Radtke T; Department of Paediatric Respiratory and Sleep Medicine, Edinburgh, United Kingdom.
Urquhart DS; Braun J; Barry PJ; Waller I; Petch N; Mei-Zahav M;
Kramer MR; Hua-Huy T; Dinh-Xuan AT; Innes JA; McArthur S; Sovtic A;
Gojsina B; Verges S; de Maat T; Morrison L; Wood J; Crute S; Williams CA;
Tomlinson OW; Bar-Yoseph R; Hebestreit A; Quon BS; Kwong E; Saynor ZL;
Causer AJ; Stephenson AL; Schneiderman JE; Shaw M; Dwyer T; Stevens D;
Remus N; Douvry B; Foster K; Benden C; Ratjen F; Hebestreit H

Annals of the American Thoracic Society. 21(3):411-420, 2024 Mar. VI 1

Rationale: Cardiopulmonary exercise testing (CPET) provides prognostic
information in cystic fibrosis (CF); however, its prognostic value for
patients with advanced CF lung disease is unknown. Objectives: To
determine the prognostic value of CPET on the risk of death or lung
transplant (LTX) within 2 years.
Methods: We retrospectively collected data from 20 CF centers in Asia, Australia, Europe, and North America on
patients with a forced expiratory volume in 1 second (FEV1) 40% predicted
who performed a cycle ergometer CPET between January 2008 and December
2017. Time to death/LTX was analyzed using mixed Cox proportional hazards
regression. Conditional inference trees were modeled to identify subgroups
with increased risk of death/LTX. Results: In total, 174 patients (FEV1,
30.9% +/- 5.8% predicted) were included. Forty-four patients (25.5%) died
or underwent LTX. Cox regression analysis adjusted for age, sex, and FEV1
revealed percentage predicted peak oxygen uptake ([Formula: see
text]o2peak) and peak work rate (Wpeak) as significant predictors of
death/LTX: adjusted hazard ratios per each additional 10% predicted were
0.60 (95% confidence interval, 0.43-0.90; P = 0.008) and 0.60 (0.48-0.82;
P < 0.001). Tree-structured regression models, including a set of 11
prognostic factors for survival, identified Wpeak to be most strongly
associated with 2-year risk of death/LTX. Probability of death/LTX was
45.2% for those with a Wpeak 49.2% predicted versus 10.9% for those with
a Wpeak > 49.2% predicted (P < 0.001).
Conclusions: CPET provides prognostic information in advanced CF lung disease, and Wpeak appears to
be a promising marker for LTX referral and candidate selection.