Racial misclassification of American Indians in Oklahoma State surveillance data for sexually transmitted diseases

The burden of sexually transmitted diseases (STDs) is high in American Indian/Alaska Native (AI/AN) populations. In addition, race is often misclassified in surveillance data. This study examined potential racial misclassification of American Indians in STD surveillance data in Oklahoma. Oklahoma State STD surveillance data for 1995 were matched with the Oklahoma State Indian Health Service Patient Registry to determine the number of AI/AN women who had one of three STDs but were not listed in Oklahoma surveillance data as AI/AN. Accounting for racial misclassification increased the rate of chlamydia for AI/AN women in Oklahoma by 32% (342/100,000 vs. 452/100,000) in the overall population. For gonorrhea, the rate increased by 57% (94/100,000 vs. 148/100,000) and for syphilis by 27% (15/100,000 vs. 19/100,000). Misclassified AI/AN women most often were classified as "White," and the likelihood of misclassification increased with a lower percentage of AI/AN ancestry. These findings indicate that STD rates may be underestimated for AI/AN populations nationwide. Racial misclassification in state surveillance data causes inaccuracies in characterizing the burden of infectious diseases in minorities.