Abstract
BACKGROUND: We conducted a prospective observational study to elucidate the long-term prognosis and management of chronic obstructive pulmonary disease (COPD) in clinical practice in Japan in the mid-2010s. METHODS: This prospective cohort study included 29 facilities. Data from 427 patients clinically diagnosed with COPD, enrolled between September 2013 and April 2016, were analyzed. Interstitial pneumonia was excluded through a central multidisciplinary discussion. Follow-up data were collected for up to 5 years after patient registration. RESULTS: At the time of registration, 53 patients clinically diagnosed with COPD did not have airflow limitation (AFL). In the cohort with AFL (n = 374), 232 patients completed a 5-year follow-up, while 49 patients died during the 1576.6 person-years of observation. The mean age was 71.7 years with an overall 5-year survival rate of 85.4%. Stratified by % forced expiratory volume in one second (FEV1), survival rates were 93.6% in the mild and moderate AFL group, 82.5% in the severe AFL group, and 66.1% in the very severe AFL group. The prognosis of the subpopulation without AFL was poor with a 5-year survival of 81.6%. This subpopulation exhibited respiratory symptoms, low vital capacity and total lung capacity, and emphysematous changes. CONCLUSIONS: Our study presents the 5-year survival and real-world clinical practice scenario of a prospective cohort of patients clinically diagnosed with COPD in Japan in the mid-2010s. The survival rates of our cohort were numerically better than the Japanese cohort in the 1990s, regardless of the high median age of this cohort. Overall, 12.4% of the patients in this cohort with no AFL at registration exhibited respiratory symptoms and distinct spirometric patterns, and had a poor prognosis.