High incidence of symptomatic venous thromboembolism in Thai hospitalized medical patients without thromboprophylaxis

Venous thromboembolism (VTE) is a common preventable cause of mortality during hospitalization. However, prophylaxis is frequently under-utilized due to the belief that it is rare in Asia. The objective of the study was to estimate the incidence of symptomatic VTE in hospitalized nonsurgical Thai patients. We performed a prospective study in medical wards in Chulalongkorn Hospital, a tertiary care university-based center, from June 2007 to December 2008. We included adult patients admitted beyond 3 days. Patients with VTE before admissions or undergoing major surgery during hospitalization were excluded. According to the usual practice, heparin prophylaxis was not given. However, the program of primary physician education and fast-track diagnostic imaging were implemented. Forty-two VTEs from 7126 susceptible patients [0.59%, 95% confidence interval (CI) 0.41-0.77%] were found; 20 (48%) definite pulmonary embolism, four of which also had symptomatic deep vein thrombosis (DVT), 19 (45%) definite DVT and three sudden deaths from possible pulmonary embolism. Immobilization (74%), active cancer (52%) and rheumatologic diseases (12%), including arthritis of lower extremities and systemic lupus erythematosus with antiphospholipid, were common VTE risk factors, which were present in our patients. The incidences in total cases of arthritis, cancer, mechanical ventilation and congestive heart failure were 7.7, 1.8, 1.5 and 0.5%, respectively. Notably, nine of 23 (39%) pulmonary embolism cases were fatal and two more patients (9.5%) expired from bleeding after treatment (one pulmonary embolism and one DVT). In conclusion, VTE contributes significant hazard to hospitalized nonsurgical Thai patients. Appropriate measures to assure proper thromboprophylaxis in high-risk patients are strongly needed.