SESSION TYPE: COPD: Diagnosis and Evaluation
PRESENTED ON: Sunday, October 21, 2012 at 01:15 PM - 02:45 PM
PURPOSE: Bronchodilators are the mainstay in therapy for obstructive lung disease. It is known that chronic obstructive lung disease tends not to be responsive to bronchodilators. This study aims to determine the prevalence of bronchodilator response within the US population as well as amongst those with obstructive physiology and to determine if bronchodilator responsiveness is dependent on prebronchodilator obstructive physiology.
METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2009 on spirometry and bronchodilator responsiveness was analyzed. Patients having spirometry and bronchodilator challenges were enrolled. Patients were categorized as having a bronchodilator response if either the forced expiratory volume in the first second (FEV1) or the forced vital capacity (FVC) increased by 12% or 200mL. Two methods to assess obstruction were used. An FEV1/FVC ratio of less than 70% and FEV1/FVC less than the lower limits of normal (LLN) as determined using limits from NHANES 3. Independence testing was calculated using the Fesher's Exacte test.
RESULTS: 1,107 patients met inclusion criteria. A total of 215 (19.4%) had a response to bronchodilators and a total of 692 (62.5%) had an FEV1FVC ratio less than 70% and 508 (45.8%) less than the LLN. No difference in response to bronchodilators exists in those with obstructive defects and those without when using a FEV1/FVC ratio of less than 70% (p=0.7537). When using the LLN, patients with obstruction were 2.9 times as likely to have a bronchodilator response than those without (30.1% vs 10.3%, p=0.0001).
CONCLUSIONS: Bronchodilator response is a phenomenon seen in only 30% of patients with obstruction when obstruction is measured using the LLN. All patients with obstructive physiology should have bronchodilator testing. The high prevalence of bronchodilator response suggests that patients presenting with shortness of breath - regardless of the presence of obstructive physiology - may benefit from bronchodilator testing. This study provides support for using LLN over a 70% cutoff for diagnosing obstruction.
CLINICAL IMPLICATIONS: The high prevalence of bronchodilator response and obstruction in the study population suggests that lung disease is likely underdiagnosed. While this does not address the utility of screening, it does show that greater awareness of lung disease is needed in the medical community.
DISCLOSURE: The following authors have nothing to disclose: Irtza Sharif, Pratick Patel, Jennifer LaRosa
No Product/Research Disclosure InformationNewark Beth Israel Medical Center, Newark, NJ