Effects of a short self-management interventionfor patients with asthma and diabetes: Evaluating health-related quality of life using then-test methodology

Despite intensive outpatient care and optimized medical treatment, some patients with chronic illnesses experience prolonged difficulties in the self-management of their illness and fail to attain optimal disease control. The present study describes the effects of an intervention programme aimed at improving self-management and quality of life among patients with asthma and diabetes. The intervention was based on insights from self-regulation theory and proactive coping theory. Patients with asthma (N = 70) and diabetes (N = 55) were randomly assigned to an intervention group or control group (standard care). In addition to a conventional pre-test–post-test–follow-up design, the then-test methodology was employed to examine the effects on quality of life. The present study showed no intervention effects on self-efficacy, self-care activities or proactive coping. The same was true for quality of life when measured with the conventional design. However, positive intervention effects for asthma patients were found on global quality of life and physical health when measured with the then-test procedure. These results accentuate the value of including then-tests when measuring intervention outcomes. Additional subgroup analyses showed that patients who scored relatively high on optimism at baseline, benefited more from the intervention than did patients who scored relatively low on optimism.