Spirometry thresholds for clinical trial eligibility: time for urgent re-evaluation.

Bokobza, Idan; Le Sayec, Melanie; Bossley, Cara; Brugha, Rossa; Davies, Jane Carolyn; Dawson, Charlotte; Holt, Lucy; Hughes, Dominic A et al. · Thorax · 2025

Where this comes from

Abstract

A common eligibility criterion in respiratory clinical trials is a per cent-predicted forced expiratory volume in 1 second (ppFEV<sub>1</sub>) between 40% and 90%, using the ethnicity-dependent Global Lung Function Initiative (GLI)-2012 spirometry reference equations. International societies now endorse the newer 'race-neutral' GLI-Global equations. We quantify the impact on trial eligibility of switching from GLI-2012 to GLI-Global for the UK Cystic Fibrosis Registry (n=8182). In a future trial with a maximum eligibility threshold of ppFEV<sub>1</sub>=90%, the changes in ppFEV<sub>1</sub> would lead to over 700 people becoming newly ineligible. Urgent review of fixed ppFEV<sub>1</sub> thresholds is required, with an initial recommendation to widen the range to 30-95% ppFEV<sub>1</sub> when GLI-Global is implemented to ensure equitable access for people of all ethnicities. There is also a wider need to review the use of fixed ppFEV<sub>1</sub> spirometry limits for trial eligibility.

Medical subject headings