Immediate and One-Year Outcomes of an Asthma-Tailored Pulmonary Rehabilitation Programme in Overweight and Obese People with Difficult-to-Treat Asthma

Introduction: Management of difficult-to-treat asthma is particularly challenging in people with elevated body mass index (BMI). Our randomised controlled trial of pulmonary rehabilitation (PR) showed improved outcomes at 8 weeks. Here we assess immediate and one-year effects of asthma-tailored PR in participants with difficult-to-treat asthma and BMI >= 25 kg/m(2), and identify response predictors.<br /> Methods: A prospective observational study of PR, tailored to asthma, comparing outcomes at baseline (V1), immediately after 8 weeks of PR (V2), and at 1 year (V3). Baseline characteristics were compared in responders/non-responders defined by achievement of minimum clinically important difference (MCID) for asthma control questionnaire (ACQ6) (0.5) at 8 weeks and 1 year.<br /> Results: Of 92 participants, 56 attended V2 and 45 attended V3. Mean age was 60 (SD 13) years, 60% were female, and median (IQR) BMI was 33.8 (29.5- 38.7) kg/m(2). At V1, V2, and V3, respectively, there were significant differences in ACQ6 (mean (95% CI): 2.5 (2.1- 2.9), 2.2 (1.8- 2.5), and 2.3 (1.9- 2.7), p< 0.003), Borg breathlessness score post-6-minute walk test (median (IQR): 2 (0.5- 3), 1 (0- 2), and 1 (0.5- 2), p< 0.035), and annualised exacerbations requiring prednisolone (median (IQR): 3 (2- 5), 0 (0- 4.7), and 1.5 (0- 4.2), p< 0.003). A total of 27/56 (48%) had improvements >MCID for ACQ6 at V2 and 16 (33%) at V3. Participants with higher ACQ6 scores at baseline (suggesting poorer asthma control) were more likely to achieve MCID. Baseline BMI, within the range studied, was not predictive.<br /> Conclusion: Pulmonary rehabilitation induced improvements in asthma-related outcomes including perception of breathlessness, asthma control, and exacerbation frequency at 1 year. Those with poorer baseline asthma control were more likely to benefit.