Non-invasive ventilation (NIV) does not influence blood neutrophil count in COPD

Introduction: Ventilatory failure in COPD is associated with poor clinical outcomes. Neutrophils are key mediators in COPD pathogenesis. Aim: To investigate if NIV initiation influences blood neutrophil count in COPD patients with chronic hypercapnic respiratory failure. Methods: Retrospective observational cohort study of COPD patients with chronic hypercapnic respiratory failure setup on NIV at a tertiary ventilation unit between November 2017–June 2025. Demographics, medical history, number of exacerbations in the year prior to and post NIV setup, and first available blood test results before and after NIV setup were recorded. Data presented as: mean ± standard deviation, median (interquartile range) or number (proportion). Data analysed using Wilcoxon test and univariate ANCOVA. Results: Characteristics of 127 included participants summarised in Table 1. erjor;12/suppl_17/103/TB1 T1 TB1 Table 1: Participant characteristics Mean age in years ± SD 67 ± 9 Female, n (%) 72 (57) COPD, n (%) 86 (68) COPD/OSA overlap, n (%) 41 (32) Current Smoker, n (%) 28 (22) FEV1 % predicted 37 Triple Therapy, n (%) 95 (75) Median Pre NIV neutrophil count (IQR) 5.86 (4.1-7.4)×10⁹/L Median post NIV neutrophil count was 5.80 (4.2-7.7)×10⁹/L. There was no change in neutrophil count pre/post NIV (p=0.23). FEV1 %predicted did not predict post NIV neutrophil count (p=0.061). Total number of exacerbations reduced from 258 in the year prior, to 159 in the year post NIV setup (median change -1 (-2–0.25)), p=