Patient satisfaction, inhaler use, adherence, and asthma control

BACKGROUND: We sought to compare treatment satisfaction with inhaled medications among asthmatics using a metered-dose inhaler (MDI) or a dry-powder inhaler (DPI), and to correlate satisfaction with treatment adherence, pulmonary function, and airway inflammation.
METHODS: Spirometry, fraction of expired nitric oxide (FENO), and asthma control were assessed in 200 adult subjects with asthma (69 men, 131 women) using MDI or DPI. Treatment satisfaction with inhaled therapy was assessed with the Treatment Satisfaction Questionnaire for Medication (TSQM) in 4 domains: Effectiveness, Side Effects, Convenience, and Global Satisfaction. The Medication Adherence Questionnaire (MAQ) was used to evaluate adherence to treatment. RESULTS: There were 115 and 85 subjects with asthma, using MDI and DPI, respectively. More MDI users (40.9%) had wellcontrolled asthma as compared to DPI users (17.6%). MDI users had greater treatment adherence and better TSQM domain scores for Effectiveness, Convenience, and Global Satisfaction than did DPI users. Multivariate linear regression analysis revealed no significant association between MDI/DPI use and TSQM domain scores. TSQM Convenience and Global Satisfaction domain scores were significantly correlated with MAQ scores (Spearman’s coefficients 0.211 and 0.218, P .003 and P .002, respectively). There was no significant correlation between any TSQM domain score and pulmonary function or FENO concentration.
CONCLUSIONS: MDIs were associated with better disease control and treatment adherence among subjects with asthma. Both MDI and DPI are likely to provide equivalent treatment satisfaction.