ABSENCE OF EXHALATION BEFORE INHALER USE IS ASSOCIATED WITH SEVERE ACUTE EXACERBATION IN PATIENTS WITH COPD

Abstract

Background and Aims

Inhalers are essential for pharmacotherapy in airway diseases. Poorly use of the inhalers is associated with poor clinical outcomes. However, few studies have examined which kind of inhaler techniques have the most clinical significance. This study sought to investigate what stage of the inhaler technique is associated with severe acute exacerbations (SAE) of airway diseases.

Methods

Data from a prospective observational cohort which had enrolled patients with airway diseases including asthma and COPD, from two university hospitals, was used. SAE was defined as an exacerbation with an emergency room visit or hospitalization. These inhaler techniques of the subjects were checked by research assistants at the time of enrollment regardless of the class of prescribed inhalers : “open and hold device properly”, “load and prime device”, “exhale to residual volume slowly”, “inhale slowly and deeply”, “hold breath for 5-10 seconds” and “rinse mouth”. The association of the inhaler techniques with previous SAE in a year was analyzed.

Results

Of 350 participants, 75 (asthma: n=33/133, 44%; COPD: n=30/111, 40%; asthma-COPD overlap, ACO: n=12/51, 16%) had experienced SAE in the previous year. Overall, 62.8% of the subjects had proper inhaler techniques for the six items. Among these, only inadequate “exhale to residual volume slowly” was associated with the history of SAE (odds ratio, OR=2.39; confidence interval, CI=1.23-4.66) on multivariate logistic regression model adjusting covariates including age, gender, smoking history, dyspnea, percent of the predicted value in forced expiratory volume in one second. Interestingly, this association was significant only in the subjects with COPD (OR=6.20; CI=1.91-20.12), not asthma or ACO.

Conclusions

In this cohort of airway diseases, absence of “exhale to residual volume slowly” had a significant association with SAE, suggesting that exhalation before inhaler use should be emphasized in the education of patients, especially with COPD.