The Association of COPD Patients' and Caregivers' KAP with Inhaler Adherence: An Actor-Partner Interdependence Model...

Chronic obstructive pulmonary disease (COPD) is a leading cause of global mortality, yet inhaler adherence remains suboptimal. Caregivers may play a critical role in patients' medication behavior, but the underlying mechanisms are poorly understood. This study aimed to examine the actor and partner effects of knowledge, attitude, and practice (KAP) levels among COPD patients and their caregivers on patient inhaler adherence.

Using convenience sampling, 150 COPD patient-caregiver dyads were recruited from a tertiary hospital in Xuzhou, China, between March and June 2026. KAP levels were assessed using a self-designed questionnaire, and patient inhaler adherence was evaluated using the Chinese version of the Test of Adherence to Inhalers (TAI). Data were analyzed within the Actor-Partner Interdependence Model (APIM) framework with paired cluster-robust standard errors. Seven pre-specified covariates were adjusted, and all continuous variables were standardized using Z-scores before model inclusion.

The mean TAI score was 42.5 ± 9.8, with 63.3% of patients showing low adherence. The actor effect of patient KAP on their own adherence was significant (β = 0.141, P = 0.016; β* = 0.152), and the partner effect of caregiver KAP on patient adherence was also significant (β = 0.293, P < 0.001; β* = 0.537). Sensitivity analysis revealed that the attitude dimension exerted the strongest partner effect (β* = 0.566, P < 0.001), which was significantly stronger than practice (β* = 0.488, P = 0.001) and knowledge (β* = 0.394, P < 0.001).

Caregiver KAP is more strongly associated with patient inhaler adherence than patients' own KAP, with the attitude dimension playing a dominant role. Clinical interventions targeting caregivers as a core strategy, shifting the focus from knowledge transfer to belief reshaping and behavioral skill training, may hold promise for improving inhaler adherence, although prospective studies are needed to confirm these associations.