Critical Errors in Inhaler Technique Among Patients With Asthma and COPD: A Cross-Sectional Study in a Real-World Setting.

BACKGROUND: The correct use of inhalation devices is essential for achieving adequate control of asthma and COPD; however, critical errors in inhalation technique are frequent and substantially reduce treatment effectiveness. This study's objective was to evaluate the prevalence of inadequate inhalation technique among patients with asthma and COPD and to identify the most common critical errors and the factors associated with incorrect use. METHODS: This cross-sectional observational study included 575 patients (aged ≥ 18 years) with asthma and/or COPD, recruited from a university hospital outpatient pulmonology clinic and a public specialized pharmacy (Natal, Brazil). Participants completed sociodemographic questionnaires and demonstrated their inhaler technique, which was assessed using device-specific checklists to identify critical errors. Factors associated with critical errors were analyzed using multivariable logistic regression. RESULTS: Only 8.2% of participants correctly performed all steps of the inhalation technique. At least one critical error was observed in 73.4% of the cohort. In multivariable analysis, advanced age (OR: 1.029; 95% CI: 1.016-1.044), use of multiple devices (OR: 2.500; 95% CI: 1.754-3.562), and type of mechanism independent of inspiration (OR: 0.262; 95% CI: 0.160-0.430; protective factor) were significantly associated with critical errors (p < 0.001). CONCLUSIONS: Inadequate inhalation technique, particularly the occurrence of critical errors, was highly prevalent, especially among older patients and those using multiple devices. Inhalers dependent on inspiratory effort demonstrated greater vulnerability to incorrect use.