Determinants of Medication Nonadherence Among Diverse Adults With Chronic Obstructive Pulmonary Disease.

Introduction: High rates of medication nonadherence contribute to poor outcomes in chronic obstructive pulmonary disease (COPD), but the mechanisms driving nonadherence remain poorly understood. Methods: We conducted qualitative semistructured interviews to evaluate barriers and facilitators of inhaler adherence. The Capability, Opportunity, and Motivation model of Behavior informed the semistructured interview guide and analysis. Results: Short-term lapses in inhaler use commonly resulted from inhaler unaffordability, not possessing the inhaler, forgetfulness, and geographical or logistical issues accessing health care services. Participants overcame these barriers by requesting more affordable inhalers, keeping inhalers in strategic locations, routinizing inhaler use, utilizing reminders or cues, having extra inhalers, and leaning on social support. Nearly half of participants reported using their inhalers differently than prescribed because of insufficient knowledge, skills, or complex motivational barriers. Participants who reported using an incorrect dosage schedule or poor inhaler technique were unaware of their inhaler misuse. Although participants collectively saw some benefit to using inhalers, many were intentionally nonadherent due to conflicting motivational factors. Common motivational barriers to adherence included beliefs that inhalers were not always necessary, nonadherence carried little risk, their self-identity conflicted with having COPD, and emotional distress related to numerous medications. There were strong interactions between reinforcement and other motivational factors that created feedback loops which strengthened or weakened adherence. Conclusions: Barriers to medication adherence were common and varied by individual. Knowledge and skills barriers are well-suited for interventions that utilize instruction or enablement, whereas motivational barriers could be addressed through reinforcement or interventions tailored at the individual level.