Biologic therapy impacts body composition in severe asthma

Key takeaways:

• The impact of biologic therapy on body composition in patients with severe asthma differs by sex.
• At 12 months, women had lower fat mass and men had slightly higher fat-free mass.

Adults with severe asthma using a biologic therapy for the first time experienced changes in body composition parameters at 1 year, according to a research letter published in Annals of the American Thoracic Society.

“One year after starting biologic therapy, female patients with severe asthma showed a decrease in BMI with a reduction in fat mass, whereas males showed a small improvement in fat-free mass,” Edith Visser, MSc, PhD, postdoctoral researcher at Medical Center Leeuwarden in the Netherlands, and colleagues wrote.

In a prospective study, Visser and colleagues assessed 48 adults (mean age, 53.5 years; 52% women) with severe asthma beginning biologic therapy for the first time to evaluate how the therapy impacts BMI, fat mass index (FMI) and fat-free mass index (FFMI) at 4 months and 12 months.

Benralizumab (Fasenra, AstraZeneca) was the most prescribed biologic (n = 28). Other biologics included dupilumab (n = 15; Dupixent; Sanofi, Regeneron), omalizumab (n = 3; Xolair; Genentech, Novartis), reslizumab (n = 1; Cinqair, Teva Pharmaceutical Industries Ltd.) and mepolizumab (n = 1; Nucala, GSK).

Of the total cohort, five patients stopped taking their therapy. Researchers also lost eight patients due to COVID-19 restrictions at the 12-month mark.

During analysis, researchers included a random intercept, covariates (sex and age) and a time-by-sex interaction term in linear mixed-effects models.

Mean baseline BMI was higher among women vs. men (29.4 kg/m² vs. 25.4 kg/m²), as was baseline FMI (12.6 kg/m² vs. 7.8 kg/m²). In contrast, men had a higher FFMI than women (mean, 17.5 kg/m² vs. 17 kg/m²).

Between baseline and 12 months, mean FMI among women went down by 1.18 kg/m² (P = .04). Mean BMI also decreased at this timepoint (–1.01 kg/m²) but was not statistically significant. Researchers did not observe any changes in FFMI in this group.

Despite not reaching significance, men showed a slight rise in FFMI by 0.38 kg/m² at the 12-month visit. Between baseline and the two follow-up visits, men’s mean BMI did not significantly differ.

As an additional analysis, researchers looked to see if there was a link between composition changes and better asthma outcomes, physical activity or oral corticosteroid use through questionnaires taken during follow-up visits.

In the cohort of women, researchers found a link between lower FMI at 12 months and better scores on the Asthma Control Questionnaire and the Asthma Quality of Life Questionnaire at 4 months.

Reduced FMI among men was linked to higher physical activity, a lower oral corticosteroid dose and lower FEV₁/FVC at 4 months.

Further, women with elevated FEV₁/FVC and physical activity during the 4-month follow-up had better 12-month FFMI, according to researchers.

Of the above correlations, researchers noted that only those observed in the cohort of women were significant after correction for multiple testing and should be viewed as “hypothesis generating.”

“Future studies in larger populations should examine whether specific changes in body composition after biologic therapy are related to improvements in asthma-related outcomes and what the underlying mechanisms are, because maintaining a healthy weight while preserving muscle mass is important in asthma management,” Visser and colleagues wrote.