A LARGE UK cohort study has found that, while biologic therapies improve asthma control across all BMI categories, patients with obesity experience persistently worse outcomes, suggesting a need for combined treatment approaches.
Obesity is a well-recognised comorbidity in severe asthma, associated with higher symptom burden and poorer outcomes, particularly among women. To explore whether obesity alters response to biologic therapies, researchers analysed data from the UK Severe Asthma Registry, which includes patients treated at regional severe asthma services nationwide. Clinical outcomes between baseline and first annual review were assessed by BMI category, ranging from healthy weight to severely obese, and by biologic treatment status.
Among 1,956 patients included, 1,477 (75.5%) commenced a biologic agent during follow-up. At baseline, asthma control worsened progressively with increasing BMI, with higher Asthma Control Questionnaire-6 (ACQ-6) scores and more frequent exacerbations, emergency department attendances, and hospital admissions. Biologic treatment produced significant improvements in ACQ-6 scores in overweight, obese, and severely obese patients compared with those not receiving biologics. However, disparities in outcomes persisted, with mean ACQ-6 scores following treatment ranging from 1.3 in the healthy weight group to 2.8 in the severely obese group (p<0.001). Biologics also reduced exacerbation rates across all BMI groups, though this effect was not observed in severely obese patients.
These findings indicate that biologics provide important benefits across BMI categories, but patients with obesity remain more likely to have uncontrolled disease due to poorer baseline status. Incorporating weight-loss strategies alongside biologic therapy may therefore be essential, and further studies evaluating the role of newer pharmacotherapies for weight reduction in this patient population are warranted.
Reference
Gonem S et al; UK Severe Asthma Registry. Effects of obesity on response to asthma biologic treatment: Longitudinal data from the United Kingdom Severe Asthma Registry. J Allergy Clin Immunol Pract. 2025; DOI:10.1016/j.jaip.2025.07.041.
