B94-10 Comparative Effectiveness and Safety of Lower-Emission vs. Higher-Emission Inhalers in Asthma and COPD

Abstract Rationale Inhalers are an important source of health care greenhouse gas (GHG) emissions, largely due to propellant based metered-dose inhalers (MDI). Lower-emission inhalers, like dry powder inhalers (DPI), offer an alternative, but clinical evidence on comparative effectiveness of MDI versus DPI is mixed. We evaluated whether lower-emission DPIs are associated with a difference in clinical outcomes, compared to higher-emission MDIs, amongst new users with asthma and chronic obstructive pulmonary disease (COPD), in real-world clinical settings. Methods We conducted a retrospective cohort study in the single-payer, public health insurance plan of British Columbia, Canada. We included patients with newly diagnosed asthma or COPD in separate cohorts between January 1, 2000, and April 1, 2020, comparing patients who initiated long-acting therapy with lower-emission DPI versus higher-emission MDI, across the drug classes of long-acting beta-agonists (LABAs), inhaled corticosteroids (ICSs), and combination ICS/LABA. The primary outcome was the time to first moderate-severe asthma or COPD exacerbation. Secondary outcomes focused on medication safety, including community acquired pneumonia, major adverse cardiovascular events MACE, and stomatitis. We used propensity score inverse probability of treatment weighting with Cox proportional hazards models to assess the primary outcome. Results We identified 132,944 individuals with asthma and 23,693 individuals with COPD. Patients were followed for an average of 99.92 ± 247.81 days in the asthma cohort and 270.44 ± 535.18 days in the COPD cohort. Lower-emission DPI was not associated with a difference in time to first moderate-severe exacerbation in either asthma (hazard ratio HR 0.93; 95% confidence interval CI 0.83-1.05) or COPD (HR 0.92; 95% CI 0.85-1.00), compared to higher-emission MDI, within all medication classes. DPIs were comparable to MDIs for safety outcomes, including stomatitis (asthma incidence rate ratio IRR 0.97, 95% CI 0.78–1.21; COPD IRR 1.09, 95% CI 0.77–1.54) and MACE in asthma (IRR 0.87, 95% CI 0.68–1.12). DPIs were also associated with a lower rate of community acquired pneumonia (asthma IRR 0.79, 95% CI 0.72–0.87; COPD IRR 0.78, 95% CI 0.70–0.88) and MACE in COPD (IRR 0.77, 95% CI 0.64–0.93). Conclusions Among new users of long-acting inhalers with asthma and COPD, there was no difference in effectiveness using DPI versus MDI. Our study suggests DPI can be prescribed preferentially over MDI to lower global warming potential without evidence of patient harm. This abstract is funded by: None