Treatable Traits in Long COVID: Inhaled corticosteroids and long-acting bronchodilators for small airway dysfunction among symptomatic Long COVID patients without known Asthma

Abstract Background and objectiveLong COVID is a chronic multi-system condition with limited treatment options. Small airway dysfunction (SAD), detectable by oscillometry or spirometry, may respond to inhaled corticosteroid/long-acting bronchodilator (ICS/LABA) therapy. We aimed to determine the prevalence and predictors of SAD in non-asthmatic long COVID patients and assess the impact of ICS/LABA.MethodsRetrospective study of adults with WHO-defined long COVID at St Vincent’s, Sydney (June 2022–October 2024). Patients with prior asthma or ICS/LABA use were excluded. Demographics, co-morbidities, spirometry, forced oscillation techniques (FOT), and C19-YRS were assessed at baseline, 6, 12, and 18 months. SAD was defined using Chiu et al. criteria. Outcomes were compared between SAD and non-SAD patients and by ICS/LABA use (p < 0.05 significant). Logistic regression identified predictors of SAD.ResultsOf 251 patients screened, 163 met inclusion and 123 (75.5%) had SAD. Compared to non-SAD, SAD patients were older (52.9 ± 14.9 vs. 42.2 ± 15.6 years, p < 0.001), with higher BMI (29.1 ± 6.5 vs. 24.4 ± 4.0, p < 0.001), and more hypertension, obesity, and ischaemic heart disease. FOT showed significantly higher resistance (R5, R19, R5–19), increased AX and Fres, and more negative X5 (all p < 0.05), while spirometry only detected lower FEV1. Among 79 SAD patients prescribed ICS/LABA, resistance, reactance, and symptoms improved significantly: dyspnoea (83.5%→17.7%), fatigue (96.2%→15.2%), cough (43%→11.4%).ConclusionSAD appears highly prevalent in long COVID patients without known asthma and is best detected by oscillometry. Treatment with ICS/LABA was associated with improved symptoms and FOT indices, however randomised trials are needed to confirm efficacy.