Incidence of venous thromboembolism in different ethnic groups: a regional direct comparison study.

Liao, S; Woulfe, T; Hyder, S; Merriman, E; Simpson, D; Chunilal, S

BACKGROUND There are few studies that directly compare the variation in incidence of venous thromboembolism (VTE) according to ethnicity. OBJECTIVE The aim of this study was to compare the rates of VTE, deep venous thrombosis (DVT) and pulmonary embolism (PE) among different ethnic groups. METHOD The cases diagnosed with VTE, DVT and PE for a period between March 2004 and June 2009 were identified through the hospital-based database system. The 2006 New Zealand Census data were used to calculate the rate of diagnosis. RESULTS The observed annual incidence of VTE during this period was 81.6 per 100000 population. The relative risks of VTE when comparing European subjects with Maori, Pacific Island and Asian subjects after age standardization were 1.98 (95% confidence interval [CI], 1.63-2.41), 3.22 (95% CI, 2.60-3.99) and 4.02 (95% CI, 3.34-4.84), respectively. Relative risks of DVT after age standardization when comparing European subjects with Maori, Pacific Island and Asian subjects, were 2.14 (95% CI, 1.72-2.66), 3.20 (95% CI, 2.46-4.17) and 4.75 (95% CI, 3.80-5.94), respectively. Indirect age standardization was used for comparison of the diagnosis of PE. The ratio between the calculated expected number of cases and the actual number of cases was 1.32 (95% CI, 0.89-1.75) for Maori subjects, 2.96 (95% CI, 1.89-4.03) for Pacific Islanders and 3.89 (95% CI, 3.00-4.78) for Asians. CONCLUSION Europeans have a significantly higher incidence of VTE compared with Maori, Pacific Island and Asian populations.