[Epidemiology of COPD in Japan].

The prevalence of COPD in Japan is revealed to be 8.6 % which is almost the same as foreign countries. However, there are many undiagnosed COPD patients. More than half of undiagnosed COPD patients go regularly to medical institution with other diseases. Among the patients who are 40 or more and go clinics with non-respiratory diseases, the prevalence of COPD is 8.6 to 10.3 %. If they have smoking history or some respiratory symptoms, the prevalence of COPD is 22 %. In Japanese reports, atherosclerosis is detected in 73.8 % of COPD patients, and the prevalence of COPD is high in heart failure, ischemic heart failure and liver diseases. The effort to decrease the mortality of COPD in Japan is necessary.