@article {Kotti Maj USAF565, author = {George H Kotti Maj USAF and David G Bell and Tokunbo Matthews and Pedro F Lucero and Michael J Morris}, title = {Correlation of Airway Hyper-responsiveness With Obstructive Spirometric Indices and FEV1 > 90\% of Predicted}, volume = {57}, number = {4}, pages = {565--571}, year = {2012}, doi = {10.4187/respcare.01244}, publisher = {Respiratory Care}, abstract = {BACKGROUND: Current published guidelines on spirometry interpretation suggest an elevated FVC and FEV1 \> 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: FEV1 \> 90\% of predicted, and FEV1/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 FEV1 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 FEV1 \< 100\%, when compared to patients with an FEV1 >= 100\%. CONCLUSIONS: A normal FEV1 \> 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 FEV1 is \> 90\% of predicted.}, issn = {0020-1324}, URL = {https://rc.rcjournal.com/content/57/4/565}, eprint = {https://rc.rcjournal.com/content/57/4/565.full.pdf}, journal = {Respiratory Care} }