A pragmatic, randomised controlled trial of a tailored pulmonary rehabilitation package in difficult-to-control asthma associated with elevated body mass index

Background Difficult-to-control asthma associated with elevated body mass index (BMI) represents a significant challenge, with limited treatment options. The effects of pulmonary rehabilitation (PR) in this population are uncertain.

Methods This randomised controlled trial compared an asthma-tailored PR programme to usual care (UC) in participants with uncontrolled asthma and BMI ≥25 kg/m2. PR comprised an hour of education and of exercise each week for eight weeks. Primary outcome was difference in change in Asthma Quality of Life Questionnaire (AQLQ) in PR versus UC groups post intervention. Secondary outcomes included difference in change in other asthma outcomes including asthma control questionnaire-6 (ACQ6), Medical Research Council (MRC) dyspnoea score, six-minute walk distance (6MWD) and post-exercise Borg breathlessness score. Responder analyses compared proportions reaching the minimum clinically important difference (MCID) for AQLQ and ACQ6.

Results 95 participants were randomised 1:1 to PR or UC; median age was 54, with 60% female and median BMI 33.8kg/m2. 18 participants withdrew prior to second visit, meaning 77 were included in analysis. Median (IQR) change in AQLQ was not significantly different: 0.3(-0.2 to 0.6) in PR and -0.1(-0.5 to 0.4) in UC, p= 0.139. There was no difference in proportion reaching MCID for improvement in AQLQ: 13(39%) in PR and 10(23%) in UC, p=0.184. Mean change in ACQ6 was significantly different: -0.4(95% CI -0.6 to -0.2) in PR and 0(-0.3 to +0.3) in UC, p=0.015*. In ACQ6 responder analysis, MCID was reached by 18 participants in PR group (54.5%) versus 10 in UC (22.7%), p=0.009*. Changes in MRC dyspnoea score (p=0.022*), 6MWD (p=0.035*) and Borg breathlessness (p=0.015*) were significantly different in favour of PR. A post-hoc analysis of PR group revealed baseline FeNO was significantly lower in ACQ6 responders (median (IQR) 18(8.5–41)) than non-responders (47(17–71)), p=0.020*; and in AQLQ responders (14(8.5–44.5)) compared to non-responders (40(19–71)), p=0.038*.

Conclusion Pulmonary rehabilitation improves asthma control and reduces perception of breathlessness in participants with difficult-to-control asthma associated with elevated BMI. It should be considered as additional therapy for this group. Lower FeNO in PR responders suggests it may be of most value in type-2 low phenotype obese asthma.