Longitudinal changes in exercise capacity among adult cystic fibrosis patients

Abstract

Introduction: Longitudinal data regarding changes in exercise capacity among adult cystic fibrosis (CF) patients are current-ly scarce. The aim of this brief report was to assess changes in exercise capacity among adult CF patients with stable and mild-to-moderate disease eight years after their initial evaluation. Material and methods: Maximum cardiopulmonary exercise testing (CPET) was utilized. Other assessments included Doppler echocardiography, the 6-minute walking test, spirometry, and lung volume evaluation. Results: Eleven (6 male, 5 female) patients completed both evaluations (initial and after eight years). During follow-up, indices of ventilatory impairment (such as ventilatory reserve; p=0.019, and ventilatory equivalent for carbon dioxide; p = 0.047) deterio-rated significantly following a decline in respiratory function measurements. Peak oxygen uptake (VO2), both as an absolute (26.6 ± 8.46 vs 23.89 ± 6.16 mL/kg/min; p = 0.098) and as a % of predicted value (71.21 ± 16.54 vs 70.60 ± 15.45; p = 0.872), did not deteriorate. This is also true for oxygen pulse (p = 0.743), left heart ejection fraction (p = 0.574), and pulmonary artery systolic pressure (p = 0.441). However, the anaerobic threshold, both as an absolute (p = 0.009) and as a % of predicted value (p = 0.047), was significantly lower during follow-up. Conclusion: In adult CF patients with stable, mild-to-moderate disease, a peak VO2 may be preserved for several years. However, even in these patients, deconditioning is present.