Asthma & Obesity: Low Biologic Use Despite Exacerbation Reduction

For adults with asthma and obesity, advanced therapies known as respiratory biologics offer significant relief from frequent exacerbations – sudden worsening of symptoms. However, a modern analysis reveals these potentially life-changing medications are significantly underprescribed in this high-risk population. The findings, published in the Journal of Allergy and Clinical Immunology Practice, underscore disparities in access to care and highlight the need for improved identification of eligible patients and streamlined prescribing practices.

Biologics and the Asthma-Obesity Connection

Asthma affects millions worldwide, and its impact is often amplified in individuals with obesity. People with asthma and a body mass index (BMI) of 25 kg/m² or higher experience a greater risk of asthma attacks and are more susceptible to adverse effects from traditional treatments like corticosteroids. Respiratory biologics, which target specific components of the immune system driving asthma inflammation, represent a newer class of medications that can offer a more targeted and potentially safer approach. Understanding the treatment burden in asthma is crucial for improving patient outcomes.

Researchers from a large U.S. Health system retrospectively analyzed electronic health records from 2018 to 2023, focusing on adults with moderate-to-severe asthma and a BMI of 25 or greater who met the Food and Drug Administration (FDA) criteria for respiratory biologics. The study included 5,805 patients. Despite meeting eligibility requirements, only 11.9% were actually prescribed a biologic medication. This gap was even more pronounced among those with obesity, where the prescription rate dropped to 10.4%.

Barriers to Access and the Role of Specialists

The study pinpointed several factors contributing to this underutilization. Obesity itself was associated with a lower likelihood of receiving a prescription and a longer delay in treatment initiation. This suggests that higher BMI may create barriers to accessing these advanced therapies, even when patients meet the necessary biomarker criteria.

A key finding was the strong association between specialist care and biologic prescription rates. Subspecialist care emerged as the strongest predictor of prescription, suggesting that referral patterns, access to specialized biomarker testing, and ongoing management by specialists are critical for ensuring eligible patients receive appropriate treatment. This highlights a potential need to improve communication and collaboration between primary care physicians and pulmonologists or allergists.

Real-World Effectiveness and Biomarker Considerations

For obese patients who *did* receive T2-directed respiratory biologics (targeting the interleukin-5 pathway), the study demonstrated a significant reduction in annualized asthma exacerbation rates. This real-world evidence supports the effectiveness of these medications even in individuals with higher BMIs.

Researchers also explored whether adjusting eosinophil criteria – a biomarker used to determine eligibility for certain biologics – based on obesity could expand access to treatment. Currently, a threshold of ≥300 eosinophils/µL is commonly used. The study tested a lower threshold of ≥96 cells/µL, adjusted for obesity. While this approach increased the number of eligible patients by 11.3%, exploratory analyses didn’t present a clear benefit in exacerbation rates from the additional patients identified. This suggests that simply lowering the biomarker threshold may not be the answer and that further research is needed to understand how best to interpret biomarkers in the context of obesity-associated asthma. Corticosteroid insensitivity in obese asthma is a complex issue requiring nuanced approaches.

What Does This Mean for Patients?

These findings emphasize the importance of a proactive approach to asthma management, particularly for individuals with overweight or obesity. If you are struggling to control your asthma symptoms, even with standard treatments, it’s crucial to discuss your concerns with your healthcare provider. Don’t hesitate to ask if you might be a candidate for biologic therapy, and if a referral to a specialist is appropriate.

It’s critical to remember that asthma is a heterogeneous condition, meaning it manifests differently in different people. Obesity can alter the way the body responds to asthma medications, making it more difficult to achieve control. Biologics offer a targeted approach that can overcome some of these challenges, but access remains a significant hurdle.

Understanding Asthma Exacerbations and Biologics

An asthma exacerbation, often called an asthma attack, is a sudden worsening of asthma symptoms, including wheezing, coughing, chest tightness, and shortness of breath. These events can range from mild to life-threatening and often require emergency medical care. Biologics function by targeting specific molecules involved in the inflammatory pathways that drive asthma exacerbations. Different biologics target different pathways, making it important to identify the underlying cause of a patient’s asthma to select the most appropriate treatment.

The Role of Inflammation and Corticosteroid Resistance

Chronic inflammation plays a central role in asthma. Corticosteroids are typically the first-line treatment for asthma because they effectively suppress inflammation. However, in some patients, particularly those with obesity, the body becomes resistant to the effects of corticosteroids. This resistance can be due to a variety of factors, including changes in glucocorticoid receptor signaling and increased levels of inflammatory molecules. Corticosteroid pharmacokinetic abnormalities are more common in overweight and obese patients.

What’s Next: Improving Access and Refining Biomarker Use

The study authors emphasize the need for a multi-pronged approach to address the underutilization of respiratory biologics in obese asthma patients. This includes improving awareness among healthcare providers about the benefits of biologics, streamlining referral pathways to specialists, and addressing potential barriers to access, such as insurance coverage and cost. Further research is also needed to refine biomarker criteria and identify the optimal approach to selecting patients who will benefit most from these therapies. Ongoing clinical trials and real-world data analysis will continue to inform best practices in asthma management and ensure that all eligible patients have access to the most effective treatments available. The American Journal of Respiratory and Critical Care Medicine will publish further research on this topic in the coming months.