Impact of using pre- and post-bronchodilator spirometry reference values in a Chinese population

<bold>Rationale:</bold> Spirometry reference equations that are derived from a large, nationally representative, general population are warranted in China and the impact of using pre- and post-BD spirometry reference values has yet to be assessed in Chinese populations. <bold>Objectives:</bold> To present both the pre-BD and post-BD spirometry reference values for Chinese adults using the China Pulmonary Health (CPH) study. <bold>Methods:</bold> A reference population of 12204 healthy, non-smoking participants in the CPH study was used to calculate the pre- and post-BD reference values for the forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC. Both pre- and post-BD reference values were applied to the entire CPH population (50991 individuals) to illustrate the divergence between the use of references in determining the disease prevalence and severity grading. <bold>Main Results:</bold> The prevalence of airflow limitation was 11.17% using pre-BD reference and 16.50% using the post-BD reference. Those that had been additionally identified as having airflow limitation based on the post-BD reference were found to have significantly higher rates of self-reported respiratory symptoms and significantly lower observed spirometry indicator values than those above the pre-BD reference. An additional 2.67% of participants were identified as grade II-IV COPD using the post-BD FEV1 reference. <bold>Conclusion:</bold> This study generated and applied pre- and post-bronchodilator spirometry reference values in a nationally representative Chinese adult population. Post-BD reference values may serve as an additional criterion in identifying individuals at risk for airway obstruction diseases.