Impact of Comorbidity Burden on Acute NIV Outcomes Before and After COVID-19: A Charlson Comorbidity Index Analysis

Background: The effect of comorbidity burden on outcomes of acute non-invasive ventilation (NIV), and how this has evolved since COVID-19, is not well established. We investigated the association between Charlson Comorbidity Index (CCI), NIV outcomes, and mortality across pre- and post-COVID admissions. Methods: We conducted a cohort study of adults receiving acute NIV for hypercapnic respiratory failure at a tertiary centre. Patients were divided into two time periods: pre-COVID (04/2015–03/2020) and post-COVID (04/2020–03/2024). Demographics, clinical characteristics, and outcomes were compared. CCI was assessed overall and within diagnostic subgroups using non-parametric methods. Results: Among 3,212 patients (median age 72 years [IQR 61–77]; 59% female), median CCI rose significantly over time (4.0 vs. 5.0, p