Carbon Emissions and Treatment Efficiency in Chronic Obstructive Pulmonary Disease: The Impact of Inhaled Bronchodilators and Corticosteroids.

BACKGROUND

Inhaled therapies are essential for chronic obstructive pulmonary disease (COPD) management but also contribute to healthcare-related carbon emissions. Real-world evidence linking inhaler-related carbon burden to clinical outcomes remains limited. This study evaluated the relationship between inhaler-related CO2 emissions and clinical effectiveness of different treatment regimens.

METHODS

This retrospective single-center observational study included patients with COPD. Patients were categorized into four groups based on the inhaled therapy: long-acting muscarinic antagonists (LAMA) monotherapy, LAMA/long-acting β2-agonists (LABA), LABA/inhaled corticosteroids (ICS), and triple therapy (LAMA/LABA/ICS). Clinical outcomes, including pulmonary function test (PFT) parameters and health-related quality of life (HRQL), were assessed over one year. Total inhaler-related CO2 emissions were calculated using published conversion factors. Emission-adjusted outcomes were derived to evaluate the clinical benefits per unit of CO2 emission.

RESULTS

Clinical improvements in HRQL and PFT were comparable across groups, with no significant differences in ΔFEV1, ΔFVC, or ΔCAT. However, CO2 emissions differed significantly, being the lowest in the LAMA monotherapy group and the highest in the LABA/ICS and triple therapy groups (p < 0.001). Emission-adjusted analysis demonstrated that lower-intensity regimens, particularly LAMA monotherapy, were associated with more favorable CO2-adjusted treatment efficiency, particularly in ΔmMRC/CO2 (p = 0.001) and ΔFEV1 (%)/CO2 (p = 0.026), indicating higher clinical benefit per unit carbon emission. After adjustment for baseline severity-related variables, including age, sex, smoking status, baseline FEV1, baseline CAT score, and baseline mMRC score, higher-intensity regimens remained associated with lower CO2-adjusted pulmonary function improvement compared with LAMA monotherapy.

CONCLUSION

High-intensity regimens were associated with substantially increased inhaler-related CO2 emissions. Although major clinical outcomes were generally comparable across groups, lower-emission regimens showed relatively more favorable CO2-adjusted outcomes in this cohort. These findings highlight the importance of balancing clinical effectiveness with environmental considerations while maintaining guideline-based, individualized COPD management according to disease severity and clinical needs.