Objectives: The purpose of this study is to update previous systematic reviews of interventions targeting asthma self-care in adults with asthma, and to use meta-regression to examine the association between the use of specific behavior change techniques and intervention effectiveness.
Methods: Electronic bibliographies were searched systematically to identify randomized controlled trials of interventions targeting asthma self-care. Intervention content was coded using a published taxonomy of behavior change techniques. For trials with a low-to-moderate risk of bias, study outcomes were pooled using random effects meta-analysis. Associations between intervention content and effect size were explored using meta-regression.
Results: Meta-analysis of 38 trials (7883 patients) showed that interventions targeting asthma self-care reduced symptoms (standardized mean difference [SMD] = -0.38 [-0.52, -0.24]) and unscheduled health care use (odds ratio [OR] = 0.71 [0.56 to 0.90]) and increased adherence to preventive medication (OR = 2.55 [2.11 to 3.10]). meta-regression analyses found that "active involvement of participants" was associated with a reduction in unscheduled health care use (OR = 0.50 vs. 0.79). Inclusion of "stress management" techniques was associated with an increase in asthma symptoms (SMD = 0.01 vs. -0.44). Existing recommendations about the "optimal" content of asthma self-care interventions were tested but were not supported by the data.
Conclusions: Interventions targeting asthma self-care are effective. Active involvement of participants is associated with increased intervention effectiveness, but the use of stress management techniques may be counterproductive. Taxonomy-based systematic reviews using meta-regression have potential for identifying techniques associated with increased effectiveness in behavioral interventions.