HealthDay News — Obese patients with asthma have higher neutrophil counts and a reduced response to corticosteroid treatment compared to their lean counterparts, study results indicate. 

Obese patients experienced significantly lower corticosteroid-induced improvement on forced expiratory volume after two weeks of treatment  compared with lean patients (median 1.7% vs. 6.3%; P = 0.04), Eef D. Telenga, MD, from the University of Groningen in the Netherlands and colleagues reported in Allergy.

They conducted a study involving 63 obese and 213 lean asthma patients from four cohorts to determine whether severe airway obstruction and airway hyper-responsiveness differed between the two groups. Telenga and colleagues also examined the influence of obesity on the response to corticosteroid treatment in 118 patients. At baseline, asthma severity was comparable between the groups.

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Significantly higher blood neutrophil counts were seen in obese patients, specifically in obese women, but not obese men. There was a significantly lower improvement in the percentage of sputum eosinophils (P = 0.03) with increased BMI, and a smaller improvement in blood neutrophil counts in obese vs. lean patients (0.32 x103/μl vs 0.57 x103/μl, P = 0.046).

“The results of our study show that obese asthma patients have a distinct phenotype of asthma that is characterized by a higher level of neutrophilic inflammation in sputum and blood. Especially, obese female asthma [patients] show this increased neutrophilic inflammation,” the researchers wrote. “The increased neutrophilic inflammation may help to explain why obese asthma patients respond less to corticosteroid treatment.”

Several researchers disclosed financial ties to pharmaceutical companies, including GlaxoSmithKline, which funded two of the cohorts in this study.

Telenga ED et al. Allergy. 2012; doi:10.1111/j.1398-9995.2012.02855.x.