Multidimensional prognostic risk stratification of COPD exacerbations: the baseline, acuity, and trigger (BAt) model

Exacerbations punctuate the natural course of chronic obstructive pulmonary disease (COPD), posing a substantial burden on patients and health-care systems. Understanding the severity of an acute exacerbation of COPD (AECOPD) is crucial for stratifying mortality risk and guiding treatment decisions. Currently, the severity of an AECOPD is primarily graded on outcomes of health-care use. Given the complex heterogeneity in pathogenesis, clinical presentation, post-event trajectory, and patient perspectives, this approach does not adequately address the causes and extent of clinical deterioration or consider an individual's baseline status, upon which implementation of treatment and prevention of future exacerbations rely. We have conceptualised a multidimensional model to stratify the severity and prognostic risk of an AECOPD, incorporating three distinct domains: baseline functional status (B), the intensity of the event (acuity; A), and the causal trigger (t). The BAt classification for AECOPD could allow for more individualised prognostic and therapeutic implications. The validation process for this model is underway, with preliminary findings supporting its feasibility.