Inhaled Therapy Adherence in COPD:A COM-B-Based Narrative Review of Determinants and Intervention Strategies

Medication adherence is defined as the extent to which patients take medications as prescribed by their healthcare providers, encompassing three critical dimensions: initiation (starting the prescribed therapy), implementation (taking doses correctly as scheduled), and persistence (continuing treatment for the recommended duration). Long-term management of chronic obstructive pulmonary disease (COPD) relies heavily on inhalation therapy; however, real-world adherence remains suboptimal, with reported medication possession ratios (MPR) typically ranging from 40% to 60% in observational studies. Poor adherence is associated with increased exacerbation frequency, accelerated lung function decline, and substantial healthcare costs.

Based on the Capability-Opportunity-Motivation-Behaviour (COM-B) model, this narrative review aims to summarize and conceptually organize existing literature on measurement methods, epidemiological status, influencing factors, and intervention strategies for inhalation medication adherence in COPD patients, with particular emphasis on adherence differences between single-inhaler triple therapy (SITT) and multiple-inhaler triple therapy (MITT).

A narrative review methodology was employed, utilizing purposing literature search combined with citation back-tracking. Observational studies and randomized controlled trials from PubMed, CNKI, and other databases (up to December 2024) were included, with influencing factors categorized according to COM-B dimensions. Quantitative estimates reported in this review are derived from individual observational studies with heterogeneous designs and populations, and should be interpreted as illustrative ranges rather than pooled or definitive values. Quantitative estimates are derived from heterogeneous observational studies and should be interpreted as illustrative rather than pooled values. The non-systematic, purposing nature of this review limits comprehensive generalizability.

Across the heterogeneous observational studies included in this review, MPR ≥80% was achieved by approximately 30% to 50% of patients in reported cohorts, while inhalation technique error rates were reported as illustrative ranges of 30% to 50%. The COM-B framework suggests that adherence deficits arise from the interplay of capability limitations (operational skill deficits), opportunity constraints (with the MITT associated with an illustrative range of approximately 12% to 14% lower MPR compared with SITT in reported real-world studies), and motivational barriers (with depression and anxiety associated with approximately 20% to 25% reductions in adherence in individual cohorts). In observational data, higher adherence has been associated with a reported 51% reduction in exacerbation-related hospitalization risk and an attenuation of forced expiratory volume in 1 second (FEV₁) decline by approximately 21 mL/year according to individual observational estimates. SITT was associated with improved treatment persistence compared with MITT in available real-world studies (18-month persistence rates ranging from approximately 2.3% for MITT to 16.5% for SITT). Promising intervention approaches described in the literature include artificial intelligence (AI)-based visual error-correction technology, device simplification strategies, and digital therapeutics, though evidence for some of these strategies remains preliminary.

Inhalation medication adherence in COPD represents a multidimensional behavioral syndrome. This review proposes that transitioning from traditional "one-size-fits-all" education models to precision stratified interventions based on the COM-B framework may enable more individualized chronic disease management, though further empirical validation of phenotype-stratified interventions is warranted. This phenotype-stratified model represents a conceptual framework advanced by the authors to stimulate future research, rather than an empirically validated clinical tool.