Device type and real-world effectiveness of asthma combination therapy: an observational study

Selection of inhaler device type appears to influence real-world effectiveness of inhaled corticosteroids (ICS), but data are lacking on the role of inhaler device in ICS and long-acting β2-agonist (LABA) combination therapy for asthma.

This retrospective matched cohort study compared 1-year asthma outcomes for UK patients initiating fixed-dose combination (FDC) fluticasone-salmeterol delivered by pressurised metered-dose inhaler (pMDI) versus dry powder inhaler (DPI). Patients with asthma aged 4-80 years receiving a first prescription for FDC fluticasone-salmeterol by pMDI or DPI were matched on baseline demographic and asthma severity measures. Co-primary outcomes were asthma control (a composite measure comprising no recorded hospital attendance for asthma, oral corticosteroids, or antibiotics for lower respiratory infection) and exacerbation rate.

Compared with the DPI cohort (n = 1567), patients in the pMDI cohort (n = 1567) had significantly greater odds of achieving asthma control during the outcome year (odds ratio [OR] 1.19; 95% confidence interval [CI] 1.01 to 1.40). Exacerbation rate was lower but not significantly in the pMDI cohort (adjusted rate ratio for pMDI cohort, 0.82; 95% CI 0.66 to 1.00). The odds of treatment success (defined as no exacerbations and no change in asthma therapy) was significantly greater in the pMDI cohort (OR 1.23; 95% CI, 1.07 to 1.42).

For UK primary care patients, pMDIs appear to achieve better asthma control outcomes than DPIs for delivery of FDC fluticasone-salmeterol. Pragmatic trials are needed to further investigate real-world outcomes with different inhaler devices for combination therapy.