Inhalation Adherence Among Older Males with Chronic Obstructive Pulmonary Disease: A Structural Equation Model Applying the Theory of Planned Behavior

Objectives: Theoretical frameworks such as the theory of planned behavior (TPB) may provide a basis to study psychological factors associated with inhalation adherence among individuals with chronic obstructive pulmonary disease (COPD). The present study was designed to assess the predictability of TPB constructs for adequate adherence to inhalation therapy among this population. Methods: Using convenience sampling, 374 Taiwanese males with COPD (mean age: 72.69 years [SD??9.53] completed the Intention of Inhaled Medication Adherence Scale (which is based on TPB constructs), and the Test of Adherence to Inhalers Questionnaire. Structural equation modeling (SEM) was used to assess direct/indirect associations and likely mediating mechanisms. Results: The SEM model indicated a good fit and demonstrated the direct effects of subjective norms (β=0.254, p=0.003) and attitude (β=0.186, p=0.018) on adherence intention. There was also an indirect association between subjective norms and adherence through behavioral intention (β=0.039; p=0.046). Conclusions: The TPB appears to be a suitable theoretical framework to assess inhalation adherence among individuals with COPD. Further research is warranted using the theory among individuals with different sociodemographic variables affected by COPD as well as those with other respiratory conditions.