Factors related to the incorrect use of inhalers by asthma patients

To evaluate inhaler technique in outpatients with asthma and to determine associations between the correctness of that technique and the level of asthma control.

This was a cross-sectional study involving patients > 14 years of age with physician-diagnosed asthma. The patients were recruited from the Asthma Outpatient Clinic of the Hospital de Clínicas de Porto Alegre, in the city of Porto Alegre, Brazil. The patients completed two questionnaires (a general questionnaire and an asthma control questionnaire based on the 2011 Global Initiative for Asthma guidelines), demonstrated their inhaler technique, and performed pulmonary function tests. Incorrect inhaler technique was defined as the incorrect execution of at least two of the predefined steps.

We included 268 patients. Of those, 81 (30.2%) showed incorrect inhaler technique, which was associated with poor asthma control (p = 0.002). Logistic regression analysis identified the following factors associated with incorrect inhaler technique: being widowed (OR = 5.01; 95% CI, 1.74-14.41; p = 0.003); using metered dose inhalers (OR = 1.58; 95% CI, 1.35-1.85; p < 0.001); having a monthly family income < 3 times the minimum wage (OR = 2.67; 95% CI, 1.35-1.85; p = 0.008), and having > 2 comorbidities (OR = 3.80; 95% CI, 1.03-14.02; p = 0.045).

In the sample studied, incorrect inhaler technique was associated with poor asthma control. Widowhood, use of metered dose inhalers, low socioeconomic level, and the presence of > 2 comorbidities were associated with incorrect inhaler technique.