Objective: To explain adherence to prophylactic asthma medication (PAM, inhaled corticosteroids) by the attitude, social influence, and self-efficacy (ASE) model added with the concept of habit strength and to study whether habit moderates or mediates relationships between ASE factors and adherence.
Methods: A mail-out survey was conducted among 139 asthmatic adults. Multiple regression analysis was conducted, with self-reported adherence as the outcome and ASE factors and habit as the independent variables. Simple slope analyses and bootstrapping mediation analyses were also conducted.
Results: Having more severe asthma, taking PAM habitually, and perceiving few negative consequences of taking PAM were associated with better adherence. Self-efficacy influenced adherence indirectly through habit. The relationship between social norms and adherence was moderated by habit: In the case of weak habits, a supportive norm in a patient's environment toward taking PAM was positively related to PAM adherence; in the case of strong habits, a supportive norm led to less adherence.
Conclusion: Interventions to increase adherence should enhance the formation of habits by stimulating patients to perform the behavior frequently in similar situations by increasing self-efficacy and providing environmental cues, such as reminder devices and pill organizers. In addition, the disadvantages of PAM use should be negated.
Copyright © 2011 Elsevier Inc. All rights reserved.