A systematic review of frailty changes following solid organ transplantation: Is it all about the frailty tool?

Frailty is increasingly recognized among patients with advanced organ disease (AOD). Solid organ transplantation (SOT) improves survival rates of patients with AOD and also impacts frailty status. However, there is considerable heterogeneity in frailty changes post-SOT reported in the literature. This study aims to determine whether the type of frailty tool contributes to heterogeneity in frailty outcomes after transplantation.

We searched PubMed, Embase, MEDLINE, Scopus, and Web of Science up to 1 August 2025 for studies assessing frailty before and after SOT in adults. Frailty tools were classified as phenotypic or deficit accumulation tools. Meta-analyses were conducted on baseline prevalence and changes in prevalence, with subgroup analyses by tool type and organ type. Narrative synthesis described changes in frailty scores, state transitions, and domain-specific outcomes across early, intermediate, and late post-transplant stages.

Forteen studies (n = 3443) were included. Overall, phenotypic tools consistently captured reductions in frailty prevalence during the intermediate stage (6-12 months) post-transplant (mean difference, MD: -0.09; 95 % CI: -0.12 to -0.07; I² = 0 %). In contrast, studies using deficit accumulation tools showed inconsistent results with high heterogeneity (MD: -0.19; 95 % CI: -1.18 to 0.79; I² = 96.9 %). The organ-specific subgroup analysis revealed substantial heterogeneity within organ groups. Improvements in frailty scores and transitions to non-frail states were more frequently observed with the phenotypic tools with physical domains such as grip strength and activity improvement, while some deficit accumulation tools demonstrated deterioration.

Phenotypic frailty tools consistently detect improvements during intermediate post-SOT recovery, while deficit accumulation tools yield variable findings, highlighting the importance of appropriate frailty tool choice.