A 1-Year Weight Management Program for Difficult-to-Treat Asthma With Obesity: A Randomized Controlled Study.

Abstract

Background: Obesity-associated asthma results in increased morbidity and mortality. We report 1-year asthma outcomes with a weight management regimen, the Counterweight-Plus Programme (CWP), compared with usual care (UC) in a single-center, randomized controlled trial in patients with difficult-to-treat asthma and obesity.

Research question: Can use of the CWP result in improved asthma control and quality of life compared with UC at 1 year in patients with difficult-to-treat asthma and obesity?

Study design and methods: Adults with difficult-to-treat asthma and BMI ≥ 30 kg/m² were randomized (1:1 CWP:UC) to treatment. The CWP, with dietitian support, included a 12-week total diet replacement phase (850 kcal/d low-energy formula), and then subsequent food reintroduction and maintenance phases up to 1 year. Outcomes include results of the six-item Asthma Control Questionnaire (ACQ-6) and Asthma Quality of Life Questionnaire (AQLQ), as well as health care usage. A minimal clinically important difference (MCID) is 0.5 for ACQ-6 and AQLQ.

Results: Of 36 patients recruited, 29 attended visits at 52 weeks (13 CWP and 16 UC). The CWP resulted in greater weight change (median, -14 kg [interquartile range (IQR), -15 to -9 kg]) compared with UC (median, 2 kg [IQR, -7 to 8 kg]; P = .015) at 52 weeks. A greater proportion achieved MCID with the CWP vs UC in AQLQ (71% vs 6%, respectively; P < .001). No between-group differences were observed in ACQ-6. Median exacerbation frequency was reduced over 52 weeks with the CWP from 4 (IQR, 2 to 5) to 0 (IQR, 0 to 2) (P < .001), although no between-group difference was observed. Seventy percent of the CWP group lost ≥ 10% body weight and had improvement in ACQ-6 (mean difference, -1.1; 95% CI, -1.9 to -0.3; P = .018) and AQLQ (mean difference, 1.2; 95% CI, 0.4, 2.1; P = .011) across 52 weeks.

Interpretation: In this study, the use of a dietitian-supported weight management program resulted in sustained weight loss and is a potential treatment for obesity in asthma. The CWP resulted in a higher proportion achieving MCID improvements in AQLQ compared with UC. Within-group differences in AQLQ and exacerbation frequency suggest potential with the CWP. These encouraging signals justify a larger sample study to further assess asthma-related outcomes.