Validation of the Modified Shuttle Test to Predict Peak Oxygen Uptake in Youth Asthma Patients Under Regular Treatment

Background: Oxygen uptake (VO(2)) evaluations by cardiopulmonary exercise test is expensive and time-consuming. Estimating VO(2) based on a field test would be an alternative. Objective: To develop and validate an equation to predict VO(2peak) based on the modified shuttle test (MST). Methods: Cross sectional study, with 97 children and adolescents with asthma. Participants were divided in two groups: the equation group (EG), to construct the equation model of VO(2peak), and the cross-validation group (VG). Each subject performed the MST twice using a portable gas analyzer. The peak VO(2peak) during MST was used in the equation model. The patients’ height, weight, gender, and distance walked (DW) during MST were tested as independent variables. Results: The final model [-0.457 + (gender × 0.139) + (weight × 0.025) + (DW × 0.002)] explained 87% of VO(2peak) variation. The VO(2peak) predicted was similar to VO(2peak) measured by gas analyzer (1.9 ± 0.5 L/min and 2.0 ± 0.5 L/min, respectively) (p = 0.67), and presented significant ICC 0.91 (IC95% 0.77 to 0.96); p < 0.001. The Bland–Altman analysis showed low bias (-0.15 L/min) and limits of agreement (-0.65 to 0.35 L/min). There was no difference in DW between EG (760 ± 209 m) and VG (731 ± 180 m), p = 0.51. Conclusion: The developed equation adequately predicts VO(2peak) in pediatric patients with asthma.