P153 Associates of, and time to recovery from, eosinopenia in severe exacerbation of COPD (A-TREC)

Introduction
Blood eosinophil count (BEC) guides selection for inhaled corticosteroid (ICS) and emerging biologics in COPD. Neither GOLD nor NICE specify measuring BEC during clinical stability. 50% of patients admitted with severe exacerbation of COPD have transient eosinopenia (BEC <50 cells/uL).1

Aims
This preliminary analysis from the A-TREC study (clinicaltrials.gov NCT06188065) examines time to recovery in BEC in the subgroup with admission eosinopenia and an uneventful recovery; this will not alter target recruitment. We aim to recruit 200 patients to identify 69 with admission eosinopenia and an uneventful recovery.

Methods
Patients with a severe exacerbation of COPD and admission eosinopenia were assessed with measurement of BEC on days 3, 7, 14, 21, 28 and 42 following admission. Patients with an eventful recovery (further systemic corticosteroids or emergency hospital admission during follow up) were excluded. Stable-state was defined as day 42 BEC.

Results
102/113 patients have completed follow up; 34 had admission eosinopenia with an uneventful recovery. Mean (SD) age 72 (9) years, FEV1 39% (22%) predicted, median (IQR) eMRCD score 4 (4–5). 59% were female, 44% current smokers and 5.9% on LTOT. 26/34 (76%) recovered to stable-state BEC, and 32/34 (94%) crossed the 100 cell/uL threshold by day 28. 10/34 patients (29%) crossed the 300 cell/uL by day 28, with 1 further patient crossing by day 42. Only 7/34 (21%) and 3/34 (9%) crossed a new BEC treatment threshold beyond day 14 and 21 respectively. Additional data will be available for presentation at the BTS Winter Meeting.