[Survival, progression to AIDS and immunosuppression in HIV-positive individuals before and after the introduction of the highly active antiretroviral therapy (HAART)].

We evaluated the changes in the progression to death and AIDS and in the mean level of CD4 lymphocytes by calendar period in HIV-positive individuals before and after the introduction of HAART. Through data collected in a prospective cohort study (Italian Seroconversion Study) of 1899 HIV-infected persons with well estimated date of seroconversion, considered as time-zero of analysis, we calculated Kaplan-Meier curves and Cox models, allowing for staggered entries, to estimate the cumulative probability of survival and hazard-ratios (HR) for death and for AIDS by calendar period (1980-1996: pre-HAART era, 1997-1998: first HAART era, and 1999-2001: second HAART era), age at seroconversion, gender, and exposure category. During 17251 person-years, 660 HIV-positive patients developed AIDS and 510 died. Before 1997, the cumulative probability of survival, at twelve years from seroconversion, was 51.0%. In the period 1997-1998 the probability was 77.3% and in the period 1999-2001 it further increased at 91.2%. In the period 1980-1996 only older age at seroconversion was associated with more rapid progression to death. In the period 1987-2001 individuals infected through injecting drug use had a reduced increase of survival compared to those infected through sexual contact. Similar results were obtained for progression to AIDS. Finally we estimated an improved level of immunesuppression in the period 1987-2001. In fact, while in the period 1980-1996 we estimated a decrease of the CD4 lymphocites of -54.8 cells/mm3 (95% CI: -52.0; -57.6) per year; after 1996, we estimated an increase of CD4 of +39.6 (95% CI +34.1; +45.1)per year. This study provides strong evidence that the efficacy of the HAART estimated in the controlled clinical trials has resulted in a real reduction at the population level of morbidity and mortality.