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A3246 - Is Long-Term Clinical Course of Smokers Without Airflow Limitation (Former GOLD 0) Different from GOLD 1 or 2 ? An Analysis from the Hokkaido COPD Cohort Study
Author Block: N. Takei, M. Suzuki, H. Makita, S. Konno, K. Shimizu, H. Kimura, H. Kimura, M. Nishimura, the Hokkaido COPD Cohort Investigators; Department of Respiratory Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
RATIONALE: Long-term clinical course of smokers without persistent airflow limitation (i.e. former GOLD 0) has not been fully investigated. Recent studies have shown that symptomatic smokers with emphysema were associated with poor QOL, frequent exacerbations, and rapid decline in lung function, even if they had no airflow limitation (Prescott, NEJM 2016). Therefore, it is important to understand clinical course of smokers without persistent airflow limitation, especially in comparison with COPD patients with mild-to-moderate airflow limitation (GOLD 1-2). To investigate clinical characteristics and long-term clinical course of smokers without persistent airflow limitation (GOLD 0) in comparison with COPD patients with mild-to-moderate airflow limitation (GOLD 1-2), using data from a 10-year prospective observational cohort study.METHODS: We recruited 300 subjects suspected of COPD in the Hokkaido COPD study (Makita, Thorax 2007, Nishimura, AJRCCM 2012, Suzuki, AJRCCM 2016). Among them, 21 subjects did not meet the GOLD criteria for COPD during the first follow-up year (GOLD 0), while they came to seek medical care. 72 subjects were diagnosed as GOLD 1 and 126 as GOLD 2. We compared baseline characteristics and longitudinal clinical course, including annual change in FEV1 and exacerbation development during the first 5 years and mortality during the entire 10 years among all the subjects. RESULTS: The subjects with GOLD 0 had similar patient demographics compared to the subjects with GOLD 1, including pack-years, chronic bronchitis symptoms, CT emphysema score, and state of treatment. However, they had poorer QOL score than subjects with GOLD 1. Annual change in FEV1 during the first 5 years calculated using linear mixed effects models was significantly slower in the subjects with GOLD 0 compared to those with GOLD 1-2 (GOLD 0; 14.8 ml/year, GOLD 1; 29.6 ml/year, GOLD 2; 31.4 ml/year). On the other hand, time to first exacerbation during the first 5 years and all-cause mortality during the entire 10 years were not different in the subjects between GOLD 0 and GOLD 1-2. CONCLUSION; Although lung function decline in smokers without persistent airflow limitation was slower than in patients with mild to moderate COPD, exacerbations and mortality were comparable. We should pay more attention to clinical course of smokers without persistent airflow limitation who come to seek medical care.