Correlation of airway hyper-responsiveness with obstructive spirometric indices and FEV 1 > 90% of predicted

George H. Kotti, David G. Bell, Tokunbo Matthews, Pedro F. Lucero, Michael J. Morris

Research output: Contribution to journalReview articlepeer-review

3 Scopus citations

Abstract

BACKGROUND: Current published guidelines on spirometry interpretation suggest an elevated FVC and FEV 1 > 100% of predicted with an obstructive ratio may represent a physiological variant. There is minimal evidence whether this finding can be indicative of symptomatic airways obstruction. METHODS: Pulmonary function testing databases for a 4-year period were retrospectively reviewed. All technically adequate spirometry studies were included, based on these criteria: FEV 1 > 90% of predicted, and FEV 1/FVC below the lower limit of normal, based on 95th percentile confidence intervals. Clinical indications for testing were noted. Testing for post-bronchodilator response, lung volumes, and methacholine challenge tests were reviewed for evidence of airway hyper-responsiveness (AHR). Comparisons were made between symptomatic versus asymptomatic individuals and FEV 1 values less than or greater than 100% of predicted. RESULTS: A total of 280 studies were analyzed. During their clinical evaluation, 192 patients (69%) had post-bronchodilator spirometry recorded, 63 patients (23%) had lung volumes, and 36 patients (11%) completed methacholine challenge testing. Indications for spirometry included 193 symptomatic patients and 87 asymptomatic patients. Nearly 28% of patients with post-bronchodilator testing met criteria for AHR. No differences in AHR were found between the symptomatic and asymptomatic groups. The majority of patients (77%) with AHR had an FEV 1 < 100%, when compared to patients with an FEV 1 ≥ 100%. CONCLUSIONS: A normal FEV 1 > 90% of predicted with obstructive indices may not represent a normal physiological variant, as 28% of patients were found to have underlying AHR. These findings suggest that clinicians should evaluate for AHR, especially in symptomatic patients, even if the FEV 1 is > 90% of predicted.

Original languageEnglish
Pages (from-to)565-571
Number of pages7
JournalRespiratory Care
Volume57
Issue number4
DOIs
StatePublished - Apr 2012
Externally publishedYes

Keywords

  • Airway hyper-responsiveness
  • Normal FEV
  • Obstruction
  • Pulmonary function testing

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