Comparing 6-Year Carbon Footprint Between GINA Track 1 and 2 Asthma Management for Adults: A Real-World Primary Care Report from Singapore to Advocate for Policy Change in Inhaler Procurement

Background: Global Initiative for Asthma (GINA) has recommended inhaled corticosteroid (ICS)-Formoterol as Track-1 treatment for patients. Using ICS and SABA (Short-Acting Beta-Agonist) as a reliever is an alternative Track-2 option. Both modalities are tied to type of inhaler use, dry powder inhalers (DPI) and propellent-containing metered-dose inhalers (pMDI). Compared to propellent-free DPI, pMDI have much higher carbon footprint (CF) detrimental to the environment. Leveraging on dispensed inhaler data from the electronic medical records of patients managed in primary care, the study aimed to quantify their CF using Budesonide-Formoterol (BUD-FOR) DPI alone, compared to those who were treated with BUD-FOR DPI + pMDI as a reliever. Methods: Electronic medical records from 8 public primary care clinics were analysed, covering adult asthma patients (aged ≥21) between 2018 and 2023. Data on inhaler dispensing, asthma control test (ACT) scores and rescue therapy (RT) needs were assessed. CF was computed based on inhaler canisters dispensed. Associations between treatment modality, asthma control, RT and CF were analysed using Generalized Estimating Equations. Results: A total of 5634 patients using BUD-FOR DPI were included. Over the study period, Track-1 usage increased substantially from 466 to 2317 patients, while Track-2 rose modestly from 628 to 758. In 2023, 78.5% of patients achieved good asthma control compared to 68.7% in Track-2. The total CF per patient was substantially lower in Track-1 compared to Track-2 (3.3 vs 62.4 kgCO₂e). Patients in Track-1 had a significantly lower CF by 60 kgCO₂e ( P < .001), had 1.5 times higher odds to achieve good asthma control based on ACT scores ( P < .001) and had approximately 30% lower odds of receiving RT ( P < .001). The average number of SABA-pMDI canisters dispensed per patient declined from 2.8 to 2.1 over the study period. BUD/FOR inhalers use per patient per year was consistently higher in Track 2 compared to Track 1, with an average difference of 1.2 canisters (5.3 vs 4.1). Conclusion: Patients managed under Track-1 treatment approach demonstrated significantly better asthma outcomes and lower CF. These findings highlight potential of Track-1 treatment as the preferred strategy, enabling better clinical outcomes and reduced environmental impact.