Patterns of Health Risk: Influences on Quality of the Data

Indian Health Service Data

The primary source for American Indian health data is the Indian Health Service. This information is collected only from eligible (tribally enrolled, living on-or-near reservation of federally recognized tribes) members, who actually utilize IHS services. Therefore, IHS data may reflect “availability of services” rather than incidence and prevalence of illness, and may not include most of the 62% of American Indian who live off-reservation. (AoA, US DHHS, et al, 1996) Some American Indian elders who live off-reservation are able to utilize IHS services, sometimes traveling long distances to do so.

Mortality: Misidentification and Misclassification

Mortality for American Indian may be underestimated by 10% due to errors of misidentification of the race of the decedent, and/or misclassification in the cause of death (John, 1999, pg 71).

Regional Variability

Prevalence rates vary widely, especially in IHS data, from service area to service area and by tribal affiliation. For example, in 1998, 49.5% of adult Pima Indians (Arizona) had diabetes mellitus, and the Oklahoma Cherokee had 20.2% (McCabe & Cuellar, 1994, pg. 21). Higher prevalence of hypertension (31%) was reported by urban American Indians in Los Angeles than a national sample of elderly American Indian (19%) (Kramer, 1991; Los Angeles Co. AAA, 1989).