The effect of COPD exacerbation history on future exacerbation risk and mortality

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) report classifies individuals with chronic obstructive pulmonary disease (COPD) who have experienced ≥2 moderate (outpatient) or ≥1 severe (emergency department or hospitalization) exacerbations within the last year as being at high risk of future exacerbation (category E).

This study aimed to investigate the risk of exacerbation and death associated with the individual components of the GOLD E category.

We conducted a retrospective cohort study using health administrative data from Ontario, Canada (2007-2018). Individuals ≥65 years of age with physician-diagnosed COPD were followed for up to 5 exacerbations, until their death, or the study period ended. After each exacerbation, individuals were assigned to 1 of 3 GOLD subgroups: E moderate (≥2 moderate), E severe (≥1 severe), and AB (≤1 moderate). Under a landmark analysis framework, Fine-Gray subdistribution hazards (sdHR) competing risk models were created for each event, and the risk of exacerbation and death was estimated.

There were 279 798 individuals included. Individuals in the GOLD E moderate subgroup were at a higher risk of future exacerbation (COPD, chronic obstructive pulmonary disease exacerbations 3-5 = 1.16-1.23) and a lower risk of death (sdHR exacerbations 3-5 = 0.75-0.82) than GOLD AB individuals. In comparison, patients in the GOLD E severe subgroup were at lower risk of future exacerbation (sdHR exacerbations 2-5 = 0.89-0.95), but higher risk of death (sdHR exacerbations 2-5 = 1.56-1.59).

These findings indicate that COPD patients in the GOLD E moderate subgroup have a different risk of future exacerbation and death than individuals in the GOLD E severe subgroup.