1 - Immunoallergy Department, Dona Estefânia Hospital, Centro Hospitalar Lisboa Central, Lisbon, Portugal

2 - CEDOC, Chronic Diseases Research Center, NOVA Medical School / Faculdade De Ciências Médicas, Universidade Nova De Lisboa, Lisbon, Portugal

**Divulgação**: Poster com discussão na Reunião da European Respiratory Society (ERS), Amesterdão, setembro de 2015

**Resumo**:

**Background:** The *Global Lung Function Initiative* (GLI 2012) proposed the use of unifying reference equations, based on the lower limit of normal (LLN).

**Aim**: To compare the theoretical values obtained through the GLI’s equations (Equation 1) and those obtained with Stanojevic all-ages reference equations (Equation 2) and determine the interpretative consequences of adopting the GLI’s regarding obstruction.**Methods: **192 individuals with physician diagnosed recurrent wheezing were evaluated through spirometry. A comparison of the theoretical values of the equations using the Bland-Altman’s analysis was performed. The considered bronchial obstruction criteria were FEVt<80% and FEVt<LLN. The agreement was studied through the Cohen’s Kappa coefficient (k).

**Results**: 59% of the individuals were males, mean age: 4.8 years old (SD:0.70). The mean differences between Equations 1 and 2 was 1.4% (±1.96SD: -3.5% to 0.6%) and -0.32% (±1.96SD: -1.0% to 0.3%) for FEV1 and FEV0.75, respectively. Regarding Equation 1: 22% had FEV1<80% and 20% <LLN; 27% had FEV0.75<80% and 27% <LLN. As far as Equation 2: 21% had FEV1<80% and 13% <LLN; 26 had FEV0.75<80% and 24% <LLN. Concerning the agreement between LLN /Fixed criteria for FEV1 and FEV0.75, the k was 0.93 and 0.96 (Equation 1) and 0.71 and 0.93 (Equation 2).

**Conclusions: **Adopting GLI instead of the Stajanovic equations influences mostly the interpretation of the FEV1, particularly when we consider the LLN criteria. Our results suggest that the use of the fixed criteria might be considered in the interpretation of the lung function tests.

**Palavras Chave: **Asma; Idade pré-escolar; Função respiratória