Rehabilitation for Physical Frailty in Lung Transplant Candidates: A Systematic Review.

Purpose: Physical frailty is prevalent in lung transplant (LTx) candidates and is linked to adverse outcomes preoperatively and postoperatively. Exercise is beneficial in optimizing exercise capacity and quality of life in candidates, but its impact on physical frailty is unknown. Methods: We prospectively registered and published a protocol (PROSPERO CRD42022363730) before undertaking a systematic review. We searched 4 databases plus trial registries from 1980 to February 2024 for studies of exercise interventions in adults awaiting LTx. Outcomes were measures or surrogate markers of physical frailty. An NIH assessment tool was used to assess study quality, and certainty of evidence was assessed using GRADE. Results: Fifteen studies (664 patients) were included. Interventions were in-person pulmonary rehabilitation, home exercise, and telerehabilitation. Studies included aerobic, resistance, balance, and breathing training. Only 2 studies assessed frailty using a phenotypic measure. Studies demonstrated improvement in some surrogate frailty outcomes including the Short Physical Performance Battery, 5 times sit-to-stand test, and handgrip or muscle strength measures. The study quality was fair or poor; evidence was low or very low certainty for all outcomes due to imprecision and high risk of bias. Uncontrolled study designs and heterogeneity of interventions and outcomes limit conclusions on effectiveness. Conclusions: Exercise training appears beneficial in modifying surrogate markers of physical frailty before LTx, but conclusions are limited by low or very low certainty evidence. High quality randomized trials are needed to determine the impact of exercise interventions on physical frailty and to develop guidelines for LTx prehabilitation.