Research Article: Exercise capacity in patients with cystic fibrosis vs. non-cystic fibrosis bronchiectasis

Date Published: June 13, 2019

Publisher: Public Library of Science

Author(s): Ronen Bar-Yoseph, Anat Ilivitzki, Dan M. Cooper, Michal Gur, Gur Mainzer, Fahed Hakim, Galit Livnat, Zeev Schnapp, George Shalloufeh, Merav Zucker-Toledano, Yael Subar, Lea Bentur, Anne Lee Solevåg.


Bronchiectasis is associated with morbidity, low exercise capacity and poor quality of life. There is a paucity of data on exercise capacity using cardiopulmonary exercise test (CPET) in non-cystic fibrosis (CF) bronchiectasis. Our aim was to compare exercise capacity using CPET in CF and non-CF bronchiectasis patients.

Cross-sectional retrospective/prospective controlled study assessing CPET using cycle ergometer. Exercise parameters and computed tomography (CT) findings were compared. Results: Hundred two patients with bronchiectasis and 88 controls were evaluated; 49 CF (age 19.7 ± 9.7 y/o, FEV1%predicted 70.9 ± 20.5%) and 53 non-CF (18.6 ± 10.6 y/o, FEV1%predicted 68.7 ± 21.5%). Peak oxygen uptake (peak V˙O2) was similar and relatively preserved in both groups (CF 1915.5±702.0; non-CF 1740±568; control 2111.0±748.3 mL/min). Breathing limitation was found in the two groups vs. control; low breathing reserve (49% in CF; 43% non-CF; 5% control) and increased V˙E/V˙CO2 (CF 31.4±4.1, non-CF 31.7±4.1 and control 27.2 ± 2.8). Oxygen pulse was lower in the non-CF; whereas a linear relationship between peak V˙O2 vs. FEV1 and vs. FVC was found only for CF. CT score correlated with V˙E/V˙CO2 and negatively correlated with V˙O2/kg and post exercise oxygen saturation (SpO2).

CPET parameters may differ between CF and non-CF bronchiectasis. However, normal exercise capacity may be found unrelated to the etiology of the bronchiectasis. Anatomical changes in CT are associated with functional finding of increased V˙E/V˙CO2 and decreased SpO2. Larger longitudinal studies including cardiac assessment are needed to better study exercise capacity in different etiologies of non-CF bronchiectasis., registration number: NCT03147651.

Partial Text

Bronchiectasis is associated with considerable morbidity and poor quality of life [1,2]. Often, a distinction is made between bronchiectasis caused by cystic fibrosis (CF) and non-CF bronchiectasis. The etiology for non-CF bronchiectasis include primary ciliary dyskinesia (PCD), post infectious, aspiration, primary and secondary immunodeficiency, congenital malformation, idiopathic and others [3]. While management and follow up strategies for PCD are usually extrapolated from CF, for the other non-CF bronchiectasis etiologies data is scarce.

This study was conducted in accordance with the amended Declaration of Helsinki. The study was approved by the Helsinki Committee (Institutional Review Board) of Rambam Health Care Campus (application number 0048-15-RMB), and Written consent was obtained from patients over the age of 18 years or from parents of minors prior to initiating CPET in the prospective part. This was a cross-sectional retrospective (2013–2016)/prospective (Since 2017) study population. The study was performed during a single visit in a CPET lab, situated in a tertiary university-affiliated medical center. The retrospective study included data analysis of patients who performed exercise tests as part of their clinical evaluation. Inclusion criteria for both groups were: evidence of bronchiectasis by CT, age > seven years, height > 125cm, and completed a maximal CPET test according to the accepted criteria. Exclusion criteria were preforming submaximal CPET, lack of data from the exercise test, exacerbation of patient’s condition within 30 days before the exercise evaluation, other chronic diseases affecting test results and according to the American College of Sports Medicine (ACSM) guidelines [14]. Control group was consisted of age and sex matched healthy subjects previously recruited as control for other studies in our lab or healthy subjects who were referred to our institute with a minor exercise complain and found to have no exercise limitations.

A total of one hundred and two patients (49 CF and 53 non-CF bronchiectasis patients) and 88 age and sex matched controls were included in the data analysis (Table 1). No adverse events were recorded. Non-CF bronchiectasis etiologies is summarized in Table 2. Two subjects in the control group did not perform spirometry due to technical issues.

This cross-sectional retrospective/prospective controlled study evaluated CPET in a large CF and non-CF bronchiectasis cohort and compared the results to a control group. Peak V˙O2 was relatively preserved while both groups had breathing limitation (low breathing reserve and elevated V˙E/V˙CO2). Oxygen pulse%pred was lower compared to CF and control; whereas a linear relationship between peak V˙O2 and FEV1 and peak V˙O2 vs. FVC was found only for CF patients. CT score correlated with V˙E/V˙CO2 and negatively correlated with V˙O2/kg and post exercise SpO2.




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