First, let’s acknowledge these achievements in asthma management: Between 2001 and 2021, asthma-related hospitalizations, emergency department (ED) visits and number of attacks per patient have all declined.

But will these asthma-management achievements continue their downward course?

Excess weight is a known risk factor in causing asthma, and obesity prevalence — and overweight prevalence — remain problematic. Severe obesity, especially among women continues to rise; the overall rate of obesity in children goes in the same direction. People with obesity and asthma do not respond to typical asthma treatments, like corticosteroids, as well as those who do not have overweight. Their disease develops differently than in normal weight individuals. This diagram shows two asthma-obesity phenotypes: How obesity complicates existing asthma, and how asthma develops because of obesity.

Clifford W. Bassett, MD, clinical associate professor, NYU Grossman School of Medicine, with input from two colleagues from NYU Langone, Fannie Weng, MD, an internal medicine resident, and Anastasios Manessis, MD, an endocrinology/metabolism specialist, put together a quick reference guide for primary care physicians (PCPs) who treat patients with asthma and obesity.

Are obesity and pre-diabetes increasingly common in your asthma panel?

Yes. Each 1% A1c rise is linked to lower forced expiratory volume in 1 second (FEV₁) and more hospitalizations. Poor glucose control worsens asthma, while steroids worsen glucose metabolism. Physicians should track BMI and A1c at every visit.

What is some of the reasoning that asthma control may be harder in obesity?

From a mechanical vantage point, patients have reduced lung volumes and airway closure. The inflammation is cytokine-driven and steroid-resistant. And the comorbidities are significant. Obstructive sleep apnea, gastroesophageal reflux disease (GERD) and rhinosinusitis can be found in most patients: OSA, 40-90%; GERD, 60-75%, and rhinosinusitis, up to 80%.

Expect blunted inhaled corticosteroid effect, and respond by optimizing the device, step up earlier and consider biologics. Specialists you should consider in assembling are allergists (environment/immune therapies), pulmonologists (lung mechanics/severe asthma), endocrinology and registered dietitians (weight/metabolism), otorhinolaryngologists and gastroenterologists (airways/GERD).

When should I refer an adult with asthma and obesity to specialists?

Obesity-asthma is a distinct phenotype with reduced corticosteroid responsiveness. Collaborative, multidisciplinary care improves outcomes. Refer when asthma remains uncontrolled despite guideline-based therapy and correct inhaler use, when metabolic disease complicates management, or when advanced diagnostics are needed. Here are specialists to consider with these specific triggers:

• Pulmonology/Allergy: Two or more oral corticosteroids-treated exacerbations/year, daily or nocturnal short-acting beta-agonist use — phenotype refinement, biologics
• Allergy/Immunology: Environmental evaluation, allergy testing, immune-based therapies (biologics, immunotherapy in selected allergic asthma), co-management after ED/hospital visits
• Endocrinology: A1c over 7% despite treatment, GLP-1 consideration
• Registered dietitian: Nutrition counseling, structured weight programs, tailored activity
• Otorhinolaryngology: Chronic rhinosinusitis, nasal polyps, airway obstruction (up to 80%)
• Gastroenterology: Symptomatic/refractory GERD (60-75%)

A rundown to consider for expedited asthma specialist referral:

• Two or more ED visits or one or more hospitalizations in past year
• Two or more oral corticosteroid bursts in 6 months
• FEV₁ < 60% predicted
• A1c > 9% despite therapy
• Severe uncontrolled GERD or sinus disease
• Rapid weight gain with worsening asthma

How should physicians discuss weight with patients in a fast and effective manner?

Use motivational interviewing — link weight loss to asthma improvement. For example, try “Losing just 5-10% of your weight can improve asthma control, reduce flare-ups, and help your lungs work better.” Physicians can add weight goals to the asthma plan, refer early to registered dieticians to develop a weight-loss program. They also should involve endocrinology for GLP-1s, review every 3-6 months (may vary), and document counseling (~12.6% of visits).

Do treatment protocols change for patients with obese asthma?

The core guidelines apply, but the emphasis shifts.

• Monitoring and screening: Physicians need to monitor inhaler technique and home peak flow, and screen for sleep apnea, GERD, sinus irregularities, and vitamin D levels.
• Allergy/Immunology: Testing of environmental plans and immunotherapy in selected allergic asthma. Physicians should discuss improved patient monitoring techniques, that is, low-cost home electronic peak flow meters.
• Weight management: Consult endocrinologists and registered dietitians for metabolic care including GLP-1 use, activity plans and bariatric surgery when indicated.
• Multidisciplinary model: Physicians should consult with allergists and pulmonologists for severe disease; endocrinologists and registered dietitians for weight/metabolic optimization; otorhinolaryngologists and gastroenterologists for airway and reflux.

Do asthma and obesity cluster in families?

Yes — primarily because of their shared environment — diet, lifestyle, allergen exposure. Physicians should take a family history and provide anticipatory guidance that includes a healthy diet, physical activity and allergen reduction.

What are specialists sharing at recent conferences?

Much of what has been discussed in this article. For example, the importance of patient-specific collaboration across pulmonology, allergy, endocrinology, otorhinolaryngology, gastroenterology. Other discussions cover the unified airway — interaction of the nose and lungs. Specifically, treating rhinitis/sinusitis improves asthma. And conferences include discussion on emerging therapies, such as biologics, GLP-1s, bariatric surgery, and allergen immunotherapy in selected allergic asthma.

That said, there are also topics that need better coverage, such as weight counseling, allergy/environment, and delayed referrals. PCPs can fill these gaps by documenting weight and environment counseling, referring patients early when exacerbations or comorbidities complicate treatment, and building communication pathways with specialists.