Clinical burden of asynchrony in patients with asthma when using metered-dose inhalers for control.

Background: Asynchrony, or lack of coordination between inhalation and actuation when using a pressurized metered-dose inhaler (MDI), could theoretically impact the delivery of inhaled medications and treatment efficacy. Objective: To assess the real-world association between asynchrony and clinical outcomes among patients with asthma who receive controller therapy delivered by MDIs. Methods: A cohort of patients was assembled via electronic health records. The patients were aged >12 years, with one or more documentations of an asthma diagnosis, no diagnosis of chronic obstructive pulmonary disease, and two or more prescriptions for an inhalation aerosol corticosteroid alone or with long-acting beta-2-agonist delivered via MDI. Their inhaler technique, demonstrated by using a placebo MDI, was evaluated at a clinic visit by study nurses who used a standardized 10-step checklist. Asynchrony was defined as any gap in timing between inhalation and actuation. Clinical outcomes were assessed via electronic health records during the 6 months before,the clinic visit and were compared between patients with and patients without asynchrony by using multivariable regression analyses adjusted for age, gender, asthma severity proxy, and baseline comorbidities. Results: Of the total 254 eligible patients, mean age of 49.3 years, 90 males (35.4%), 32 (12.6%) had asynchrony. Patients with asynchrony had higher odds of an asthma exacerbation (adfisted odds ratio, 2.99; p = 0.009), and lower odds of risk domain asthma control (adjusted odds ratio, 0.41; p = 0.04) compared with patients without asynchrony. Conclusion: This study provided real-world evidence that asynchrony in MDI use among patients with asthma who were treated with controller MDIs was associated with clinical burden in terms of asthma exacerbations and control.