Exploring the Effects of Pulmonary Rehabilitation and its Determinants in Lung Transplant Candidates with Cystic Fibrosis.

Abstract

Background/rationale: Lung transplant (LTx) candidates with cystic fibrosis (CF) have ventilatory and musculoskeletal limitations and benefit from pulmonary rehabilitation (PR). Their training response has not been well characterized. The study aims to: 1) characterize the effect of outpatient PR and 2) evaluate the clinical characteristics associated with their PR response.

Methods: Single-center retrospective cohort study of CF LTx candidates (July 2009-June 2019) with available pre-transplant exercise data, who participated in PR 2 to 3 times/week until transplantation. Demographics, CF-related characteristics, aerobic and muscle training volumes, and six-minute walk distance (6MWD) were characterized using descriptive statistics, paired t-tests and Spearman correlations to describe relationships between CF-related characteristics and training volumes.

Results: In 86 CF LTx candidates (32±10 years, 49% males, FEV1: 23±5%; listing 6MWD 421±89 meters), the median PR time was 87 days (24-36 sessions). 78% had at least one exacerbation and 55% required hospitalization. 88% used supplemental oxygen and 37% required home non-invasive ventilation. Treadmill speed (1.7±0.5 mph); biceps (50 IQR [40-70] lbs*reps) and quadriceps (30 IQR [30-40] lbs*reps) training volumes improved with PR (p< 0.05), whereas 6MWD remained unchanged. The presence of ≥ 1 respiratory exacerbation was associated with a lower progression in treadmill speed [-0.36 mph 95%CI (-0.67 to -0.04), p=0.028].

Conclusion: CF LTx candidates participating in PR increased treadmill speed and muscle training volumes, with preservation of 6MWD. Respiratory exacerbations were prevalent and important determinants of aerobic training.