Rate of critical errors in inhaler device use in COPD and associated factors with poor inhaler technique: a multicenter study

<bold>Introduction–purpose:</bold> This study aimed to evaluate the inhaler technique of COPD patients in Turkey, detect the critical error rate in inhaler device use and assess the factors associated with inadequate inhaler technique. <bold>Method:</bold> Demographic data of COPD patients were collected in a multicenter, cross-sectional study. Parameters included COPD Assessment Test (CAT), mMRC dyspnea scale, GOLD stage, pulmonary function tests, previous inhaler training, exacerbation history, and oxygen/mechanical ventilation use. Inhaler device use steps were directly observed by the physician and pre-defined critical error steps were recorded. Patients' inhaler treatment adherence is classified as adherent and non-adherent to inhaler treatment according to the MARS-5 scale. <bold>Results:</bold> Patients(mean age:66.34±8.56 years, mean FEV1:49.79±20.64%)were predominantly GOLD stage E(56.9%) with comorbidities(73.7%). Critical error rate in inhaler use was 39.7%,and nonadherence was 29.9%. Factors associated with critical errors included lower education, older age, oxygen therapy use, higher mMRC score, multiple inhalers, poorer lung function, and severe exacerbations (p<0.05). Previous inhaler education correlated with fewer errors (p=0.003), while nonadherence related to higher error rates(p<0.001). <bold>Conclusion:</bold> 40%of COPD patients made critical errors in inhaler use, linked to advanced age, low education, respiratory impairment, dyspnea severity, and exacerbation risk. Particular attention should be paid to ensuring correct inhaler technique in patients with COPD who have disadvantage factors that lead to inadequate inhaler technique. Inhaler device training is specially important to achieve this goal.