Introduction: Frailty is a strong predictor of adverse postoperative outcomes. Prehabilitation may improve outcomes after surgery for older people with frailty by addressing physical and physiologic deficits. The objective of this trial is to evaluate the efficacy of home-based multimodal prehabilitation in decreasing patient-reported disability and postoperative complications in older people with frailty having major surgery.

Methods and analysis: We will conduct a multicentre, randomised controlled trial of home-based prehabilitation versus standard care among consenting patients >60 years with frailty (Clinical Frailty Scale> 4) having elective inpatient major non-cardiac, non-neurologic or non-orthopaedic surgery. Patients will be partially blinded; clinicians and outcome assessors will be fully blinded. The intervention consists of > 3 weeks of prehabilitation (exercise (strength, aerobic and stretching) and nutrition (advice and protein supplementation)). The study has two primary outcomes: in-hospital complications and patient-reported disability 30 days after surgery. Secondary outcomes include survival, lower limb function, quality of life and resource utilisation. A sample size of 750 participants (375 per arm) provides >90% power to detect a minimally important absolute difference of 8 on the 100-point patient-reported disability scale and a 25% relative risk reduction in complications, using a two-sided alpha value of 0.025 to account for the two primary outcomes. Analyses will follow intention to treat principles for all randomised participants. All participants will be followed to either death or up to 1 year.

Ethics and dissemination: Ethical approval has been granted by Clinical Trials Ontario (Project ID: 1785) and our ethics review board (Protocol Approval #20190409-01T). Results will be disseminated through presentation at scientific conferences, through peer-reviewed publication, stakeholder organisations and engagement of social and traditional media.

Trial registration number: NCT04221295.