Long-Term Weight Changes After Starting Anti–IL-5/5Ra Biologics in Severe Asthma: The Role of Oral Corticosteroids

Background: Many patients with severe asthma are overweight or obese, often attributed to unintentional weight gain as a side effect of oral corticosteroids (OCSs). Anti–IL-5/5Ra biologics significantly reduce OCS use, but their long-term effects on weight are unknown. Objectives: To examine (1) weight change up to 2 years after anti–IL-5/5Ra initiation in subgroups on the basis of maintenance OCS use at start of treatment and (2) whether cumulative OCS exposure before or changes in OCS exposure during treatment are related to weight change. Methods: Real-world data on weight and cumulative OCS dose from adults included in the Dutch Registry of Adult Patients with Severe asthma for Optimal DIsease management before and at least 2 years after starting anti–IL-5/5Ra were analyzed using linear mixed models and linear regression analyses. Results: For the included 389 patients (55% female; mean body mass index, 28 ± 5 kg/m²; 58% maintenance OCS), mean weight decreased −0.27 kg/y (95% CI, −0.51 to −0.03; P =.03), with more weight loss in patients with maintenance OCS use than in those without maintenance OCS use (−0.87 kg/y [95% CI, −1.21 to −0.52; P <.001] vs +0.54 kg/y [0.26 to 0.82; P <.001]). Greater weight loss at 2 years was associated with higher cumulative OCS dose in the 2 years before anti–IL-5/5Ra initiation (β = −0.24 kg/g; 95% CI, −0.38 to −0.10; P <.001) and, independently, greater reduction in cumulative OCS dose during follow-up (β = 0.27 kg/g; 95% CI, 0.11 to 0.43; P <.001). Conclusions: Anti–IL-5/5Ra therapy is associated with long-term weight reduction, especially in patients with higher OCS exposure before treatment and those able to reduce OCS use during treatment. However, the effect is small and does not apply to all patients, and so additional interventions seem necessary if weight change is desired.