Methods. We analyzed data on Californians enrolled in Medicaid with an HIV/
AIDS diagnosis reported in 2007 Medicare or Medicaid claims data. We
compared alternative selection criteria by examining use of antiretroviral drugs,
HIV-specific monitoring tests, and medical costs. We compared the final sample
and average costs with other estimates of the size of California’s HIV/AIDS
population covered by Medicaid in 2007 and their average treatment costs.