Efficacy of brief motivational interviewing to improve adherence to inhaled corticosteroids among adult asthmatics: results from a randomized controlled pilot feasibility trial

Purpose: Daily adherence to inhaled corticosteroid (ICS) regimens is one of the most important factors linked to achieving optimal asthma control. Motivational interviewing (MI) is a client-centered communication style that focuses on enhancing intrinsic motivation to engage in appropriate self-management behaviors. MI has been shown to improve a variety of health behaviors including medication adherence in other disorders, but its efficacy for the improvement of ICS adherence in asthmatics has yet to be examined. This pilot "proof of concept" trial assessed the feasibility of MI to improve daily ICS adherence and asthma control levels in adult asthmatics.

Methods: Fifty-four poorly controlled (Asthma Control Questionnaire [ACQ] score ≥1.5), highly nonadherent (filled <50% of ICS medication in the last year) adult asthmatics were recruited from the outpatient asthma clinic of a university-affiliated hospital. Participants underwent baseline assessments and were randomly assigned to MI (3×30 minutes sessions within a 6-week period, n=26) or a usual care (UC) control group (n=28). ICS adherence (% pharmacy refills) and asthma control (ACQ, Asthma Control Test [ACT]) were measured at 6 and 12 months postintervention. Mixed model repeated measure analyses for both intent-to-treat and per-protocol were used. Results were adjusted for a priori-defined covariates including baseline adherence. Patients in the MI group also reported their impressions of the intervention.

Results: Six-month adjusted intent-to-treat analyses revealed a mean change in the percentage of ICS refills of 13% in the MI group vs 6% in the UC group (between group net improvement associated with MI =+6% [-12% to 24%]). Twelve-month analyses revealed a mean change in the percentage of ICS refills of 11% (MI group) vs 7% in the UC group (between group net improvement associated with MI =+3% [-11% to 18%]) representing an effect size (ES) of d=0.20 (medium). Six-month adjusted net improvement in ACQ and ACT scores between MI and control groups was -0.2 and +0.7, respectively, with improvements being even more pronounced at 12 months (ACQ =-0.5; ACT =+1.1; ES, d=0.12 and 0.18 [small], respectively). Interestingly, 6- and 12-month net improvements in asthma self-efficacy (which is specifically targeted by MI) improved by +0.4 and +0.4, respectively, with an ES of d=0.46 (marginally large). Patients in the MI group rated the intervention overwhelmingly positively in terms of usefulness, pertinence, feasibility, enjoyableness, and likelihood to change adherence behavior.

Conclusion: Results suggest that a brief (90 minutes) MI intervention that targets ICS adherence can produce clinically significant improvements in adherence behavior, asthma control levels, and asthma self-efficacy in poorly controlled nonadherent asthmatics at 6 months that are maintained for 1 year, and it is well accepted by patients. Future studies including larger sample sizes, modified intervention designs (eg, MI "booster" sessions), and assessments of the extent behavior changes translate into clinical improvements (eg, in asthma control and quality of life) are warranted.