Association between health-related quality of life outcomes and pulmonary function testing.

INTRODUCTION Investigations in associations between subjective health-related quality of life (HRQoL) measures and objective clinical assessments in patients with early-onset scoliosis (EOS) are limited. The purpose of this study is to investigate the association between pulmonary function rated by parents and pulmonary function testing (PFT) in patients with EOS. MATERIALS/METHODS In this cross-sectional study, patients with EOS at any stage of treatment from 2011 to 2018 were identified in 2 registries including 33 centers. Parents' perception of pulmonary function was evaluated using pulmonary function (PF) domain in the Early-Onset Scoliosis 24 item Questionnaire (EOSQ-24). PFT measures included FVC% predicted, FEV1/FVC, and TLC% predicted. All PFT predicted values utilized arm span. PFT and EOSQ-24 questionnaire were completed within 180 days of each other with an average day difference of 26 days. RESULTS 176 patients (mean age: 10.4 years old, female: 56%) were identified. 33% of patients were of congenital/structural etiology, 27% neuromuscular, 26% syndromic, and 14% idiopathic. Wide variance and lower scores of PF domain were reported by parents at lower FVC% predicted values (< 50%). As FVC% predicted values increased, PFD scores increased with simultaneous decreases in variance with few exceptions. CONCLUSION More variability and frequent lower pulmonary function values are reported by parents when percent forced vital capacity (FVC%) is < 50%. This likely reflects the degree to which children adapt to restrictive lung disease and the limits on adaptation that occur increasingly as lung function falls below 50% predicted. As a direct linear association with high correlation was expected, more research into the character of what the PF domain is measuring is necessary. LEVEL OF EVIDENCE IV.