What Is New In Small Airways Research
By Ves Dimov, MD
Allergist/Immunologist, Assistant Professor, University of Chicago
Targeting small airways asthma phenotype: preserved FEV1 but abnormal midexpiratory flow and airway resistance
There is an unmet need in current asthma guidelines for those individuals who exhibit the small airways asthma phenotype with FEV1 but abnormal forced midexpiratory flow and peripheral airway resistance, which tends to be associated with poorer control. Extrafine hydrofluoroalkane solution formulations of inhaled corticosteroid either alone or in combination with long-acting beta-agonist may improve small airways outcomes and associated control.
From a pragmatic perspective, it makes sense to try to deliver asthma treatment to more of the lung to improve clinical outcomes, especially in patients who exhibit the small airways asthma phenotype.
It remains to be seen if this “pragmatic perspective” is confirmed by clinical trials.
Source: Lipworth B. Targeting the small airways asthma phenotype: if we can reach it, should we treat it? Annals of Allergy, Asthma & Immunology 2013; 110(4): 233-239.
Add-on omalizumab associated with decreased hospitalization or Emergency Department (ED) visits in patients with uncontrolled severe asthma in real-life practice
This longitudinal study in real-life settings included a cohort of 767 adults with uncontrolled severe asthma despite inhaled and oral corticosteroid and long-acting beta-agonist. From the initial group, 374 patients took omalizumab at least once (mean observation period, 20.4 months).
Omalizumab use was associated with a relative risk of 0.57 for hospitalization or ED visits for asthma. In users of omalizumab, the relative risk of hospitalization or ED visits for asthma during omalizumab treatment vs nontreatment periods was 0.40.
Add-on omalizumab was associated with a decreased risk of hospitalization or ED visits in patients with uncontrolled severe asthma in real-life practice.
There are limitations to the design of this study, specifically the inclusion criteria for taking omalizumab “at least once”. The cost of the medication is also a significant barrier in many countries.
Source: Lamiae Grimaldi-Bensouda L, Zureik M, Aubier M, Humbert M, Levy J et al, for the Pharmacoepidemiology of Asthma and Xolair (PAX) Study Group. Does Omalizumab make a difference to the real-life treatment of asthma exacerbations?: Results from a large cohort of patients with severe uncontrolled asthma. Chest. 2013; 143(2):398-405. doi:10.1378/chest.12-1372
Measurements of FENO may not be useful in elderly asthmatics
Fractional Exhaled Nitric Oxide (FENO) has been extensively studied in children and adults with asthma, but little is known about FENO in elderly asthmatics.
This study enrolled 30 stable asthmatics 65 years old and older were followed for one year with evaluations at baseline and every 3 months.
FENO was not elevated in our study subjects throughout the study period (mean level was below 30 ppb). No correlation was found between FENO and FEV1/FVC, inhaled steroid dose or Asthma Control Test (ACT) scores at any time point.
Moderate asthma exacerbations did not consistently cause an increase of FENO.
The authors concluded that routine measurements of FENO may not be clinically valuable in elderly asthmatics.
Purchasing a FENO measuring device is a significant expense and the cost of each single use sensor is in the range of $15 in the USA. If the findings of this study are confirmed, elderly patients with asthma may not need routine FENO monitoring, thus realizing savings for the patient and the health system.
Source: Columbo M, Wong B, Panettieri RA, Rohr AS. Asthma in the elderly: The role of exhaled nitric oxide measurements. Respiratory Medicine 2013; 107(5): 785-787.