Introduction and objectives Standard of care treatments for asthma and COPD are commonly administered in single-dose or multidose dry powder inhalers. There is a dearth of evidence around the prevalence of comorbidities, especially those that may affect inhaler device handling, among Swedish asthma and COPD patients.

Methods This retrospective study from the Swedish National Health Registries included 495,254 patients receiving inpatient or specialised outpatient care in Sweden between January 1, 2005 and December 31, 2014. Estimates of severity were based on number of asthma/COPD drugs used. Diagnostic codes were used to assess number of patients with a pre-specified comorbidity potentially affecting device handling.

Results Patient characteristics, treatments and comorbidities are summarised in the Table. Comorbidities that may impact inhaler handling were observed in 15.8% (asthma), 50.4% (COPD) and 55.3% (asthma/COPD) patients; incidence was increased with disease severity (patients with severe disease: 26.3%, 52.0%, 55.9%) and advanced age (patients 60–69 years: 33.2%, 45.2%, 50.5%, respectively).

Conclusions Comorbidities potentially affecting device handling were common across all groups, and unexpectedly high among elderly asthma patients. Furthermore, the data indicate that a substantial percentage of patients use two or more separate inhalers. These findings highlight the need for newer, easier to use inhalers, as well as training and monitoring of device use in patients who may have more difficulties using their devices correctly due to comorbidities.