Severe asthma: Comparison of different classifications of severity and control

Abstract Background Criteria of asthma severity and control lack standardization. Objective to compare classifications of asthma severity and control, applied to patients from a severe asthma clinic. Methods Cross-sectional study of 473 patients followed up for ≥6 months, reclassified using three criteria: 1) the World Health Organization (WHO) 2010, 2) the American Thoracic Society (ATS) 2000, and 3) the European Respiratory Society (ERS)/ATS 2014. In order to evaluate disease control, the 2012 and 2014 Global Initiative for Asthma (GINA) classifications were compared. Results According to the definition of WHO 2010, 429 had Difficult-to-treat severe asthma and only 12 presented Treatment-resistant severe asthma. 114 patients had Refractory asthma by ATS 2000 and 88 had Severe asthma by ERS/ATS 2014. Considering the definitions of WHO 2010, only 9 out of 12 with Treatment-resistant and 64 out of 429 with Difficult-to-treat severe asthma met the criteria of ATS 2000 and ERS/ATS 2014. As for GINA classification of control, 208 (44%) of the 473 subjects were classified as having asthma controlled by the 2014 criteria, whereas only 45 (10%) patients had controlled asthma by the GINA 2012 criteria. The Kappa statistic indicates the highest agreement of the severity classification occurred between the criteria of ATS 2000 and ERS/ATS 2014 (0.64). Conclusion Good agreement was found between Refractory asthma ATS 2000 and Severe asthma ERS/ATS 2014 classifications. However, poor agreement was observed between the severity rating proposed by the WHO and other classifications. The GINA control classifications of 2012 and 2014 also agreed poorly.