Removing race from pulmonary function tests in children with idiopathic scoliosis

To evaluate the impact of switching from race-specific to race-neutral pulmonary function tests (PFT) equations in Black versus White children with idiopathic scoliosis according to 1) a minimum clinically important difference (MCID: > 10%) in forced vital capacity percent predicted (FVC%); 2) between-group differences in achieving normal lung function (FVC ≥ 80%); and 3) greater FVC% changes from race-specific to race-neutral than changes from surgery after 2 years.

This single-institution retrospective review in the southwestern United States included the PFTs of 1413 (314 Black, 1099 White) children 14.4 ± 2.2 years with idiopathic scoliosis. Curves averaged 63° before spinal fusion between 2002 and 2024; 550 had 2-year follow-up. PFTs were recalculated using race-specific and race-neutral equations.

Preoperatively, race-specific equations showed similar FVC% between groups (86% Black vs. 84% White). Recalculating with race-neutral equations shifted Black FVC% downward by 8% and White FVC% upward by 5%, creating a 14% between-group difference exceeding the MCID. Under race-neutral equations, the proportion of Black children achieving "normal" lung function (FVC ≥ 80%) dropped from 66 to 44%, while White children increased from 63 to 74%. Shifting from race-specific to race-neutral equations resulted in a larger change in FVC% than the actual physiological change measured two years post-fusion.

In children with idiopathic scoliosis requiring fusion, race-specific PFTs overestimate FVC% in Black children and underestimate FVC% in White children, resulting in clinically important differences. Adopting race-neutral PFT equations prevents overestimating lung function in Black children with scoliosis, promoting more equitable, accurate assessments.