Antiretroviral therapy in HIV-infected individuals in clinical practice: Are the criteria for initiating and choosing the type of drug regimen based only on immunologic and virologic values?

Objectives: To determine factors associated with beginning antiretroviral t herapy and with the number of drugs used. Methods: Longitudinal study of 31 69 HIV-infected individuals naive from anti-retroviral drugs at enrolment i n 65 infectious disease clinics in Italy. Initiation of antiretroviral ther apy and number of drugs used (i.e., <3 vs. greater than or equal to 3 drugs ) were the main outcome measures. Adjusted odds ratios were calculated by l ogistic models to establish cofactors of these two measures. Results: From January 1997 to December 1998, 1288 (40.6%) individuals started therapy, 58 .0% of whom were given a triple combination regimen. This regimen became mo re frequent over time. By multivariate analysis, high levels of HIV-RNA and low CD4 counts were the most important independent predictors of starting any type of therapy. A significant association was also found with HIV expo sure category, reason for being antiretroviral-naive, presence/absence of l iver disease, presence/absence of a new AIDS-defining disease, and clinical centre. High levels of HIV-RNA and low CD4 counts were also the most impor tant predictors of starting with greater than or equal to 3 drugs, compared to < 3 drugs, and men had an independent higher probability of starting wi th greater than or equal to 3 drugs, compared to women. The probability of starting with greater than or equal to 3 drugs significantly increased with calendar time. Conclusions: CD4 and HIV-RNA were the main cofactors of ini tiating both any type of therapy and therapy with greater than or equal to 3 drugs. The large variability among clinical centres suggests that clinici ans are uncertain as to the exact timing of beginning therapy and the speci fic regimen, especially among women.