Frailty and longitudinal pulmonary function trajectories in lung transplant recipients

Abstract Background Frailty is increasingly recognized as a marker of biological vulnerability associated with adverse clinical outcomes. Lung transplant recipients may be particularly susceptible to frailty, yet its impact on longitudinal pulmonary function improvement after transplantation remains poorly understood. Methods Prospective longitudinal study (2-years follow-up) in lung transplant recipients. Physical frailty was assessed using the Fried phenotype. Pulmonary function parameters (vital capacity-VC, forced vital capacity-FVC, forced expiratory volume in 1 s-FEV1, and total lung capacity-TLC) were expressed as percentage of predicted values. Linear mixed-effects models were used to evaluate the association between baseline frailty burden and pulmonary function trajectories over time, adjusting for age, sex, body mass index, underlying respiratory disease category, and time from transplantation to baseline assessment. Results A total of 155 lung transplant recipients were included (mean age 48.7 ± 13.3 years; 43.2% female). According to the Fried phenotype, 43.7% were robust, 40.4% pre-frail, and 15.9% frail. Higher frailty burden was independently associated with lower baseline FVC, with borderline associations for VC and FEV1. Significant frailty-by-time interactions were observed for VC (β = 2.03, p = 0.010) and FVC (β = 2.20, p = 0.003), indicating steeper longitudinal improvement in spirometric values among participants with higher baseline frailty burden. A similar trend was observed for FEV1. Reduced handgrip strength and unintentional weight loss were the frailty components most consistently associated with pulmonary function trajectories. Conclusions These findings support the potential role of frailty assessment in identifying vulnerable transplant recipients who may benefit from personalized rehabilitative and multidimensional post-transplant interventions.