Asthma and lower airway disease
Peripheral airway impairment measured by oscillometry predicts loss of asthma control in children

https://doi.org/10.1016/j.jaci.2012.09.022Get rights and content

Background

We previously showed that impulse oscillometry (IOS) indices of peripheral airway function are associated with asthma control in children. However, little data exist on whether dysfunction in the peripheral airways can predict loss of asthma control.

Objective

We sought to determine the utility of peripheral airway impairment, as measured by IOS, in predicting loss of asthma control in children.

Methods

Fifty-four children (age, 7-17 years) with controlled asthma were enrolled in the study. Spirometric and IOS indices of airway function were obtained at baseline and at a follow-up visit 8 to 12 weeks later. Physicians who were blinded to the IOS measurements assessed asthma control (National Asthma Education and Prevention Program guidelines) on both visits and prescribed no medication change between visits.

Results

Thirty-eight (70%) patients maintained asthma control between 2 visits (group C-C), and 16 patients had asthma that became uncontrolled on the follow-up visit (group C-UC). There was no difference in baseline spirometric results between the C-C and C-UC groups, except for FEV1/forced vital capacity ratio (86% vs 82%, respectively; P < .01). Baseline IOS results, including resistance of the respiratory system at 5 Hz (R5; 6.4 vs 4.3 cm H2O · L−1 · s), frequency dependence of resistance (difference of R5 and resistance of the respiratory system at 20 Hz [R5-20]; 2.0 vs 0.7 cm H2O · L−1 · s), and reactance area (13.1 vs 4.1 cm H2O · L−1), of group C-UC were significantly higher than those of group C-C (P < .01). Receiver operating characteristic analysis showed baseline R5-20 and reactance area effectively predicted asthma control status at the follow-up visit (area under the curve, 0.91 and 0.90).

Conclusion

Children with controlled asthma who have increased peripheral airway IOS indices are at risk of losing asthma control.

Section snippets

Methods

Children aged 7 to 17 years who were being actively treated for asthma by the Children’s Hospital of Orange County Breathmobile were enrolled in the study. The Breathmobile is a mobile asthma clinic that travels to schools in low-income neighborhoods throughout Orange County, California, and provides comprehensive asthma care to children. Children were included if they had a physician’s clinical diagnosis of mild-to-moderate asthma that was controlled according to the guidelines published by

Results

Fifty-four children with controlled asthma were consented for the study at the initial visit. On the basis of physicians’ assessments, 38 (70%) of these subjects continued to have controlled asthma, and 16 (30%) of these subjects lost asthma control on their follow-up visit. The demographics of the 2 groups are presented (Table I). The majority of our study population identified themselves as of Mexican descent, and the rest were a mixed ethnic population primarily of Caucasian and Asian

Discussion

Our study demonstrates that peripheral airway obstruction, as measured by IOS in a field clinical setting, was associated with future loss of asthma control in a pediatric population. Although asthma control was assessed by the physician independently of IOS, the cut points of peripheral airway IOS indices, including R5-20 and AX, were able to correctly classify up to 91% of our population. These findings suggest that IOS indices of peripheral airway function are useful in identifying asthmatic

References (35)

  • C.S. Farah et al.

    Obesity is a determinant of asthma control independent of inflammation and lung mechanics

    Chest

    (2011)
  • J. Frei et al.

    Impulse oscillometry: reference values in children 100 to 150 cm in height and 3 to 10 years of age

    Chest

    (2005)
  • E.D. Bateman et al.

    Global strategy for asthma management and prevention: GINA executive summary

    Eur Respir J

    (2008)
  • Expert Panel Report 3 (EPR-3): guidelines for the diagnosis and management of asthma—summary report 2007

    J Allergy Clin Immunol

    (2007)
  • From the Global Strategy for Asthma Management and Prevention, Global Initiative for Asthma (GINA) 2011. Available at:...
  • C. Kroegel

    Global Initiative for Asthma (GINA) guidelines: 15 years of application

    Expert Rev Clin Immunol

    (2009)
  • R.S. Gruchalla et al.

    Asthma morbidity among inner-city adolescents receiving guidelines-based therapy: role of predictors in the setting of high adherence

    J Allergy Clin Immunol

    (2009)
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    Supported by National Institutes of Health grant HL070645.

    Disclosure of potential conflict of interest: S. P. Galant has received research support from the University of California, Irvine. The rest of the authors declare that they have no relevant conflicts of interest.

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