Background: Four out of ten older people having surgery live with frailty, leaving them vulnerable to adverse outcomes due to accumulation of age- and disease-related deficits. An increasing number of people with frailty require surgery. Frailty is associated with a >2-fold increase in complications and new patient-reported disability; absolute rates are >50% and 20% respectively; physical and physiologic deficits are particularly implicated. Mortality, costs and institutionalization after surgery are also significantly associated with frailty.

Despite frailty's strong association with adverse outcomes, few perioperative trials include older people with frailty. Exercise therapy may improve function and decrease complications for other people with frailty by addressing physical and physiologic deficits. However, existing trials are small (median n=54) and single center. Most interventions have been resource-intensive, requiring attendance at hospital-based sessions, which may limit access to many who could benefit. Patient-reported outcomes are also lacking. Therefore, a multicenter trial of home-based exercise therapy before surgery for older people with frailty, powered to address patient-reported outcomes, is needed. Our trial will address these knowledge gaps by testing the effectiveness of home-based preoperative exercise (exercise prehabilitation) in decreasing patient-reported disability and postoperative complications in older people with frailty having major surgery.

Research aims: Estimate the effectiveness of exercise prehabilitation on:

• Co-primary outcomes: patient-reported disability 30-days after surgery and in-hospital complications
• Secondary outcomes: patient-centered (discharge home, survival, 30, 90 and one-year disability scores, quality of life, function) and system-relevant (length of stay, admissions)
• Health economic outcomes: costs, cost-effectiveness Methods

Design, setting and participants: Parallel-arm multicenter randomized controlled trial at 14 Canadian hospitals. People => 60 years old with frailty (Clinical Frailty Scale score of 4/9) having major elective non-cardiac surgery (vascular, intrathoracic, intraabdominal, pelvic, ENT) with expected length of stay of => 2 days will be included.

Intervention: Home-based exercise program with demonstrated efficacy, feasibility and acceptability tailored for people with frailty.

Outcomes and sample size: Co-primary outcomes are patient-reported disability 30 days after surgery (validated WHODAS tool) and prospectively collected in-hospital complications (validated POMS tool). 750 participants (375/arm) will provide 98% power for disability (control mean score 35 (SD 25; MID=8)) and 90% power for complications (55% complication rate (25% relative risk reduction)) (=0.025; 2 pair-wise comparisons).

Expertise: Our team features multidisciplinary clinical and methodological experts, nationally representative knowledge users and patient representatives.

Expected outcomes: Older people with frailty are a growing and vulnerable segment of the surgical population and are under-represented in existing studies. Exercise prehabilitation is a high-priority research question which may be most relevant to people with frailty given their physical and physiologic vulnerabilities. This study, featuring patient-reported outcomes and an integrated knowledge translation approach will produce generalizable findings directly relevant to patients, families, caregivers, and knowledge users.