Venous thromboembolism in the Chinese population--experience in a regional hospital in Hong Kong.

OBJECTIVE: To estimate the incidence and determine the characteristic features of venous thromboembolism in the Hong Kong Chinese population.

DESIGN: Retrospective study.

SETTING: Regional hospital, Hong Kong.

SUBJECTS AND METHODS: Data were collected during a period of four years (1997-2000). Patients with duplex doppler ultrasonography or venography-documented venous thromboembolism and new episodes of deep vein thrombosis were identified from Department of Diagnostic Radiology records. Patients with high-probability ventilation-perfusion scans were identified from Department of Nuclear Medicine records and these scans were taken as evidence of pulmonary embolism. Patients with intermediate-probability ventilation-perfusion scans, with pulmonary embolism documented by either pulmonary angiography or spiral computed tomography scan, were also included in the study. Patients with autopsy-verified fatal pulmonary embolism were identified from Department of Pathology records. Patients with deep vein thrombosis at other sites were sought from patient discharge diagnostic coding data. Medical records were reviewed for patient characteristics and conditions associated with the development of venous thromboembolism.

RESULTS: Three hundred and seventy-six Chinese patients had venous thromboembolism during the study period. Of these, 352 had peripheral deep vein thrombosis, five had deep vein thrombosis at other sites (cerebral sinus and portal vein thrombosis), 40 had pulmonary embolism (26 had concomitant deep vein thrombosis), and six had fatal pulmonary embolism shown at autopsy.

CONCLUSION: The calculated annual incidence of venous thromboembolism in Hong Kong Chinese people was estimated at 16.6 events per 100,000 population, which is lower than incidence rates reported in Caucasians. The four conditions most commonly associated with venous thromboembolism were medical illness, malignancy, orthopaedic surgery, and intravenous drug use. Conditions associated with venous thromboembolism in patients younger than 45 years included intravenous drug use, thrombophilia, pregnancy, and the use of oral contraceptives.