SESSION TITLE: Physiology/PFTs/Rehabilitation Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PM
PURPOSE: Bronchodilator reversibility testing is recommended in all COPD patients but the reliability of the recommended response criteria and their relationship to disease progression has not been established. As bronchodilator responsiveness is a potential phenotypic characteristic of COPD, we studied the prevalence of a change in lung function after a bronchodilator in COPD patients.
METHODS: Patients with a clinical diagnosis and symptoms compatible with non-asthmatic COPD and met both the ERS and ATS spirometric criteria for this disorder were recruited from January 2011 to December 2012. Were aged 40-75 years and were current or ex-tobacco smokers. Spirometry was done before and after salbutamol. Responses were classified using the ATS (>12% of the baseline and 200 ml) and ERS criteria (>9% of the predicted FEV1).
RESULTS: 440 COPD patients ( 284 male, 62,2±9,7 years-old, FVC 82,1±19,5%, FEV1 60,2±19,8% and FEV1/FVC 59,1±12,1%). FEV1 and FVC increased significantly after inhaled salbutamol (mean change in FEV1 129,6±140 ml, in FVC 155,5± 232 ml and in the FEV1/FVC 1,32±3,1%). 165 (37,5%) were classified as responsive following the ERS criteria and 86 (19,5%) the ATS criteria. A 47,8% classified as responsive by ERS criteria were non-responsive by ATS criteria. The change in FEV1 expressed as an absolute value was not influenced by the pre-bronchodilator FEV1 in absolute units (r=0,007, p=0,889) but has a significant relationship with the baseline FEV1 as percentage of the initial value (r=0,36, p=0,001). Patients classified as responsive showed a lower baseline FEV1 (p=0,001) and a lower baseline FEV1/FVC (p=0,001).
CONCLUSIONS: Bronchodilating response even tested only after beta-agonists is not uncommon in COPD patients. The number of responders differs considerably according to the criterion used. In those defined by the absolute criterion as responders, there was no evidence that size of response was related to level of FEV1, but if expressed as percentage it is influenced by the baseline FEV1. Reversibility of airways obstruction in response to a bronchodilator is a continuous variable and not a dichotomous one.
CLINICAL IMPLICATIONS: Any cut off level of a "positive" bronchodilator response may be arbitrary.
DISCLOSURE: The following authors have nothing to disclose: Vanina Martín, Sebastian Lamot, Marco Solis, Josefina Villa, Nicolas Itcovici, Silvia Quadrelli
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