Staging of airflow limitation according to GOLD, ERS/ATS, STAR and FEV1Q differ in relation to mortality

Different staging systems for the severity of airflow limitation in COPD have rarely been evaluated long-term based on annual spirometry measurements. <bold>Objective:</bold> To explore the association between different staging systems for airflow limitation and mortality based on annual spirometries during >10 years. The population-based OLIN COPD Study includes 993 adults with airflow obstruction (FEV1/FVC<0.70) and 993 age- and sex-matched referents (FEV1/FVC≥0.70) with repeated examinations from 2002-2004 until 2014, in total >11,000 spirometries. Severity staging by FEV1% predicted (GOLD), FEV1 z-score (ERS/ATS), FEV1/FVC ratio (STAR) and FEV1 in Litres (FEV1Q), was assessed at each examination, and used as time-varying covariates in Cox regression models estimating hazard ratios (HR) for association with 15-year mortality. The mean age was 65y at baseline and 55% were men. At baseline, 33% of the cases were current and 43% former smokers, compared to 13% and 40% among referents. The crude HR compared to referents were increased for GOLD and STAR stages 2, 3 and 4, while for ERS/ATS and FEV1Q, only stages 3 and 4. In general, adjustment for age, sex and height attenuated the results slightly (Figure 1). <bold>Conclusion:</bold> The four staging systems associated differently to mortality in relation to degree of airflow limitation. Staging according to GOLD seems to differentiate mortality most clearly between severity stages. <fig><object-id>erj;64/suppl_68/PA3098/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>