Cardiopulmonary Exercise Testing Provides Additional Prognostic Information in Cystic Fibrosis.

Hebestreit H; Hulzebos EHJ; Schneiderman JE; Karila C; Boas SR; Kriemler
S; Dwyer T; Sahlberg M; Urquhart DS; Lands LC; Ratjen F; Takken T;Varanistkaya L; Rucker V; Hebestreit A;
Usemann J; Radtke T; PrognosticValue of CPET in CF Study Group.

American Journal of Respiratory & Critical Care Medicine. 199(8):987-995,
2019 04 15.

RATIONALE: The prognostic value of cardiopulmonary exercise testing (CPET)
for survival in cystic fibrosis (CF) in the context of current clinical
management, when controlling for other known prognostic factors, is

OBJECTIVES: To determine the prognostic value of CPET-derived measures
beyond peak oxygen uptake ( V. o2peak) following rigorous adjustment for
other predictors.

METHODS: Data from 10 CF centers in Australia, Europe, and North America
were collected retrospectively. A total of 510 patients completed a cycle
CPET between January 2000 and December 2007, of which 433 fulfilled the
criteria for a maximal effort. Time to death/lung transplantation was
analyzed using Cox proportional hazards regression. In addition,
phenotyping using hierarchical Ward clustering was performed to
characterize high-risk subgroups.

MEASUREMENTS AND MAIN RESULTS: Cox regression showed, even after
adjustment for sex, FEV1% predicted, body mass index (z-score), age at
CPET, Pseudomonas aeruginosa status, and CF-related diabetes as covariates
in the model, that V. o2peak in % predicted (hazard ratio [HR], 0.964; 95%
confidence interval [CI], 0.944-0.986), peak work rate (% predicted; HR,
0.969; 95% CI, 0.951-0.988), ventilatory equivalent for oxygen (HR, 1.085;
95% CI, 1.041-1.132), and carbon dioxide (HR, 1.060; 95% CI, 1.007-1.115)
(all P < 0.05) were significant predictors of death or lung
transplantation at 10-year follow-up. Phenotyping revealed that
CPET-derived measures were important for clustering. We identified a
high-risk cluster characterized by poor lung function, nutritional status,
and exercise capacity.

CONCLUSIONS: CPET provides additional prognostic information to
established predictors of death/lung transplantation in CF. High-risk
patients may especially benefit from regular monitoring of exercise
capacity and exercise counseling.