PT  - JOURNAL ARTICLE
AU  - Kitazawa, Haruna
AU  - Jiang, Annie
AU  - Nohra, Cynthia
AU  - Ota, Honami
AU  - Wu, Joyce K Y
AU  - Ryan, Clodagh M
AU  - Chow, Chung-Wai
TI  - Changes in interpretation of spirometry by implementing the GLI 2012 reference equations: impact on patients tested in a hospital-based PFT lab in a large metropolitan city
AID  - 10.1136/bmjresp-2022-001389
DP  - 2022 Dec 01
TA  - BMJ Open Respiratory Research
PG  - e001389
VI  - 9
IP  - 1
4099  - http://bmjopenrespres.bmj.com/content/9/1/e001389.short
4100  - http://bmjopenrespres.bmj.com/content/9/1/e001389.full
SO  - BMJ Open Resp Res2022 Dec 01; 9
AB  - Background The Global Lung Function Initiative (GLI-2012) focused on race/ethnicity as an important factor in determining reference values. This study evaluated the effects of changing from Canadian reference equations developed from an all-Caucasian cohort with European ancestry to the GLI-2012 on the interpretation of spirometry in a multiethnic population and aimed to identify the ethnic groups affected by discrepant interpretations.Methods Clinically indicated spirometry in a multiethnic population (aged 20–80 years) collected from 2018 to 2021 was analysed. The predicted and lower limit of normal (LLN) values were calculated using three sets of reference equations: Canadian, GLI-race/ethnic-based (GLI-Race) and GLI-race/ethnic-neutral (GLI-Other). We compared the prevalence of concordance in the abnormal diagnoses (defined as <LLN) for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/FVC among the three reference values, and evaluated whether race/ethnicity was associated with discordance.Results Data from 406 participants were evaluated (non-Caucasian 43.6%). There was 85%–87% concordance for normal/abnormal FVC and FEV1 interpretations among the Canadian, GLI-Race and GLI-Other reference equations. In all ethnic groups, application of the Canadian references for interpretation led to a higher prevalence of abnormal (<LLN) FVC and FEV1compared with GLI-Race and GLI-Other. This trend was more prominent in Black, South-East Asian and Mixed/other ethnic groups when comparing the Canadian to the GLI-Race equations. In contrast, the discordance rates were similar among ethnic groups when compared with the GLI-Other reference equations. Interpretation of FEV1/FVC had a high rate of agreement among all equations.Conclusion Interpretation using Canadian reference equations was associated with a higher prevalence of restrictive physiology compared with the GLI-2012 equations, particularly if the GLI-Race were used. These observations were mostly found in non-white Caucasian groups, highlighting the need to choose reference equations that reflect closely the ethnic mix of the population being evaluated in order to optimise patient management.Data are available upon reasonable request. Data will be made available on request after review and approval by the respective institutions where the data are gathered and stored.