Pulmonary thromboembolism in American Indians and Alaskan natives

Background: The rate of diagnosis of deep venous thrombosis and/or pulmonary embolism (collectively, venous thromboembolism: VTE) among patients discharged from Indian Health Service hospital care from 1980 through 1996 was considerably lower than rates reported in African Americans or whites. Expansion of the national census in 1990 to include American Indians and Alaskan Natives permits a more in-depth examination of this issue. Methods: Combined data from the National Hospital Discharge Survey (nonfederal hospitals) and the Indian Health Service (federal hospitals) from 1996 through 2001 were used to evaluate the rate of diagnosis of VTE in American Indians and Alaskan Natives. Results: The diagnosis of VTE in American Indians and Alaskan Natives, based on combined data from the National Hospital Discharge Survey and the Indian Health Service was 71 per 100000 per year compared with 155 per 100000 per year in African Americans (P<.001) and 131 per 100000 per year in whites (P<.001). The rate ratio comparing the rate of diagnosis of VTE in American Indians and Alaskan Natives with African Americans was 0.46 (95% confidence interval, 0.45-0.47) and comparing American Indians and Alaskan Natives with whites it was 0.54 (95% confidence interval, 0.53-0.55). Conclusions: The observed relatively low incidence of VTE in American Indians and Alaskan Natives would seem to be due to as yet undetermined genetic factors. The possibility that American Indians and Alaskan Natives have different lifestyles that affect the rate of diagnosis of VTE cannot be excluded.