Introduction:

The study of reversibility to bronchodilators is part of the definition of asthma and COPD. Hence the importance attributed and the continuous search for the ideal definition.

This study aimed to compare the percentage of significant response to bronchodilators according to different definitions of ATS/ERS

Method: we conducted a retrospective comparative study at the pulmonology department including patients followed for obstructive disease. Spirometry was performed with a collection of forced expiratory volume in the first second and forced vital capacity before and after inhalation of 400 ug of Salbutamol. Reversibility was defined according to ATS/ERS2022: increase in FEV1 and/or FVC of more than 10% of the predicted value and the definition ATS/ERS 2015 was an increase in (FEV1 post - FEV1 pre) / FEV1 post >12% and increase in FEV1 >200ml in asthmatics and COPD patients.

Results= we enrolled 54 patients with asthma and 36 patients with COPD. The average age for asthmatics was 49 years and 60 for COPD. Patients with asthma were predominantly female.COPD patients were Predominantly male. Reversibility was noticed among 20% of COPD patients with ATS/ERS 2015  and with 11.4% with ATS/ERS 2022. The reversibility rate was the same among asthmatic patients with the ATS/ERS 2015 and 2022 definitions(15 %).The reversibility rate for patients with asthma and COPD according to the ATS/ERS 2022 definition was significantly lower than that obtained by applying the old ATS/ERS definition(% vs %p ; p<0,001).

Conclusion :

The new definition of reversibility is stricter despite a lower threshold for positivity. Given the small sample size, further studies are needed to support the finding on a larger sample