Spirometric criteria for asthma: Adding further evidence to the debate

Appleton, Sarah L.; Adams, Robert J.; Wilson, David H.; Taylor, Anne W.; Ruffin, Richard E.; on behalf of the North West Adelaide Cohort Health Study Team,

doi:10.1016/j.jaci.2005.08.034

« Previous Next »The Journal of Allergy and Clinical Immunology
Volume 116, Issue 5 , Pages 976-982, November 2005

Spirometric criteria for asthma: Adding further evidence to the debate

Sarah L. Appleton, BSc (Hons)
- From The Health Observatory, Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville
Robert J. Adams, MBBS, MD
- From The Health Observatory, Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville
- Reprint requests: Robert J. Adams, MBBS, MD, The Health Observatory, Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville Rd, Woodville, South Australia, 5011.
David H. Wilson, PhD
- From The Health Observatory, Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville
Anne W. Taylor, MPH
- Population Research and Outcome Studies Unit, South Australian Department of Health, Adelaide
Richard E. Ruffin, MBBS, MD
- From The Health Observatory, Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital Campus, Woodville
on behalf of the North West Adelaide Cohort Health Study Team

Received 29 March 2005; received in revised form 2 August 2005; accepted 18 August 2005.

Woodville and Adelaide, Australia

Background

Objective assessments of pulmonary function are considered essential for the diagnosis of asthma. The degree of reversibility of FEV₁ considered supportive of asthma varies between international asthma guidelines.

Objective

We sought to compare the relative performance of international guideline reversibility criteria for identifying impairment in persons with a significant bronchodilator response (SBR) without an asthma diagnosis.

Methods

The North West Adelaide Health (Cohort) Study, a population biomedical study of 4060 subjects, conducted spirometry according to American Thoracic Society criteria. SBR was defined as postbronchodilator FEV₁ responses of at least 12% or 15% of baseline values, 9% of predicted values, or 400 mL. A self-completed questionnaire assessed current asthma (CA), respiratory symptoms, and participant demographics.

Results

The prevalence of CA was 9.4% (n = 380), whereas 1.3% (≥400 mL) to 4.5% (≥9% of predicted value) of participants demonstrated an SBR in the absence of CA. With the exception of the 9% predicted criterion, prebronchodilator mean FEV₁ (percent predicted) in those demonstrating an SBR but no CA was significantly worse than that in the CA group. Significantly more respiratory symptoms were experienced by the SBR groups than the group without asthma. Logistic regression analyses identified different characteristics of those classified by the following criteria: 12% and 15%, age of 40 years or greater and household income of less than $40,000; 9% predicted, household income of less than $40,000; 400 mL, male sex (odds ratio, 4.5; 95% CI, 2.1-9.3).

Conclusions

Different criteria identify different persons, but SBR by any criteria was associated with significant respiratory impairment, some of which might be attributable to asthma. Postbronchodilator change as a percentage of predicted value was the least biased of the criteria.

Key words: Asthma, spirometry, bronchodilator response, asthma epidemiology, asthma diagnosis

Abbreviations used: BTS/SIGN, British Thoracic Society/Scottish Intercollegiate Guidelines Network, CA, Current confirmed asthma, CLD Index, Chronic Lung Disease Index, COPD, Chronic obstructive pulmonary disease, GINA, Global Initiative for Asthma, NICE, National Institute for Clinical Excellence, SBR, Significant bronchodilator response