Respiratory Biologics Utilization, Prescription Predictors, and Outcomes in Patients With Asthma and Comorbid Overweight or Obesity.

Abstract

Patients with asthma and elevated body mass index have higher baseline exacerbation risk and vulnerability to corticosteroid adverse effects. Yet evidence on the use and efficacy of respiratory biologics, which reduce these risks, in patients with obesity is lacking. To test the hypothesis that respiratory biologics are underused in eligible patients with obesity. This is a retrospective observational analysis of adult patients with active, moderate to severe asthma and with a body mass index of 25 kg/m² or greater in the electronic health records of a large US health system (2018-2023). We included patients meeting US Food and Drug Administration-specified eligibility criteria. Primary outcomes were biologic prescription and time to prescription. Secondary outcomes were change in exacerbation rates and factors associated with biologic prescription. Exploratory outcomes were biologic eligibility using obesity-adjusted eosinophil counts (≥ 96cells/μL) and use compared with a healthy weight cohort. We included 5,805 patients with asthma and overweight or obesity who were eligible for a biologic. Of these, 11.9% were prescribed biologics. Of the biologic-eligible cohort, 59.8% had obesity and 10.4% of those patients were prescribed biologics. In adjusted analyses, obesity reduced prescription odds and time to initiation. Subspecialist care was the strongest prescription predictor. Annualized exacerbation rates significantly declined across type 2 biologics users with obesity. Use of obesity-adjusted eosinophil criteria expanded biologics eligibility by 11.3% without clear exacerbation benefit. Only a fraction of eligible patients with asthma and comorbid obesity receive biologics despite meeting type 2 biomarker criteria, compared with patients with overweight or healthy weight. These data may substantially inform health services research and therapeutic interventions to improve asthma management.