Prevalence of venous thromboembolism at a teaching hospital in Okinawa, Japan.

Limited data suggest that Asian Americans may have a lower risk of venous thromboembolism (VTE) than Caucasians. However, the actual prevalence of VTE among Asians remains controversial, and has not been described in Japan. We studied all 131,060 patients hospitalized at a single medical centre in Japan (January 1987 - December 1999). Patients with VTE were identified through discharge diagnoses. Hospital records were reviewed for information on patient demographics, risk factors, and diagnostic modalities. VTE occurred in 0.11% of admissions (n=141, 95%CI 0.09-0.13%). Mean age (+/-SD) was 64+/-17 years, 70% were women, 91% had deep vein thrombosis, and 29% pulmonary embolism. Among hospitalized patients 50-69 years old, VTE was significantly more common among women than men (0.31% vs. 0.08%; OR 3.88; 95%CI 1.45-6.31). We found a low prevalence of VTE in Japan compared to that reported in the US. Future studies are needed to clarify the reasons for our findings.