Acute Exercise Challenge and Airway Dynamics in Youth With Sickle Cell Anemia: A Multicenter Study

Sickle cell anemia (SCA) leads to reduced physical functioning and cardiopulmonary fitness. Prior studies suggest that airway hyperresponsiveness to bronchoprovocation testing is common in SCA, but the prevalence of exercise-induced bronchospasm (EIB) is understudied. We hypothesized that EIB is more common in children with SCA than in controls. Non-asthmatic subjects 10-21 years old with SCA and race-matched controls underwent (1) maximal Cardiopulmonary Exercise Testing (CPET) by cycle ergometry and (2) a Controlled Intensity Interval Test (CIIT) consisting of eight bouts of constant workload cycling, randomized to 50% (moderate) or 70% (vigorous) of peak workload. Spirometry was performed pre/post CPET and CIIT. Multivariable logistic regression models tested associations between SCA status and EIB in response to CPET and CIIT. Compared to controls, subjects with SCA demonstrated lower hemoglobin, reduced baseline spirometry values, and decreased CPET maximal workload. Baseline lower airway obstruction and completion rates for CPET and CIIT were similar between groups. No adverse events occurred. The percentage of participants who met criteria for EIB did not differ between subjects and controls after CPET (21% vs. 26%, p = 0.537) or CIIT (32% vs. 17%, p = 0.126). In adjusted models, SCA status was not associated with EIB after CPET or CIIT. EIB was not more common in subjects with SCA versus controls after maximal CPET or submaximal exercise challenge of longer duration. Further research is needed to inform the development of exercise guidelines and to better understand the effects of exercise on airway dynamics in SCA. Trial Registration: ClinicalTrials.gov identifier: NCT03653676.