AIDS cases are reported to CDC by all 50 states, the District of Columbia, U.S. dependencies and possessions, and independent nations in free association with the United States¹ by use of a uniform case definition and case surveillance report form. This supplemental report includes cases reported according to the CDC guidelines for AIDS case surveillance and the case definition in effect at the time of their report; all cases meet the 1993 expanded surveillance case definition (MMWR 1992;41 [RR-17]:1-190).

This report presents the number of AIDS cases reported during and through 2000, the AIDS rate (cases per 100,000 population) for 2000, and estimated AIDS prevalence at the end of 2000 in adults and adolescents, by area of residence at AIDS diagnosis. Rank refers to the number assigned to a State or MSA according to the magnitude of the above measure, without consideration for the distance between the values (1). The lowest rank was assigned to the highest value of the measure. Ties were resolved by assigning the smallest of the corresponding ranks using SAS rank procedure (2). Because rank indicates a relative position with a series, a rank value is influenced by fluctuations associated with the corresponding State or MSA as well as those of the other sites in the series. Values of 0 were not assigned a rank.

Tables 5-8 present data for metropolitan statistical areas (MSAs) with a census 2000 population of 500,000 or more. The MSAs are defined by the Office of Management and Budget and were most recently updated in June 1998. Information is available at www.census.gov/population/www/
estimates/metrodef.html. The 6 New England states use New England County Metropolitan Area definitions instead of MSA.

Data in this report were compiled from cases reported to CDC through June 2001. Tables 1-3 and 5-7, present the number of AIDS cases reported to CDC either during 2000 or cumulatively from 1981 through 2000, and the AIDS rate (cases per 100,000 population) for adults and adolescents. AIDS prevalence was estimated by statistically adjusting data for delays in the reporting of cases and deaths. In tables 4 and 8, incidence and prevalence estimates are presented for cases diagnosed through December 2000. These estimates are not actual counts of cases reported to the surveillance system, but are based on reported cases adjusted for reporting delays. Risk for cases initially reported without exposure information has been statistically redistributed among the exposure categories based on historical patterns of reclassification. These estimates were calculated using the best methods available, yet include some inherent uncertainty. Small numbers should be interpreted with caution because the inherent uncertainty in estimates is greater for small numbers.

AIDS rates presented in tables 1 and 5 were calculated using population denominators based on official postcensus estimates and census 2000 counts from the U.S. Bureau of Census. Denominators for Guam, Puerto Rico and the U.S. Virgin Islands were based on official postcensus estimates from the U.S. Bureau of the Census International Database.

Statistical estimates for AIDS cases in 2000 among persons exposed through hemophilia/coagulation disorders or receipt of blood transfusion, blood components, or tissue are not presented. The relatively small number of cases in these categories in recent years does not provide information that results in accurate annual estimates; only cumulative estimates are presented. In table 8, estimates are presented only for exposure categories that have large enough numbers at the MSA level.

References

1. Colton T. Statistics in medicine. First edition. 1974. Little, Brown and Company, Boston, MA. Page 14.
2. SAS Institute Inc., SAS Online Documentation, Version 8, Cary, NC: SAS Institute Inc. 1999

¹Data are presented for the 50 states, the District of Columbia, Guam, the U.S. Pacific Islands, Puerto Rico, and the U.S. Virgin Islands. The U.S. Pacific Islands include American Samoa, the Republic of Palau, the Republic of the Marshall Islands, the Commonwealth of the Northern Mariana Islands, and the Federated States of Micronesia.