Abstract
INTRODUCTION: Preterm-born children have their normal in-utero lung development interrupted, thus are at risk of short- and long-term lung disease. Spirometry and exercise capacity impairments have been regularly reported in preterm-born children especially those who developed chronic lung disease of prematurity (CLD) in infancy. However, specific phenotypes may be differentially associated with exercise capacity. We investigated exercise capacity associated with prematurity-associated obstructive (POLD) or prematurity-associated preserved ratio of impaired spirometry (pPRISm) when compared to preterm- and term-controls with normal lung function. MATERIALS AND METHODS: Preterm- and term-born children identified through home screening underwent in-depth lung function and cardiorespiratory exercise testing, including administration of postexercise bronchodilator, as part of the Respiratory Health Outcomes in Neonates (RHiNO) study. RESULTS: From 241 invited children, aged 7-12 years, 202 underwent exercise testing including 18 children with POLD (percent predicted (%)FEV(1) and FEV(1) /FVC < LLN); 12 pPRISm (%FEV(1) < LLN and FEV(1) /FVC ≥ LLN), 106 preterm-controls (PT(c) , %FEV(1) ≥ LLN) and 66 term-controls (T(c) , %FEV(1) > 90%). POLD children had reduced relative workload, peak O(2) uptake, CO(2) production, and minute ventilation compared to T(c) , and used a greater proportion of their breathing reserve compared to both control groups. pPRISm and PT(c) children also had lower O(2) uptake compared to T(c) . POLD children had the greatest response to postexercise bronchodilator, improving their %FEV(1) by 19.4% (vs 6.3%, 6% 6.3% in pPRISm PT(c,) T(c) , respectively; p < .001). CONCLUSION: Preterm-born children with obstructive airway disease had the greatest impairment in exercise capacity, and significantly greater response to postexercise bronchodilators. These classifications can be used to guide treatment in children with POLD.