Pilot randomised trial of a healthy eating behavioural intervention in uncontrolled asthma

Abstract

Rigorous research on the benefit of healthy eating patterns for asthma control is lacking. We randomised 90 adults with objectively confirmed uncontrolled asthma and a low-quality diet (Dietary Approaches to Stop Hypertension (DASH) scores <6 out of 9) to a 6-month DASH behavioural intervention (n=46) or usual-care control (n=44). Intention-to-treat analyses used repeated-measures mixed models. Participants were middle-aged, 67% female and multiethnic. Compared with controls, intervention participants improved on DASH scores (mean change (95% CI) 0.6 (0, 1.1) versus −0.3 (−0.8, 0.2); difference 0.8 (0.2, 1.5)) and the primary outcome, Asthma Control Questionnaire scores (−0.2 (−0.5, 0) versus 0 (−0.3, 0.3); difference −0.2 (−0.5, 0.1)) at 6 months. The mean group differences in changes in Mini Asthma Quality of Life Questionnaire overall and subdomain scores consistently favoured the intervention over the control group: overall 0.4 (95% CI 0, 0.8), symptoms 0.5 (0, 0.9), environment 0.4 (−0.1, 1.0), emotions 0.4 (−0.2, 0.9) and activities 0.3 (0, 0.7). These differences were modest, but potentially clinical significant. The DASH behavioural intervention improved diet quality with promising clinical benefits for better asthma control and functional status among adults with uncontrolled asthma. A full-scale efficacy trial is warranted.

Acceptability and feasibility of the ‘DASH for Asthma’ intervention in a randomized controlled trial pilot study

“…Despite these limitations, results from the present study provide context for why the 'DASH for Asthma' intervention increased participants' adherence to the DASH eating plan and the proportion of those achieving minimal clinically important improvement in asthma control (20) and inform how to refine the intervention and design future behavioural interventions in patients with uncontrolled asthma. Currently, there is a dearth of randomized controlled trials investigating whether behavioural interventions promoting a healthy dietary pattern can Table 5 Intervention class attendance by session in the 'DASH for Asthma' randomized controlled trial pilot study Session (%) I1 G2 G3 G4 G5 I6 G7 G8 G9 G10 I11 Session attended, as initially scheduled* 87 80 76 65 70 83 72 70 72 81 76 Make up sessions † 100 100 100 100 100 88 92 93 92 89 82 Options to make up sessions ‡ In-person individual 17 22 9 19 22 14 0 0 0 0 11 Telephone 83 45 73 31 7 14 17 8 0 0 56 Email § 0 33 18 50 71 72 83 92 100 100 33 DASH, Dietary Approaches to Stop Hypertension; I, individual session; G, group session.…”

“…Results on the potential efficacy of the 'DASH for Asthma' intervention were previously published (20) . Mixed methods integrating quantitative and qualitative approaches were used to evaluate acceptability and feasibility of the intervention.…”

“…At 6 months, eighty-three (92 %) participants were assessed and the results showed that the DASH behavioural intervention significantly improved diet quality and increased the proportion of participants achieving minimal clinically important improvement in asthma control among adults with uncontrolled asthma; thus a full-scale efficacy trial is warranted (20) . The purpose of the current article is to describe the behavioural intervention developed to promote adherence to the DASH eating pattern and to examine acceptability and feasibility of the intervention from the perspective of intervention participants and lifestyle coaches by (i) tracking participant class attendance and self-monitoring behaviour and (ii) conducting surveys with open-and closed-ended responses after each intervention session among participants and lifestyle coaches.…”

Use of a motivational interviewing-informed strategy in group orientations to improve retention and intervention attendance in a randomized controlled trial

“…Follow-up assessments were completed at 3 and 6 months. The trial protocol and primary findings were published previously [19,20].…”

“…As we have done in our previous RCTs [23][24][25][26], we implemented the following strategies to maximize retention: (1) careful staff selection and standardized training in rapport building, MI techniques, trialspecific protocols and problem solving techniques as applicable to their study roles; (2) legally sufficient and effective informed consent; (3) cautious eligibility screening, including assessment of willingness and motivation to adhere to data collection and treatment requirements; (4) edification of participants about the importance of follow-up assessments regardless of treatment adherence; (5) prudent participant incentives and flexible scheduling; (6) promotion of study identity; (7) ongoing monitoring of recruitment and retention; (8) up-todate contact information for the participant and two emergency contacts; (9) diligent efforts to re-engage inactive participants; and (10) prioritization of outcome measures when not all measures may be collected from a participant [19,20].…”