Trends in HIV prevalence among public sexually transmitted disease clinic attendees in the Western region of the United States (1989-1999).

Objectives: Using data from anonymous unlinked testing of routinely collected sera, trends in HIV are compared among sexually transmitted disease patients in 4 Western urban centers.

Methods: Between 1989 and 1999, remnant sera obtained for routine syphilis testing from 256,819 patient visits to Denver, Los Angeles, San Francisco, and Seattle clinics were tested for HIV antibodies in an unlinked survey. HIV antibody test results were linked to anonymous demographic and risk information abstracted from the medical record.