What Is New In Small Airways Research
By Ves Dimov, M.D.
Allergist/Immunologist, Assistant Professor of Medicine and Pediatrics
University of Chicago
Web Content Editor, WAO Small Airways Working Group
Posted: 13 August 2012
Neutrophilic inflammation as a possible explanation for a reduced treatment response in obese patients with asthma
The incidence of asthma and obesity is increasing worldwide, and reports suggest that obese patients may have more severe asthma or reduced response to therapy. This study from the Netherlands included data from four asthma cohorts.
FEV(1), bronchial hyper-responsiveness PC(20) and sputum cell counts were comparable in 63 obese (BMI ≥30 kg/m[2)] and 213 lean patients (BMI <25 kg/m) at baseline. Female obese patients had significantly higher sputum and blood neutrophils.
After a two-week treatment with corticosteroids, there was less corticosteroid-induced improvement in FEV(1) in obese patients (median 1.7% vs 6.3% respectively, P = 0.04). The percentage of sputum eosinophils improved significantly less with higher BMI.
The smaller improvement in FEV(1) and sputum eosinophils suggests a worse corticosteroid treatment response in obese asthmatics.
Editor’s note: Previous studies of anti-IL-5 agents showed benefit only in some asthmatic patients with predominantly eosinophilic inflammation. As a future research avenue, it would be interesting to see if localized anti-neutrophilic therapies can bring improvement in obese patients with asthma.
Telenga ED, Tideman SW, Kerstjens HA, Hacken NH, Timens W, Postma DS, van den Berge M. Obesity in asthma: more neutrophilic inflammation as a possible explanation for a reduced treatment response. Allergy 2012; 67(8):1060-8.
Image source: Wikipedia, GNU Free Documentation License
Free ACT questionnaire may be superior to $3,000 FeNO device in determining asthma control in children
This study from Turkey included 76 children 6 to 11 years of age (mean age 8.7) with asthma who completed the Childhood Asthma Control Test (C-ACT) and underwent fractional concentration of exhaled nitric oxide (FeNO) and spirometric measurements during the monthly clinic visits.
A C-ACT score of 22 or less had 69% sensitivity and 77% specificity in determining not well-controlled asthma, whereas an FeNO value of 19 ppb or higher had 61% sensitivity and 59% specificity. Receiver operating characteristic curve analysis revealed that the C-ACT was better than FeNO for identifying patients with uncontrolled asthma.
A C-ACT score of 22 or less (odds ratio, 8.75) and an FeNO of 19 ppb or greater (odds ratio, 2.60) were indicators for uncontrolled asthma.
The authors concluded that C-ACT is superior to FeNO in determining the control status of children with asthma.
Editor’s note: Measurement of fractional concentration of exhaled nitric oxide (FeNO) has its place in the care of adults and children and is incorporated in the asthma guidelines (http://ajrccm.atsjournals.org/content/184/5/602.abstract). However, considering the cost of the device (for example, Niox Mino is priced above $3,000 in the U.S.), the use of a simple paper- or computer-based C-ACT score test has obvious cost-saving advantages. It is encouraging to have the scientific evidence that supports that this cost-saving approach can also be more accurate in children with asthma.
Yavuz ST, Civelek E, Sahiner UM, Buyuktiryaki AB, Tuncer A, Karabulut E, Sekerel BE. Identifying uncontrolled asthma in children with the childhood asthma control test or exhaled nitric oxide measurement. Annuals of Allergy Asthma and Immunology 2012; 109(1):36-40.
Relying on the symptom of wheeze to diagnose asthma in children may be an important cause of undertreatment
The diagnosis of asthma in younger children is difficult and based on clinical assessment of symptoms and results of physical examination. Respiratory wheeze has traditionally been used to define asthma in young children but there have been concerns that this definition is too narrow and may miss children with milder asthma who do not wheeze but have other symptoms such as cough or shortness of breath.
This study from Denmark included 411 children born to asthmatic mothers that were followed prospectively to age 7 years (313 had the full follow-up).
The total number of acute clinic visits for asthma symptoms was associated with later asthma (P < .0001), whereas the presence of wheeze at these visits was not (P = .5). The number of clinic visits for troublesome lung symptoms was also associated with later asthma in children who had never presented with any wheeze.
A quantitative global assessment of significant troublesome lung symptoms in the first 3 years of life is a better predictor of asthma than assessment of wheeze. Doctor-diagnosed wheeze is not a prerequisite for the diagnosis of asthma, and relying on the symptom of wheeze will likely be an important cause of undertreatment.
Editor’s note: The findings of this study are significant considering the widely used modified Asthma Predictive Index relies on 4 wheezing episodes during the past year (http://www.jacionline.org/article/S0091-6749(10)01034-1/abstract). Future predictive tools may need to incorporate symptoms other than wheezing to achieve better accuracy and clinical applicability.
Skytt N, Bønnelykke K, Bisgaard H. "To wheeze or not to wheeze": That is not the question. The Journal of Allergy and Clinical Immunology 2012; 130(2):403-407.e5.
Posted: 13 August 2012