The Epidemiology of Pulmonary Nontuberculous Mycobacterial Disease in Japan

Abstract

Rationale: In recent years, the number of pulmonary nontuberculous mycobacterial (PNTM) disease has been expected to be increasing in Japan. The latest epidemiological survey conducted in 2007 using the previous criteria showed that the incidence of PNTM was calculated to be 5.7 cases per 100,000 person-years by comparing the ratio of PNTM and pulmonary tuberculosis (PTB) patients. Therefore, the precise updated data has been urgently required. Methods: In 2014, questionnaires were sent to 884 Japanese hospitals with respiratory departments certified by the Japanese Respiratory Society to collect the number of newly diagnosed patients from January to March 2014. PNTM disease was diagnosed according to the 2007 ATS/IDSA guideline. The incidence of PNTM was estimated by referring to that of patients with PTB. Results: Of the 884 hospitals, 551 institutions (62.3%) returned questionnaires with information. While the number of newly diagnosed PTB disease during the period is 2327 cases, that of newly diagnosed of PNTM disease is 2652 cases. Since the incidence of PTB disease is 12.9 cases per 100,000 person-years, that of PNTM disease is estimated to be 14.7 cases per 100,000 person-years. Pulmonary MAC comprised 88.8% of PNTM. The incidence of pulmonary M. kansasii disease is 0.6 cases per 100,000 person-years and that of M. abscessus is 0.5 cases per 100,000 person-years. Conclusion: We conducted the first nationwide epidemiological surveillance using the 2007 ATS/IDSA guideline. In Japan, the incidence of PNTM disease is estimated to be 14.7 cases per 100,000 person-years, which exceeds that of PTB disease. In 7 years, the incidence of PNTM disease has increased 2.6 times.