Patient ethnicity and use of venous thromboembolism prophylaxis.

OBJECTIVE: Patients at highest risk for developing venous thromboembolism include those undergoing major orthopedic surgery. However, physicians vary in their strategies to prevent venous thromboembolism. We evaluated whether the use of venous thromboembolism prophylaxis after orthopedic surgery is related to patient ethnicity. DESIGN: Retrospective cohort study, 1998-2002. SETTING: Tertiary care, university-affiliated hospital in Hawaii. STUDY PARTICIPANTS: 1811 adults (1085 women; 743 Asians; 206 Pacific Islanders; mean age 70.6 +/- 14.7 years) who underwent hip replacement, hip fracture surgery, or total knee replacement. MAIN OUTCOME MEASURES: Use of venous thromboembolism prophylaxis as recommended by the American College of Chest Physicians. Multivariable logistic regression was used to identify factors associated with prophylaxis use. RESULTS: Overall, 49.4% of patients received venous thromboembolism prophylaxis. After adjustment for patient age, sex, thromboembolism and bleeding risk factors, type of surgery, and anesthesia, Japanese patients were less likely to receive prophylaxis [odds ratio (OR) = 0.7; 95% confidence interval (CI) = 0.5-0.9; P = 0.01], whereas other ethnic groups were treated similarly to whites. Relative to patients undergoing hip replacement, those with hip fracture surgery were less likely (OR = 0.4; 95% CI = 0.3-0.5; P < 0.01), and those receiving total knee replacement more likely (OR = 4.5; 95% CI = 3.6-5.7; P < 0.01) to receive appropriate prophylaxis. CONCLUSION: Despite consensus recommendations, venous thromboembolism prophylaxis use among high-risk patients remains low. Japanese patients and those undergoing hip fracture surgery are at particular risk for not receiving appropriate prophylaxis in our population. Further research is needed to clarify the reasons for our findings and to determine if this variation is associated with increased risk of thromboembolic complications.