Background: There is currently disagreement on the way of expressing the reversibility of airflow obstruction, with some evaluations based on the initial FEV(1) while others use predicted FEV(1) (according to age, gender and height).
Objectives: To test the relevance of expressing bronchodilator response as a percentage of predicted FEV(1), we evaluated the influence of morphological data on the response to bronchodilators in a population with a large range of predicted values.
Methods: We measured the change in FEV(1) after inhalation of 200 microg of salbutamol in 30 asthmatic subjects (15 adults and 15 children) in whom predicted FEV(1) ranged between 1.13 and 4.10 liters and analyzed the respective influence of initial and predicted FEV(1 )on bronchodilator response.
Results: We have shown a significant relationship between the absolute variation in FEV(1), in liters, and predicted FEV(1) (p = 0.0019). There was also a significant relationship between the absolute variation in FEV(1) and initial FEV(1), in liters (p = 0.02). This relationship was no longer significant (p = 0.8) when the variation and initial FEV(1) were both expressed as percentages of predicted FEV(1). In addition, multiple regression analysis showed that predicted FEV(1) was the only independent variable correlating with the response to bronchodilators.
Conclusion: This study showed the influence of predicted FEV(1) on bronchodilator response. This result provides an additional argument for expressing bronchodilator response as a percentage of predicted FEV(1).
Copyright 2003 S. Karger AG, Basel