Relationships between repeated instruction on inhalation therapy, medication adherence, and health status in chronic obstructive pulmonary disease

PURPOSE Adherence to inhalation therapy is a critical determinant of the success of chronic obstructive pulmonary disease (COPD) management. However, in practice, nonadherence to inhalation therapy is very common in COPD patients. The effects of adherence to inhalation therapy in COPD have not been fully studied, and less is known about the relationship between medication adherence and quality of life in COPD. Our aim is to assess the factors that contribute to adherence to inhalation therapy and examine their correlation with quality of life. PATIENTS AND METHODS A cross-sectional analysis of 88 COPD patients was performed using a self-reported adherence questionnaire with responses on a 5-point Likert scale. RESULTS Of the 88 patients who were potential participants, 55 (63%) responded with usable information. The only significant factor associated with the overall mean adherence score was receiving repeated instruction about inhalation techniques (P = 0.032). Of the 55 respondents, 22 (40.0%) were given repeated verbal instruction and/or demonstrations of inhalation technique by a respiratory physician. Significant correlations were found between the overall mean adherence score and the health-related quality of life score (St George's Respiratory Questionnaire: total, r = -0.35, P = 0.023; symptoms, r = -0.43, P = 0.002; impacts, r = -0.35, P = 0.011). Furthermore, patients with repeated instruction showed better quality of life scores than those who did not receive instruction (total, P = 0.030; symptoms, P = 0.038; impacts, P = 0.019). CONCLUSIONS Repeated instruction for inhalation techniques may contribute to adherence to therapeutic regimens, which relates to better health status in COPD.