Declining incidence of AIDS and increasing prevalence of AIDS presenters among AIDS patients in Italy.

Presented here are the results of a cohort study conducted on 3,483 consecutive HIV/AIDS patients between January 1993 and December 2000 to determine trends in AIDS incidence and presentation. The incidence of AIDS was calculated in the general population and examined further according to gender, age (< or = or >49 years), and heterosexual behaviour as a risk factor for HIV. Multivariate analysis was used to identify variables associated with AIDS presenters (defined as patients diagnosed with AIDS within 1 month of the first HIV-positive test). The numbers of patients with AIDS classified as (i) AIDS presenters, (ii) known HIV-positive patients on antiretroviral treatment, and (iii) known HIV-positive patients not receiving antiretroviral treatment were calculated. The overall incidence of AIDS decreased over time, mainly due to the lower number of patients on antiretroviral treatment developing AIDS. Factors associated with a higher risk of being an AIDS presenter were male gender and year of HIV diagnosis. Among patients with AIDS, the proportion of AIDS presenters increased from 13.8% prior to 1997 (when protease inhibitors were introduced in Italy) to 32.5% after 1997. Variables predictive of being an AIDS presenter were male gender, age at diagnosis, and AIDS diagnosis in the years 1997-2000. Heterosexuals had a higher risk of being AIDS presenters and a lower risk of being HIV-positive and not receiving antiretroviral treatment than intravenous drug users. In Italy, AIDS occurs mainly in subjects unaware of their HIV status (especially males, the elderly, and those infected heterosexually) or in patients refusing antiretroviral therapy (mainly intravenous drug users who do not refer to specialised centres).