Effects of a behaviour change intervention aimed at increasing physical activity on clinical control of adults with asthma: study protocol for a randomised controlled trial

Background: In adults with asthma, physical activity has been associated with several asthma outcomes. However, it is unclear whether changes in physical activity, measured via an accelerometer, have an effect on asthma control. The objective of the present study is, in adults with moderate-to-severe asthma, to investigate the effects of a behaviour change intervention, which aims to increase participation in physical activity, on asthma clinical control. Methods: This is a single-blind (outcome assessor), two-arm, randomised controlled trial (RCT). Fifty-five participants with moderate-to-severe asthma, receiving optimized pharmacological treatment, will be randomly assigned (computer-generated) into either a Control Group (CG) or an Intervention Group (IG). Both groups will receive usual care (pharmacological treatment) and similar educational programmes. In addition to these, participants in the IG will undergo the behaviour change intervention based on feedback, which aims to increase participation in physical activity. This intervention will be delivered over eight sessions as weekly one-on-one, face-to-face 40-min consultations. Both before and following the completion of the intervention period, data will be collected on asthma clinical control, levels of physical activity, health-related quality of life, asthma exacerbation and levels of anxiety and depression symptoms. Anthropometric measurements will also be collected. Information on comorbidities, lung function and the use of asthma medications will be extracted from the participant's medical records. Discussion: If successful, this study will demonstrate that, in adults with asthma, a behavioural change intervention which aims to increase participation in physical activity also affects asthma control.