Factors Associated with 6-Minute Walk Distance Improvement During Outpatient Pulmonary Rehabilitation After Lung Transplantation.

Abstract

Rationale Pulmonary rehabilitation (PR) is recommended after lung transplantation to optimize recovery. Prior studies have evaluated intensive or specialized PR protocols rather than the 36-session comprehensive outpatient model specified by Medicare. Objectives We evaluated 6-minute walk distance (6MWD) improvement and factors associated with rehabilitation response in a Medicare PR program. Methods We conducted a pragmatic cohort study of 367 lung transplant recipients participating in PR from 2013-2025. The primary outcome was 6MWD. Registry data were linked to obtain pre-transplant demographic, clinical and functional data. Factors associated with 6MWD improvement were evaluated through multivariable regression, inverse probability weighting and machine learning models. Results Among 367 lung transplant recipients, 286 (78%) completed discharge assessments with median 6MWD improvement of 171 meters (m, 61% relative improvement). Baseline functional capacity was inversely associated with 6MWD improvement (-0.6m per 1m baseline increase [95% CI, -0.7 to -0.5]). Female sex (-44.2m [-64.0 to -24.3]), longer hospital stay (-0.7m/day [-1.3 to -0.1]), and higher BMI (-3.2m per kg/m² [-5.5 to -1.0]) were associated with less improvement. Higher baseline depression scores were paradoxically associated with greater gains (2.4m/PHQ-9 point [0.04 to 4.67], p Conclusions In this analysis of outpatient PR linked to transplant registry data, lung transplant recipients achieved substantial functional improvements. Post-transplant baseline function was inversely associated with gains while pre-transplant disease severity showed no significant association, suggesting removal of ventilatory constraints creates relatively uniform rehabilitation potential. These findings support the real-world effectiveness of the Medicare outpatient PR model.