

• Age >70 years;
• Mild to moderate frailty, defined by a panel of tools agreed upon by the group of researchers involved in the study (Primary Care Frailty Index [PC-FI] between 0.07 and 0.21, Clinical Frailty Scale [CFS] 4-6);
• Ability to walk with or without assistance
• Ability to communicate and cooperate with the research team;
• Ability to sign informed consent.

Exclusion Criteria:

• Expected hospital stay duration <3 days;
• Estimated prognosis quoad vitam <12 months;
• Persistent clinical instability, indicated by a NEWS2 score >5 (assessed within 48 hours of admission) and/or the presence of delirium (4AT >4);
• History of schizophrenia, major depression, bipolar disorder, or psychosis;
• Severe sensory deficits (visual and auditory);
• Presence of a nasogastric tube or percutaneous endoscopic gastrostomy (PEG);
• Severe cardiac conduction disorder (e.g., third-degree atrioventricular block), uncontrolled arrhythmia, new Q wave in the past six months, or ST segment depression (>3 mm) on the electrocardiogram;
• Terminal stage oncological or organic disease (e.g., Child-Pugh C cirrhosis, stage V renal disease, GOLD stage D chronic obstructive pulmonary disease, end-stage heart failure);
• Residence in a nursing home before hospital admission;
• Presence of dissected aortic aneurysm, severe aortic stenosis, acute endocarditis/pericarditis, acute thromboembolism, uncontrolled hypertension (>180/100 mmHg) or postural hypotension, uncontrolled hypoglycemia, recent fracture within the last month, or any other medical condition that hinders the execution of physical activity according to clinical judgment;
• Any condition that prevents safe participation in the intervention and/or cooperation with the study;
• Concurrent participation in other clinical studies;
• Clinical conditions or situations significantly different from the condition under study, which in the investigator's opinion could interfere with the study or prevent optimal participation;
• Participants refusal to participate in the study.