Incidence and characteristics of pulmonary thromboembolism in Japan 2000.

OBJECTIVE: The incidence of pulmonary thromboembolism (PTE) is much lower in Japan than in the United States. The number of deaths from PTE, however, has gradually increased. The present study was designed to investigate the incidence and characteristics of PTE in Japan.

METHODS AND MATERIALS: We sent 5,582 questionnaires to inquire about the number of new cases of PTE between August 1, 2000 and September 30, 2000.

RESULTS: We received 1,702 replies and 205 new cases were registered. The number of new cases per year was 4,022 (95% confidence interval: 3,704-4,305) and the incidence was 32 (95% confidence interval: 29.2-33.9) patients per 1,000,000 people per year. Main risk factors were immobilization, surgery, trauma, and malignancy. The mortality within a month and 6 months was 16% and 20%, respectively. Half of the deaths within a month occurred on the diagnosis day.

CONCLUSION: The results showed that the incidence of PTE in Japan 2000 tended to increase compared with that in 1996, but it was still much lower than that in the United States.