Does Body Weight Influence Asthma Therapy Results?

New research indicates overweight patients may have worse asthma control outcomes after a year of subcutaneous immunotherapy than their normal weight counterparts.

The very first study to consider the effects of patients’ weight on subcutaneous immunotherapy (SCIT) for asthma found that overweight patients may need greater dosage rates.

In data reported this month at the 2018 American Academy of Allergy, Asthma & Immunology (AAAAI) Congress in Orlando, FL, a team of New York-based researchers found that symptoms of asthma were significantly improved in patients of a normal weight group compared to an overweight patient group, when treated with the same dosage of SCIT therapies.

Led by Roshini Kuriakose, MD, of the Department of Medicine at Donald and Barbara Zucker School of Medicine at Hofstra Northwell, Mahasset, NY, the researchers conducted a retrospective chart review of 43 eligible patients with allergic asthma who were undergoing SCIT therapy.

Patients were categorized into groups by being either being underweight or normal weight (NW) or overweight/obese (OW). Adult participants were categorized based on body mass index (BMI) while children participants were categorized by weight category.

There were 24 (55.8%) patients categorized as NW, and 19 (44.2%) categorized as OW. NW patients were generally younger (mean age 18.1 years), female (66.7%), and had a lesser average amount of allergen sensitizations (4.9, versus 5.6). Though a majority of OW patients were also female (57.9%), the patient group was notably older (27.9 years).

Researchers measured asthma outcomes by changes in asthma control test (ACT) scores, spirometry parameters (FEV1; FEV1/FCV), and inhaled corticosteroid (ICS) dosage. Scores were logged at baseline and following 1 year of SCIT therapy.

At 1 year, NW patients reported greater improvements in FEV1 scores with 4.5% (95% CI; -2.0 — 7.0; P = .9092) than OW patients at 1% (95% CI; -9.0 — 19.0; P = .9092). Their FEV1/FVC score also improved by 3% at 1 year (95% CI; 0.0 — 5.0; P = .0185), while OW patient scores worsened by 1.5% (95% CI; -7.0 — 1.0; P = .0185).

Researchers found there was no association between changes in ICS dosage and patient weight categories, though OW patients have notably decreased improvements in asthma parameters when compared to their NW counterparts.

Kuriakose told MD Magazine that, despite previous research into the role of BMI and body weight in therapy, asthma is often associated with the worst outcome coming from patients who are obese. She said that physicians are often concerned of what upping the dosage for an OW patient with asthma would mean in adverse effects.

“Patients who have a higher dose might respond a little differently and have adverse reactions versus patients on lower dosage, so that is a concern,” Kuriakose said. “But there’s never been related studies that compare BMI categories.”

Kuriakose noted the field still lacks data as to how different dosages may affect patients in different BMI categories, which would make for an important post-study analysis. Future work in the field should particularly include a larger sample size, she said.

As approximately 30% of the 300 million people who are affected by asthma worldwide do not achieve optimal control of the condition, Kuriakose prosed there should be more consideration into how body weight influences the therapy process.

“We always give everyone who is obese or overweight the same dosage as someone who’s underweight or normal weight,” Kuriakose said. “Maybe patients who are overweight or obese might actually benefit from a higher dosage.”

The study, "The Effectiveness Of Immunotherapy For Allergic Asthma Among Different Weight Categories," was published online in the Journal of Allergy and Clinical Immunology last month.

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